50S RIBOSOMAL INHIBITORS: Macrolides, Lincosamides, Pleuromutilins, Phenicols

Role of Disturbance: Periodic disturbances such as fire and mowing can reset ecological succession, but timing is crucial to avoid harming vulnerable life stages. Grassland Ecosystems & Butterfly Conservation Key Drivers of Grassland Decline: Land conversion for intensive row-crop agriculture, urban development, fire suppression, overgrazing, and invasive plant encroachment. Timing is critical: unmanaged disturbances during larval or pupal stages can cause high direct mortality. Butterfly Conservation Concepts: (Amphibian Chytrid Fungus): Waterborne zoospores fungus causing chytridiomycosis in amphibians, disrupting cutaneous electrolyte transport and causing cardiac arrest. Umbrella Species: Species whose broad habitat requirement and spatial area encompass the requirements of many co-occurring species; protecting them indirectly protects the broader community. 3 Main Drivers of Butterfly Declines in the U.S.: Habitat loss and fragmentation, pesticide exposure (neonicotinoids/insecticides), and climate change/phenological mismatch with host plants. Chapter 8: Extinction IUCN Red List & Extinction Metrics IUCN Red List: A standardized framework for assessing species extinction risk based on criteria like population reduction and geographic range. Categories of Extinction: Ranges from Extinct (EX) to Least Concern (LC), providing a comprehensive overview of species status. Extinct (EX) Extinct in the Wild (EW) Critically Endangered (CR) Endangered (EN) Vulnerable (VU) Near Threatened (NT) Least Concern (LC) Data Deficient (DD) Contemporary vs. Background Rates: Current extinction rates are estimated to be 100 to 1000 times higher than historical background rates, indicating a biodiversity crisis. Background Rate: ~0.1 to 1 E/MSY (extinctions per million species-years) based on fossil record averages. Contemporary Rate: Estimated at 100 to 1000x higher than background rates over the last 500 years. Sixth Mass Extinction: Current species loss is unprecedented and primarily driven by human activities, contrasting with past extinction events caused by natural disasters. Extinction Terminology: Globally Extinct: No living individuals exist anywhere on Earth. Extinct in the Wild: Survives only in captivity, cultivation, or managed ex-situ populations. Ecologically / Functionally Extinct: Persists in such low numbers that its interactions no longer significantly influence ecosystem structure or function. Extirpation (Local Extinction): Species is eliminated from a specific geographic region but survives elsewhere. Defaunation: Global downscaling of animal numbers and species diversity within local ecosystems. Population Decay: Progressive loss of localized populations across a species' historical range prior to species level extinction. Mass Mortality Event: Rapid, catastrophic die-off of a large percentage of individuals within a population over a brief timeframe. Extinction Debt: Future expected extinctions resulting from past habitat destruction or degradation that have not yet fully played out demographically. Allee Effects: Positive density dependence where individual fitness or per-capita population growth rate declines at low population densities (e.g., failure to find mates, breakdown of group defense). Ranked Proximate Drivers (Most to Least Threatening Global Impact) Demographic & Life History Risk Factors Ecological & Spatial Risk Factors 1. Habitat Loss & Degradation Low intrinsic rate of population growth (r) High endemicity / narrow geographic range 2. Overexploitation High variability in demographic rates Highly isolated populations 3. Invasive Alien Species Large body size / high trophic position Specialized dietary or microhabitat requirements 4. Climate Change Long generation time / late maturation age Reliance on predictable disturbance regimes Chapter 9a: Habitat Loss Land-Use Transitions & Driver Hierarchy Sequence of Land-Use Transitions: The progression from wildlands to urbanization illustrates the increasing human impact on ecosystems. Main Drivers of Habitat Loss: Agricultural expansion (cropland and livestock pasture) Industrial forestry / timber harvest Urbanization and infrastructure development Aquaculture development (e.g., mangrove clearance for shrimp farming) Vulnerable Ecosystems: Most Historical Loss: Tropical dry forests, temperate grasslands, Mediterranean forests, temperate broadleaf forests. Projected Future Losses: Tropical rainforests, tropical savanna ecosystems, peatlands. Forest Change Patterns: Temperate Forests: Globally stabilizing or re-expanding (forest transition hypothesis), but often replaced by low diversity monoculture tree plantations. Tropical Forests: Experiencing rapid deforesting driven by commodity expansion (palm oil, cattle, soybeans, timber extraction). Boreal Forests: Impacted by large-scale logging, industrial extraction (oil/gas), and accelerating climate-driven fires and insect outbreaks. Pacific Northwest (PNW) Forest Ownership: Federal / State Public Lands: Managed under policies prioritizing ecosystem restoration, old-growth protection, and biodiversity conservation (e.g., Northwest Forest Plan). Private Industrial Lands: Managed primarily for short-rotation timber production, leading to younger stand structures and dense road networks. Chapter 9b: Habitat Degradation and Fragmentation Degradation Mechanisms Primary Forms of Pollution: Nutrient Pollution (Nitrogen & Phosphorus): Agricultural runoff and wastewater leading to eutrophication, rapid algal blooms, and hypoxic dead zones ( <2 mg O2/L). Toxic Chemical Contaminants: Persistent Organic Pollutants (POPs) and heavy metals (e.g., mercury) undergo biomagnification, increasing in concentration up trophic levels. Plastic & Debris Pollution: Mechanical ingestion, entanglement, and chemical leaching in marine and freshwater systems. Desertification: Degradation of dryland ecosystems driven by overgrazing, deforestation, and unsustainable farming combined with drought. Regime Shifts & Tipping Points: Loss of vegetative cover destabilizes topsoil, reduces moisture retention, and creates a self-reinforcing feedback loop that shifts fertile drylands to desert. Prevention Techniques: Terracing, rotational grazing, agroforestry, windbreaks, and soil moisture preservation. Fragmentation & Landscape Mosaics A continuous forest changes into a fragmented forest with gaps, which then divides into separate smaller areas. This leads to edge effects, which are changes that occur at the boundary between the forest and non-forest areas. As a result, there can be shifts in the local climate (microclimate) and some species may become isolated from each other. Fragmentation Effects: Subdivides continuous habitat into smaller patches, reduces core area, and increases edge proportion. Effects on Population Growth & Size: Reduces total core area, creates small subdivided populations, elevates mortality along fragment borders, and limits gene flow. Edge Effects: Abiotic (temperature swings, wind shear, lower moisture) and biotic alterations (higher predation rate, invasive weed establishment) occurring along fragment borders. Metapopulation Concept: A network of spatially isolated local populations ("patches") linked by occasional dispersal. Levins Model: dp/dt= cp(1-p)-ep where P is patch occupancy, C is colonization rate, and E is extinction rate. Source-Sink Dynamics & Ecological Traps: Source Populations: High-quality patches where reproduction exceeds mortality ( r>0), producing emigrants. Sink Populations: Low-quality patches where mortality exceeds reproduction (r<0 ), sustained only by immigration (Demographic Rescue Effect). Ecological Trap: Degraded habitat that provides false environmental cues, attracting organisms to select poor-quality habitat where fitness is reduced Chapter 10: Overexploitation Population Models & Harvesting Theory Logistic Growth Model: dN/dt=rN(1-N/K) Maximum Sustainable Yield (MSY):The peak harvest rate achievable without long-term depletion, mathematically occurring at N= K/2 where population growth rate is maximized (MSY=rK/4 ). Fixed-Quota vs. Fixed-Effort Harvesting: Fixed-Quota (Q ): Removing a constant number of individuals. Highly risky; if stochastic events depress population below N^MSY , quota exceeds growth, driving rapid collapse. Fixed-Effort (E ): Regulating harvesting effort ( EN). Yield scales dynamically with population size, providing stability against collapse. Exploitation Types: Types: Commercial (profit-driven, open-access risks), subsistence (local survival), and recreational (leisure, can fund conservation via game ranches). Global Fisheries Trends: Wild marine capture landings plateaued in the 1990s while aquaculture production expanded rapidly; overfished stock percentages are rising globally. Bycatch & Trophic Downgrading: Unintentional capture of non-target species (sharks, rays, seabirds) and removal of large apex predators, altering marine food webs. CITES (Convention on International Trade in Endangered Species): Regulates international wildlife trade across Appendix I (prohibited/threatened with extinction, e.g., rhinos), Appendix II (strictly controlled, e.g., orchids), and Appendix III (national protection assistance). Chapter 11: Invasive Species Terminology & The Invasion Process Native vs. Non-native Species: Native species exist within their historical range, while non-native species are introduced outside their natural distribution due to human activities. Invasive Alien Species (IAS): Non-native species that establish and spread, causing ecological or economic harm, often outcompeting native species. Invasion Phases: Introduction ---> Establishment (surviving environmental and biotic filters via propagule pressure) ---> spread ( Lag phase ---> Expansion Phase ----> saturation phase) Lag Phase & Expansion Phase: Initial low growth during the lag phase followed by exponential growth in the expansion phase as species adapt to local conditions. Propagule Pressure: Refers to the quantity and quality of introduced individuals, a key predictor of establishment success for invasive species. Establishment Hypotheses: Empty Niche, Novel Weapons (allelopathy), Enemy Release, and Novel Environments. Impacts & Management: Biotic homogenization (B -diversity decline), structural disruption (e.g., Brown Tree Snake in Guam, Zebra Mussels), and management prioritizing early prevention and rapid eradication. Chapter 12a: Climate Change Physical Basis & Projections IPCC Framework: The Intergovernmental Panel on Climate Change synthesizes climate data using Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs) to project future climate scenarios. Abiotic Trends: Key trends include rising global temperatures, altered precipitation patterns, ocean acidification, thermal expansion, and melting ice sheets, all contributing to sea-level rise. Aerosol Cooling: Industrial aerosol emissions scatter solar radiation, temporarily masking the warming effects of greenhouse gases, complicating climate change mitigation efforts. Climate Feedback Loops: Positive feedback loops, such as melting ice reducing albedo, exacerbate warming, while negative feedbacks can stabilize certain systems. Mitigation Strategies: Emphasizes the importance of reducing greenhouse gas emissions through renewable energy, conservation, and sustainable practices to combat climate change. Global Climate Agreements: Discusses international efforts like the Paris Agreement aimed at limiting global temperature rise and promoting sustainable development. Drivers & Projections: Rising greenhouse gases, aerosol masking, ocean acidification, sea-level rise, and regional PNW shifts (warmer/wetter winters, hotter/drier summers, reduced snowpack). Ecological Impacts: Poleward/elevational geographic range shifts and phenological mismatches decoupling trophic synchrony. Species Distribution Models (SDMs): Algorithms correlating species presence with environmental layers to project future potential ranges. Climate Vulnerability & Conservation Strategies Climate Vulnerability = f(Exposure, Sensitivity, Adaptive Capacity) Climate Refugia: Geographically buffered microenvironments ("slow lanes") providing short-term climate stability. Migration Pathways: Corridors (e.g., Yellowstone to Yukon) linking protected areas to facilitate natural range tracking. Assisted Colonization (Managed Relocation): Deliberately moving species (e.g., Western swamp turtle) to newly suitable habitats when natural dispersal cannot outpace climate velocity. Building Evolutionary Resilience: Maximizing population sizes, preserving genetic diversity, and conducting gene translocations. Agricultural Expansion Agricultural practices, including cropland and livestock pasture, are primary drivers of habitat loss, leading to significant ecosystem degradation. The conversion of forests and grasslands into agricultural land reduces biodiversity and disrupts local ecosystems. Case Study: The Amazon rainforest has seen extensive deforestation for soybean and cattle ranching, impacting global carbon cycles. Industrial Forestry and Urbanization Industrial forestry practices often prioritize monoculture plantations, which lack biodiversity and resilience. Urbanization leads to habitat fragmentation, reducing the core area of habitats and increasing edge effects. Example: Urban sprawl in the Pacific Northwest has led to the loss of temperate forests, impacting local wildlife. Aquaculture Aquaculture expansion can lead to habitat destruction, particularly in coastal areas where mangroves are cleared for shrimp farming. The environmental impact includes water pollution and disruption of local fisheries. Example: The decline of mangrove forests in Southeast Asia due to shrimp farming has led to increased coastal erosion and loss of biodiversity. Vulnerable Ecosystems and Forest Change Patterns Vulnerable Ecosystems Tropical dry forests, temperate grasslands, Mediterranean forests, and mangroves are among the most affected ecosystems historically. Tropical rainforests and savannas are projected to face significant future losses due to climate change and human activities. Historical Context: The Mediterranean region has seen a dramatic decline in forest cover due to agriculture and urbanization. Forest Change Patterns Temperate forests are stabilizing or re-expanding regionally but are often replaced by low-diversity monoculture plantations. Tropical forests are experiencing rapid deforestation driven by commodity expansion, particularly palm oil and cattle ranching. Boreal forests are impacted by logging, industrial extraction, and climate-driven fires, leading to significant ecological changes. Habitat Degradation and Fragmentation Degradation Mechanisms Pollution and biomagnification of persistent organic pollutants and heavy metals pose severe threats to top predators in ecosystems. Nutrient pollution leads to eutrophication, causing algal blooms and hypoxic conditions in coastal areas, creating 'dead zones'. Example: The Gulf of Mexico experiences seasonal dead zones due to nutrient runoff from agriculture, impacting marine life. Fragmentation Effects Habitat fragmentation subdivides continuous habitats into smaller patches, reducing core area and increasing edge habitat. Edge effects alter microclimates, increasing susceptibility to drought, fire, and invasive species. Global Fragmentation Experiments (e.g., BDFFP in Brazil) show that fragmentation negatively impacts ecosystem functions. Overexploitation and Sustainable Harvest Sustainable Harvest Theory The Logistic Growth Model describes population dynamics and sustainable harvesting levels, emphasizing the importance of carrying capacity (K). Maximum Sustainable Yield (MSY) is the peak harvest rate achievable without long-term depletion, mathematically occurring at half the carrying capacity (N = K/2). Fixed-Quota vs. Fixed-Effort Harvesting: Fixed-quota is risky as it can lead to population collapse, while fixed-effort adjusts yield based on population size. Exploitation Contexts Types of exploitation include commercial, subsistence, and recreational, each with different ecological impacts and regulatory needs. Global fisheries trends indicate a plateau in wild marine capture while aquaculture production expands, raising concerns about overfishing. Bycatch and trophic downgrading disrupt marine food webs, leading to ecological imbalances. Invasive Species and Climate Change Invasion Process and Management Definitions: Native vs. non-native vs. invasive alien species (IAS) that cause ecological harm. Invasion stages include introduction, establishment, and spread, with various hypotheses explaining establishment success. Management strategies prioritize early prevention and rapid eradication to mitigate impacts of invasive species. Climate Change Impacts Rising greenhouse gases and climate change lead to shifts in species distributions and phenological mismatches, disrupting ecological interactions. Climate vulnerability is assessed based on exposure, sensitivity, and adaptive capacity, guiding conservation strategies. Assisted colonization may be necessary for species unable to migrate fast enough due to climate velocity.

A Level Chemistry - Synthetic Routes: Phenols

Bio test pheno/genotype

Phenom

Phenology (Exam 2)

Organic Chemistry: Haloalkanes, Haloarenes, Alcohols, Phenols, Ethers, and Carbonyl Compounds

Alcohols and Phenols Theory and Reactions

4.3 Alcohols and phenols

Current Political Phenom Midterm

29. An introduction to A Level organic chemistry Formulas, Fn groups, Naming Functional groups and formulae Functional group: atom/group of atoms in an organic molecule that determines its characteristic chemical and physical properties Arenes: aromatic compounds that contain a benzene ring chemical properties Compound can undergo Electrophilic attack: is e- rich due to π system of delocalised e- Resistant to addition reactions: delocalised e- ring system makes benzene stable physical properties b.p 80 C: Benzene has id-id forces of attraction between the molecules Insoluble in water: non-polar hydrocarbons in arene (not energetically favourable for benzene to break many H bonds between water molecules to be soluble) Halogenoarenes: aromatic compounds containing halogen bonded to benzene ring chemical properties Prone to Electrophilic attack can take part in substitution reactions physical properties Chloro, broom, iodo benzene liquid at r.t with oily texture b.p. Increases down group: larger halogen = more e- = stronger id-id forces = more energy to separate insoluble in water: non-polar hydrocarbon ring Phenols: aromatic compounds containing a hydroxide bonded to benzene ring chemical properties acidic: O in -OH donates a lone pair into ring (more acidic than alcohols) = increased e- density in ring = more reactive = easier for H to be donated react with reactive metals (e.g. Na) to form phenoloxide ions and H gas physical properties White, crystallline solid disinfectant-like smell soluble in water: can form H bonds with water due to -OH group Acyl chlorides: carboxylic acid derivatives containing a chlorine atom, and an acyl group attached to C=O chemical properties colourless extremely reactive and readily takes part in substitution (Cl substituted ) fuming liquids with strong smell: react with water vapor in air Physical properties react violently with water (cannot determine its solubility with water ) Amines: compounds with -NH2 (primary), -NH (2 °) , or -N (3 ° ) amine group chemical properties basic compounds: due to lone pair of e- on nitrogen physical properties lone pair on N can form H bonds soluble in water: form H bond with water solubility ↓ as nonpolar hydrocarbon chain gets longer / molecule gets bigger fishy smell Amides: compounds containing amine group (-NH2) carbonyl group (C=O) amide group -CONH2 chemical properties less basic than amides: lone pair of e- on N is delocalised physical properties soluble in water: form H bonds with water solubility ↓ as nonpolar hydrocarbon chain gets longer / molecule gets bigger Amino Acids: building blocks of proteins, consisting amine group (-NH2) and carboxylic group (-COOH) chemical properties react with bases to form salts react with alcohols to form esters react with amines to form amides physical properties most are soluble in water but insoluble in organic solvents most have chiral centres, exhibit optical isomers Formulae of Organic Compounds Nomenclature of Compounds Naming organic compounds Identify longest C chain containing the functional group Identify fn group on the chain to determine the suffix or prefix on the compound Count along the carbon chain such that the functional group has the lowest number Add any side chains or lower priority functional groups as prefixes to the beginning of the name in alphabetic order Use the prefixes di-, tri- and tetra- if there are two or more identical functional groups or side chains Characteristic organic reactions Electrophilic substitution Electrophile: e- loving species they are e- deficient and acts as e- pair acceptor Substitution reactions: reactions replacing 1 atom / group by another Electrophilic substitution: group / atom replaced by an electrophile e.g. bromine electrophile attacks e- - rich benzene ring Addition-elimination (nucleophilic) nucleophilic addition of small molecule followed by elimination of small molecule includes hydrolysis reaction of alcohols to form esters reaction with ammonia and 1° amines to form amides e.g. Hydrolysis of acyl chlorides Hydrolysis - acyl chloride to carboxylic acid water molecule adds across C=O bond HCL eliminated Ester formation - acyl chlorides + alcohol Alcohol adds across the C=O bond HCl molecule is eliminated Amide formation - acyl chloride + 1° amines + conc ammonia amine or ammonia adds across C=O bond (lone pair on N attacks carbonyl C atom in acyl chloride) HCl eliminated Shapes of aromatic organic molecules Aromatic molecules consist of one or more rings with conjugated π systems Conjugated π systems arise from alternating double and single bonds in which the electrons are delocalised Shape of benzene and aromatic compounds - why are they more stable? Benzene and other aromatic compounds are planar and regular because each carbon atom is sp² hybridised. Each C forms three σ bonds in a trigonal planar arrangement with bond angles of 120°. The remaining unhybridised p orbital on each carbon overlaps sideways with neighbouring p orbitals to form a continuous, delocalised π system above and below the ring. Because the π electrons are delocalised over the whole ring, all the C–C bonds are identical and have intermediate character between a single and double bond. This is why benzene is unusually stable. Why are benzene more stable? delocalised π electrons above and below the ring Optical isomerism, Chirality and drug production Stereoisomers: same structural formula, diff arrangement in space (geometrical, optical) Optical 4 diff groups of / atoms central chiral carbon chiral molecules exist as 2 optical isomers / enantiomers non-superimposable mirror images same physical / chemical properties rotate in opposite directions in plane polarised light (1 clockwise 1 anticlockwise ) Similarities of enantiomers differences in enantiomers same physical and chemical properties differ from ability to rotate plane polarised light and biological activity nonsuperimposable mirror images Biological activity of enzymes enzymes are chiral proteins, bond to specific active site for biological response mirror image of enantiomer will not bind to same active site as it is not the same shape, no biological response Optical activity and Racemic mixtures reaction mixture is optically active if there is an uneven mixture of each enantiomer (e.g. 20% rotates clockwise, 80% rotates anticlockwise, net effect is plane of polarised light rotates anticlockwise) racemic mixture: equal amounts of enantiomers present in soln optically inactive as enantiomers cancel out each others effect, plane polarised light not changed the rotation of plane polarised light can be used to determine the identity of an optical isomer e.g. pass plane polarised light through a sample containing one of the two optical isomers of a single substance Depending on which isomer sample contains, the plane polarised light will be rotated clockwise / anti-clockwise clockwise rotation: R enantiomer anticlockwise rotation: S enantiomer No effect will be observed when the sample is a racemic mixture Chirality and Drug production most drugs to treat disease have 1+ chiral centres and can ∴exist as enantiomers diff in biological activity in enantiomers means difference in effectiveness as medicine drugs should be prepared so that only 1 optical isomer produced, to ↑ effectiveness Potential different biological activity of enantiomers e.g. drug naproxen treats pain from arthritis 1 enantiomer eases pain 1 enantiomer causes liver damage separate racemic mixture into 2 pure enantiomers due to difference in biological activities reduce side effects ↓ dosage by half, reduces production cost chiral catalysts to produce 1 pure optical isomer only small amount chiral catalysis needed + reused e.g. enzyme 30. Hydrocarbons - Arenes Reactions of arenes substitution halogenation nitration Friedel-Craft's alkylation Friedel-Craft's acylation other reaction Complete Oxidation Hydrogenation Electrophilic substitution electrophile: e- pair acceptor, attracted to delocalised e- substitution: 1+ H replaced by a fn group generating electrophile+ using catalyst Electrophilic attack on benzene ring (electrophile accepts 2 π e- , +ve charge remains) regenerating aromaticity by heterolytically cleavage of C-H bond (bonding pair foes into benzene π system) Addition reactions of arenes arenes undergo substitution due to delocalisation of e-, aromaticity restored by heterolytic cleavage of C-H bond in addition, aromaticity / stability not restored (e.g. hydrogenation), Hydrogenation of benzene is less exothermic than expected for three isolated C=C bonds, because the aromatic stabilisation of benzene is lost Halogenation (in the aromatic ring) reactants: Cl2 / Br2 (Cl+ / Br+ electrophile) , arene conditions: rt and pressure catalyst: anhydrous AlCl3 / AlBr3 (catalyst needed due to stability of benzene structure) formation: AlCl3 + Cl2 ⇒ AlCl4- + Cl+ reformation: H+ + AlCl4- ⇒ AlCl4 + HCl product: halogenoarenes / aryl halide In halogenation of Alkylarenes, e- donating alkyl group activates positions 2, 4 (as well as OH-, NH2). forms 2 products multiple substitutions when excess halogen used Halogenation (of alkylarenes) in side chain free radical substitution reaction reactants: halogen, boiling alkyl arene conditions: UV light if excess halogen: all H on alkyl side chain will be substitution by X atoms Nitration reactants: conc HNO3 (NO2+ electrophile), arene conditions: 20-60 ° C (higher = more NO2+ substituted) catalyst: conc H2SO4 formation: HNO3 + H2SO4 ⇒ NO2+ + 2HSO4- + H3O+ reformation: H+ + HSO4- ⇒ H2SO4 In nitration of Alkylarenes, e- donating alkyl group activates positions 2, 4 Friedel-Crafts alkylation substitution of alkyl chain reactant: chloroalkane (CH3CH2+ electrophile), arene condition: heat under reflux catalyst: anhydrous AlCl3 formation: AlCl3 + CH3CH2Cl ⇒ CH3CH2+ + AlCl4- reformation: AlCl4- + H+ ⇒ AlCl3 + HCl Friedel-Crafts acylation substitution of an acyl group (group containing carbonyl, C=O ) reactant: acyl chloride (CH3CH2CO+ electrophile) conditions: heat under reflux catalyst: anhydrous AlCl3 formation: AlCl3 + CH3CH2COCl ⇒ CH3CH2C=O+ + AlCl4- reformation: AlCl4- + H+ ⇒ AlCl3 + HCl Complete oxidation of side chains alkyl side-chains in alkyl arenes are oxidised to carboxylic acids when refluxed with alkaline KMnO4 and then acidified with dilute H2SO4 reactants: hot alkaline KMnO4, dilute H2SO4, alkyl arenes conditions: heat under reflux Hydrogenation addition reaction to form cyclohexane reactants: H2 gas conditions: heat (200 ° C at 30 atm ) catalyst: Pt/Ni Directing effects of substituents on arenes substituents: already on arene that direct substitution reactions to diff. ring positions E- withdrawing groups / substituents e- donating groups / substituents remove e- density from π system in benzene ring deactivating groups (slow attack by e+) directs e+ to positions 3, 5 e.g. COOH, X, NO2 donate e- density into π system of benzene ring activating groups (allow e+ to react faster) directs e+ to positions 2, 4, 6 e.g R, NH2, OH 31. Halogen compounds Halogenoarenes: arenes bonded to X atoms Producing halogenoarenes substitution reactions of arenes with chlorine or bromine in presence of anhydrous AlCl3 catalyst reactants: Cl2 / Br2 (Cl+ / Br+ electrophile) , arene conditions: rt and pressure catalyst: anhydrous AlCl3 / AlBr3 (catalyst needed due to stability of benzene structure) formation: AlCl3 + Cl2 ⇒ AlCl4- + Cl+ reformation: H+ + AlCl4- ⇒ AlCl4 + HCl product: halogenoarenes / aryl halide Substitution of benzene Substitution of methylbenzene substitution of 6 position only occurs in excess chlorine Reactivity of halogenoarenes Why are aryl halides less reactive than haloalkanes? C-H bond in aryl halides is stronger due to the partial overlap of lone pairs on halogen atom with the π system in the benzene ring C-H bond ∴ has a partial double bond character 32. Hydroxy compounds Reactions of alcohols Formation of esters reaction: addition-elimination (esterification) reactants: alcohols/phenols, acyl chlorides nucleophile: OH- (attacks e- deficient carbonyl (COCl) C ) COCl bond breaks, Cl is substituted, HCl fumes formed Why are esters formed from acyl chlorides rather than from C. acids? more effective to form esters from acyl chlorides acyl chlorides are more reactive (produce esters faster) acyl chloride reactions go to completion (more ester formed) Esterification using phenols additional reactants: base (e.g. NaOH) base: deprotonate phenol to form phenoxide ion phenoxide better nucleophile than phenol, attack on carbonyl C occurs more readily Phenol phenol: benzene ring with -OH group attached Production of Phenol From reaction of phenylamine with nitrous acid (HNO3) reactants: NaNO2, dilute acid (to form HNO2), phenylamine conditions: ice (under 10 ° C) step 1 and 2, heat step 3 forming nitrous acid NaNO2 + HCl ⇒ (ice) HNO2 + NaCl forming unstable diazonium salt forming phenol via thermal decomposition (due to instability) reactions of phenol Many reactions due to e- rich benzene ring and polar -OH group with bases with reactive metals with diazonium salts nitration bromination Acid-base reactions Acid-base reaction of phenols with base -OH: slightly acidic (weak acids), act as acid in acid-base reaction dissolve in alkaline soln forming phenoxide salt and water Acid-base reaction of molten phenols with reactive metals forms soluble phenoxide salt and H2 gas Reaction with diazonium ions diazonium ions very reactive due to -N2+ group acid-base reaction conditions: ice for cold diazonium ion added to phenoxide ion Reactions of the aromatic ring phenols react more readily with e+ than benzene due to one lone pair of e- on O in -OH overlaps with π bonding system, ↑ e- density of phenol’s benzene ring and making it more susceptible to electrophilic attack -OH activates ring, directs e+ to 2, 4, 6 positions Nitration of phenols electrophilic substitution reaction reactant: dilute HNO3, phenol when conc HNO3 used, product is 2, 4, 6- trinitrophenol conditions: rt milder conditions as phenol is more reactive Bromination of phenols electrophilic substitution reaction reactants: bromine water, phenol conditions: rt phenol decocolourises orange bromine soln to form 2, 4, 6 - tribromophenol (white ppt) as phenol is more reactive, no need for anhydrous AlBr3 catalyst, can react with bromine water Reactions of other phenolic compounds (contain phenol functional group, e,g, 1-naphthol) -OH group is also e- donating, activates benzene ring to electrophilic substitution reactions, e+ directed to 2, 4 positions (on phenol) C in position 6 shared by both rings, no H atom = no substitution can react in similar way as phenol Acidity of phenols Phenols are weak acids phenols react more readily with e+ than benzene due to one lone pair of e- on O in -OH overlaps with π bonding system, ↑ e- density of phenol’s benzene ring and making it more susceptible to electrophilic attack Phenol’s conjugate base is the phenoxide ion. -ve charge is delocalised over the entire ion as a lone pair on O overlaps with the ring’s delocalised π system, which reduces charge density on oxygen H⁺ ions are ∴ less strongly attracted to phenoxide ion, so phenol is less likely to reform Therefore, phenol is more likely to lose H⁺ and act as an acid Stability of conjugate base phenoxide more stable as -ve charge spread out, so phenol more likely undergo ionisation eqm shifts right, more phenol donate H+ (act as acid) Relative acidities of water, phenol, ethanol smaller pKa = stronger acid order of acidity explained by conjugate bases Delocalisation of charge density phenoxide (conjugate base of phenol): charge density of O is spread out over ion, O less available for bond formation with H+ ethoxide (conjugate base of ethanol): ethyl group is e- donating, donates e- density to O atom, O more available for bond formation with H+ hydroxide (conjugate base of water): charge density of O cannot become delocalised over a ring, OH- more readily accepts H+ than phenoxide no e- donating alkyl groups to O, less -ve O, O less readily accepts H+ compared to ethoxide Overall conjugate base more readily accepts H+ = stronger conjugate base = weaker acid strong acid eqm shifts right favouring dissociated ions and H+ 33. Carboxylic acids and derivatives Benzoic acid: C6H5COOH can be used to synthesize esters Carboxylic acids Production of benzoic acid formation of benzoic acid from Oxidation of alkylbenzenes alkylbenzene heated under reflux with hot alkaline KMnO4, then acidified with dilute acid to protonate carboxylate salt and form benzoic acid reactants: hot alkaline KMnO4 (oxidising agent), dilute acid (e.g. HCl), alkylbenzene purple Mn2+ turns colourless as reduced to Mn4+ brown ppt MnO2 formed conditions: heat under reflux Reactions of Carboxylic acids Reactions of C, acids to form acyl chlorides reactants PCl5 (s) PCl3 (l) + heat SOCl2 (l) Forming carboxylic acids from oxidation of 1 ° alcohols alcohol ⇒ aldehyde ⇒ c. acid Further oxidation of c. acids such as methanoic and ethanedioic acid methanoic acid (strong reducing agent) gets further oxidised to CO2 by warming with mild oxidising agents like Fehling’s or Tollen’s reagent Fehlings: Cu2+ reduced to Cu+, form red ppt Cu2O Tollens: Ag+ reduced to Ag using stronger oxidising agents like acidified KMnO4 or acidified K2Cr2O7 KMnO4: purple soln turns colourless as Mn7+ reduced to Mn2+ K2Cr2O7: orange soln turns green as the Cr6+ reduced to Cr3+ ions Ethanedioic acid gets further oxidised to CO2 Conditions: Strong oxidised agent - warm acidified KMnO4 needed Relative acidities of C. acids, Phenols, and alcohols C acids can lose H+ in aq soln to form carboxylate salts and water Acidities of C. acids longer C chain = weaker acid inductive effect ↑ -ve charge on COO- group More substituted Cl atoms = stronger acid Cl atoms withdraw e- density from the –COOH group, weakening the O–H bond and stabilise carboxylate ion (reducing the -ve charge density on it) The more stable the carboxylate ion, the less likely it is to attract H⁺ and reform the O–H bond Acidities of c. acids, phenols, alcohols acidities explained by strength of O-H bond and stability of conjugate bases of acids Strength of O-H bond carboxylic acids e- in O-H bond drawn towards C-O bond, e- in C-O bond drawn to C=O bond O-H bond weakened due to C=O withdrawing e- density from it for itself easier to act as acid and lose H+ from OH alcohols lack e- withdrawing C=O group, O-H bond not weakened harder to act as acid and lose H+ Stability of conjugate bases carboxylate ion (c base of carboxylic acid) charge density on O spread over ion because charge is delocalised on an electronegative carbonyl O atom O less available for bond formation with H+ to reform -COOH eqm shifts right, C base more stable than carboxylic acid alkoxide ion (c base of alcohol) alkyl is e- donating group, donates e- density to O atom O more available for bond formation with H+ ion to reform OH lack ability to delocalised charge density on ion, c bases less stable than alcohols, weaker acids than c. acid and phenols eqm lies left phenoxide ion (c base of phenol) charge density of O spread out over ion due to delocalisation of e- (stabilises ion) O less available for bond formation with H+ Phenoxide more stable than phenol Phenoxide less stable than carboxylate since delocalisation of charge density is on C atoms, not electrogenative O atoms eqm lies more right than alcohols, more left than c. acids ethanol is weakest e- donating methyl group strengthens O-H bond methyl donates -ve charge to -COO-, more likely to accept H+ Esters - Production Esters: organic compounds with -COO- functions group nice smelling Naming esters alcohol acyl chloride / carboxylic acid e.g. Producing esters from alcohols and carboxylic acids condensation / esterification reaction Producing esters from alcohols and acyl chlorides more effective: acyl chlorides more reactive(faster), and reactions go to completion (no eqm, max yield) Acyl Chlorides Acyl chlorides: compounds with COCl fn group Production of acyl chlorides Carboxylic acid with solid PCl5 liquid PCl3 + heat liquid SOCl2 Reactions of acyl chlorides addition-elimination: addition of small molecule across C=O, followed by elimination of small molecule acyl chlorides under addition-elimination reactions such as hydrolysis to form carboxylic acid Reaction with alcohols and phenols to form esters Reaction with ammonia and amines to form amides General mechanism for addition-elimination reactions addition of nucleophile across C=O bond elimination of a small molecule such as HCl or H20 lone pair on nucleophile carries out initial attack on carbonyl carbon this is followed by the elimination of an HCl molecule Hydrolysis of acyl chlorides forms carboxylic acid and HCl water (nucleophile) adds across C=O bond HCl eliminated Formation of esters from acyl chlorides esterification reaction reactants: alcohol/phenol, acyl chloride conditions: rt reaction with phenol is slower than alcohol, base such as NaOH used to speed up reaction (deprotonates phenol to form phenoxide, better nucleophile to carry out attack) alcohol /phenol (nucleophile) adds across C=O bond, HCl / NaCl eliminated Formation of amides from acyl chlorides condensation reaction: nucleophile adds to C=O, Cl- eliminated, HCl formed reactants: ammonia or 1°/2 ° amines, acyl chloride nucleophile: Nitrogen (has lone pair of e- ) HCl formed is immediately neutralised by a 2nd molecule of ammonia / amine in excess, forming ammonium salt (e.g. NH4Cl, CH3NH3Cl) Relative ease of hydrolysis of aryl chlorides from most readily broken / easily hydrolysed acyl chloride > alkyl chloride > aryl chloride trend explained by strength of C-Cl bond acyl chlorides - hydrolysed at rt R-COCl C bonded to Cl is also bonded to O both Cl and O are very electronegative, pulling e- away from C, leaving it very δ+ C-Cl bond is weakened nucleophilic attack is more rapid alkyl chloride - hydrolysed by refluxing with strong alkali nucleophile R-C-Cl C bonded to Cl attached to 1 electronegative atom (Cl), pulls e- away from C C is not very δ+ (e- deficient) C-Cl bond is stronger than in acyl chlorides aryl chlorides - hydrolysis will not occur C bonded to Cl is part of delocalised π bonding system of benzene ring one lone pair of e- on Cl overlaps with delocalised system C-Cl bond has some double bond character, becoming stronger 34. Nitrogen compounds Primary and secondary amines 1 ° amines: organic compounds with NH2 fn group attached to an alkyl / aryl group 2 ° amines: organic compounds with group attached to a alkyl /aryl groups Naming -amine: after alkyl prefix (e.g. methyl amine) amino- : if another suffix present or branched/complex amines (e.g. amino methane) Production of Amines 1 ° and 2 ° amines prepared form diff reactions 1 ° amines: reaction of haloalkanes with ammonia reduction of nitriles reduction of amides 2 ° amines: reaction of haloalkanes with 1 ° amine Forming 1 ° amines from haloalkanes with ammonia nucleophilic substitution reaction reactants: excess, hot ethanolic ammonia nucleophile: N in ammonia (replaces X) conditions: heat under pressure Forming 1 ° amine from reduction of nitrile reactants: nitrile vapour, H2 gas conditions: LiAlH4 in dry ether (reducing agent), or Ni catalyst Forming 1 ° / 2 ° amines from reduction of amides reactants: LiAlH4 in dry ether (reducing agent) type of amine depends on nature of amide Forming 2 ° amines from haloalkanes with 1 ° amine nucleophilic substitution reaction reactants: 1 ° amine in ethanol nucleophile: N in 1 ° amine (replaces X) conditions: heat under pressure, sealed tube Reactions of Amines Condensation reaction between Acyl chloride and ammonia or amine produces Amides Cl in acyl chlorides is electronegative, draws e- density from carbonyl C C is e- deficient, attacked by nucleophile like N in ammonia and amines C-Cl bond broken, amide formed reaction with amines ⇒ substituted amide reaction with ammonia ⇒ nonsubstituted amide Why is acyl chloride a more effective reactant than carboxylic acids in formation of amides? c acids less reactive than acyl chloride reaction with c acids dosent fo to completion Basicity of aq soln of Amines and ammonia N in ammonia and amines can accept proton H+, can ∴ act as bases in aq soln (when donating lone pair to form dative bonds) Strength of bases strength of amine depends on availability of lone pair of e- on N to form a dative covalent bond with H+ lone pair more readily available to form dative bond = stronger base positive inductive effect ↑ basicity: alkyl groups donate e- density to N, causing lone pair to become more available delocalisation ↓ basicity: aromatic rings cause lone pair to be delocalised into benzene ring, causing lone pair to be less available Phenylamine and Azo compounds Phenylamine: organic compound with benzene ring and amine fn group Production of phenylamine 3 step synthesis, followed by separation / purification Nitration (forming nitrobenzene) reactants: benzene, conc HNO3 catalyst: conc H2SO4 conditions: 25-60 ° C Reduction (forming phenylamine ion) conditions: hot tin (Sn) and conc HCl under reflux Deprotonation (forming phenylamine) reactants: NaOH, phenylamine ion separation/purification phenylamine separated from reaction mixture by steam distillation Reactions of Phenylamine Both benzene ring and NH2 can take part in chemical reactions bromination of phenylamine formation of diazonium salt Bromination of phenylamine to form 2, 4, 6- tribromophenylamine electrophilic substitution reaction electrophile: N, donate e- density into benzene ring, ↑ e- density in benzene ring activates it, more readily attacked by electrophiles reactants: aqueous bromine, phenylamine conditions: rt Formation of diazonium salt (salt containing N2+ group) reactants: nitrous acid/HNO2, HCl, phenylamine HNO2 formed in test tube with NaNO2 and dilute HCl conditions: below 10 ° C diazonium salt forms phenol upon warming with water Azo compounds Azo compounds: organic compounds with R-N=N=R / azo group often used as dyes Diazonium compounds: contain N2+ group Formation of Azo compounds from coupling reaction of benzene diazonium chloride salt with phenol multi-step process forming nitrous acid reactants: NaNO2, HCl conditions: test tube, under 10 °C / ice NaNO2 + HCl ⇒(ice) HNO2 + NaCl Diazotisation reactants: phenylamine, HNO2, dilute HCl conditions: below 10 ° C / ice (prevent thermal decomposition of diazonium ion to phenol, N and HCl) coupling reaction reactants: phenol, diazonium ion (acts as electrophile, sub into benzene ring of phenol) conditions: alkaline conditions (NaOH deprotonates phenol to phenoxide, more reactive to e+) Why are azo compounds very stable? The delocalised e- in π bonding systems extend across both benzene rings and the –N=N– bridge Other days formed from similar route e.g. formation of yellow dye from coupling reaction between benzene diazonium chloride and C6H5N(CH3)2 Amides Amide: organic compounds with CONR2 amide group non-substituted / 1 ° amide: N bonded to 2H atoms substituted / 2 ° amide: 1 or both H replaced by a hydrocarbon group Production of Amides Formation of Amides from acyl chlorides / c. acid with ammonia / amine condensation reaction: nucleophile adds to C=O, Cl- eliminated, HCl formed nucleophile: Nitrogen (has lone pair of e- ) conditions: rt HCl formed is immediately neutralised by a 2nd molecule of ammonia / amine in excess, forming ammonium salt (e.g. NH4Cl, CH3NH3Cl) Reactions of Amides Amide group can undergo reactions Hydrolysis with aqueous alkali or aqueous acid Reduction with LiAlH4 Hydrolysis of amides to form c. acid and ammonia/ 1 ° amine conditions: reflux with aq acid / alkali products differ depending with amide is substituted nonsubstituted ⇒ c. acid + ammonia substituted ⇒ c. acid + 1 ° amine when refluxed in excess acid⇒ ammonium salt formed base⇒ carboxylate ion formed (deprotonation) Reduction of amides to form amine conditions: LiAlH4 reducing agent nonsubstituted amide ⇒ 1 ° amine + H2O substituted amide ⇒ 2 ° amine + H2O Relative basicity of Amides and Amines lone pair of e- more readily available for dative bonding = stronger base more e- =stronger base amides - weaker base e- withdrawing O in C=O causes lone pair on N to delocalise into C=O group, removed e- density from N lone pair on N less readily available for bonding amine - stronger base e- donating alkyl groups ↑ e- density on N lone pair on N more readily available for bonding Amino Acids Amino acids: organic compounds with 2 fn groups basic amino -NH2 group acidic carboxylic acid -COOH group due to presence of basic and acidic group, they are amphoteric (act as acid and base) R group can be acidic, basic, or neutral Acid-base properties of amino acids + formation of Zwitterion amino acids can undergo most reactions of amines and c. acids, including acid-base reactions (amine + acid, C. acid + base) Amino acids can interact intramolecularly to form zwitterion Zwitterion: ion with both +ve (NH3+) and -ve (COO-) charge formed from amino acids in water due to charges, there are strong intermolecular forces of attraction between amino acids this makes amino acids soluble crystalline solids Zwitterions act as buffer soln acid added: pH ↓ COO- accepts H+ to reform COOH, zwitterion becomes +vely charged base added: pH ↑ NH3+ donates H+ to reform NH2, zwitterion becomes -vely charged Isoelectric point: point at which charge = 0 / zwitterion is neutral a pH level unique to each amino acid due to R group Formation of Peptide bonds NH2 group of one amino acid can react with COOH group of another amino acid to form dipeptide condensation reaction: H2O eliminated peptide bond / link formed dipeptides can undergo condensation reaction again to form tripeptide ( 3 amino acids) polypeptide: many amino acids join to form long chain of molecules proteins are polypeptides Electrophoresis Analytical separation technique, separates ions by placing them in an electric field Sample of amino acids placed between 2 oppositely charged electrodes +ve ions move to -ve electrode -ve ions move to +ve electrode Rate of ion movement depends on size of ions (larger = slower) charge of ions (highly charged = quicker) Electropherogram: bands on gel after electrophoresis each band = particular species Amino acids can be separated according to charge and mass they are colourless, sprayed with ninhydrin (brown/purple stain) to show where they have gone to Changes in charge of amino acid due to pH of solution isoelectric point: no overall charge, no movement of zwitterions pH > isoelectric point: -ve charge, move to +ve electrode pH < isoelectric point: +ve charge, move to -ve electrode -ve charged amino acid: NH3+ donated H+, NH2 and COO- left +ve charged amino acid: COO- accepted H+, NH3+ and COOH left 35. Polymerisation Condensation Polymerisation - Forming polymers Forming polymers such as polyesters, polyamides, proteins Formation of polyesters addition polymerisation: monomers with C=C bonds join to form polymers condensation polymerisation: Small molecule is lost when monomers join together to form polyester polyesters have ester links Monomers for polyesters OH on dicarboxylic acid and H of diol expelled as H2O to form polyester diol (2 -OH) + dicarboxylic acid (2 -COOH) 2 hydroxy carboxylic acids (OH and COOH fn group) Formation of polyamides condensation polymerisation polyamides have peptide links Monomers for polyamides H on diamide and OH on dicarboxylic acid / Cl on dichloride expelled as H2O / HCl as polyamide forms diamide (2 -NH2) + dicarboxylic acid diamide + dichloride (2 -COCl) 2 aminocarboxylic acids (OH and COOH fn group) Making proteins/polypeptides from amino acid monomers (aminocarboxylic acid) amine group (-NH2) and carboxyl group (-COOH) of an amino acid polymerise with another amino acid forms peptide links proteins can be broken into its constituent amino acids through hydrolysis You can deduce the repeat units of a condensation polymer by identifying the linking between monomers chain of C: addition polymer ester link: polyester peptide link: polyamide You can identify monomers from small molecule expelled H2O: c acid H: amine Cl: dioyl chloride Predicting type of polymerisation Identifying type of polymerisation by looking at functional groups Addition polymerisation monomer contains C=C bond double bond opens up to add monomers to either side of starting polymer forms polyalkenes co-polymer: 2+ monomers used to make 1 repeating unit Condensation polymerisation makes polyamides and polyesters summary: Identifying type of polymerisation by considering structure of polymer backbone Addition polymerisation no fn groups on polymer backbone, usually chain of C atoms sidechains might branch off from backbone (e.g. benzene rings, nitrile groups (CN), halogens Condensation polymerisation backbone of polyesters contain ester links (-COO-) backbone of polyamides contain peptide links (-CONH-) Degradability of Polymers Polyalkenes and biodegradability polyalkenes are nonpolar and saturated, making them nonbiodegradable and chemically inert instead, they can be melted and recycled for new uses The energy released from burning can be used to generate electricity Burning plastics in oxygen releases carbon dioxide and water (complete combustion) which can contribute to global warming Photodegradation of polymers some polymers are biodegradable due to their ability to breakdown using light C=O groups along polymer chains absorb UV light this weakens C=O areas of polymers and breaks them down into smaller molecules e.g for polyesters and polyamides Disadvantages of photodegradability weaker polymers UV light not available (e.g. in landfills) Biodegrading polyesters and polyamides via hydrolysis polyesters and polyamides can be broken down by hydrolysis (advantage) hydrolysis: breakdown of molecules using water acid hydrolysis: acid catalyst used alkaline hydrolysis: alkaline catalyst used heating with catalyst breaks polymer Hydrolysis of polyamides acid hydrolysis: breaks polymer into di carboxylic acid and ammonium ions alkali hydrolysis breaks polymer into its sodium salts (e.g. dicarboxylic acid salt and diamines) Hydrolysis of polyesters acid hydrolysis: diol + dicarboxylic acid alkali hydro lists: diol + dicarboxylic acid salt 36. Organic synthesis Elucidating organic molecules - fn groups, properties, reactions Fn groups in AS required as well as: Production of fn groups benzoic acids acyl chlorides amides Producing benzoic acid reactants: methylbenzene oxidation: reflux with hot alkaline KMnO4 to form potassium benzoate protonation with dilute HCl to form benzoic acid Producing acyl chlorides reactants: c. acid substitution reaction: -OH replaced by Cl Producing amides condensation reaction reactants: acyl chloride, NH3 (nonsubstituted amide) / methyl amine (substituted amide) conditions: rt Reactions of functional groups Electrophilic substitution reactions of benzene reaction electrophile halogenation X+ nitration NO2+ alkylation R+ acylation RCO+ Hydrogenation of benzene addition reaction Esterification of phenol more efficient with acyl chloride than carboxylic acid Acid-base reactions of phenol phenol + base ⇒ soluble salt + water Nitration of phenol Bromination of phenol Multi-step synthetic routes Aliphatic reactions Aromatic reactions Analysis 37. Analytical techniques Thin- Layer Chromatography (TLC) Separate small samples 2 phases: stationary and mobile phase Stationary phase thin metal sheet coated in Al2O3, or SiO2 solutes adsorb onto surface and travel thru plate Mobile phase flows over stationary phase polar (water or alcohol) or nonpolar (alkanes), any liquid solvent or gas solvent carries components investigated in coloured components: investigated under UV light using ninhydrin Conducting a TLC analysis prep beaker with small amount of solvent on TLC plate, draw baseline in pencil place spot of reference compound on the left, then a spot of sample on right of baseline and air dry reserve allows identification of compounds in sample put TLC plate inside beaker with solvent - make sure pencil line above solvent, place lid to cover beaker as solvent reaches top, remove plate and draw another pencil line where solvent reached (solvent front) to use to calculate Rf Rf values The extent to which components are separated depends on solubility of each component in the mobile phase and interaction between each component and the stationary phase less polar components travel further up ⇒ larger Rf ⇒ more soluble in mobile phase more polar components do not travel far up ⇒ more attracted to polar stationary phase Gas / Liquid chromatography Analysing bases, volatile liquids, solids in vapour form Stationary phase nonpolar, non-volatile liquid applied to the inner walls of a capillary column mobile phase unreactive carrier gas noble, or inert diatomic e.g. He, N2, Ar Retention time: time taken for sample molecule to travel through the column from time inserted to time detected often recorded on chromatogram each peak = a volatile compound in the analysis sample. each peak has its own rt rt compared with data book values to identify unknown molecules longer rt: nonpolar components, attractiveness to nonpolar liquid in stationary phase shorter rt: polar components, interact with carrier gas Relative concentration of each component = area under each peak Area under peak = ½ base x height peaks roughly take shape of Δ % composition of a particular molecule in a mixture Carbon-13 NMR spectroscopy carbon-13 NMR : analytical tool used to analyse samples and determine the structure of substances Each Carbon environment gives a peak solvent used to dissolve samples for 13C-NMR : CDCl3 (solvent peak around 70 ppm) all 13C-NMR spectra measured relative to TMS / tetramethylsilane ( 0 ppm) predict the number of carbon environments refers to a specific c atom and the combination of atoms, bonds, fn groups attached each unique c environment produces a peak in 13C - NMR if there is a line of symmetry through the molecule, they belong to same environment and product a single peak e.g. predict no. peaks in 13C-NMR spectrum of 1,3-dihydroxybenzene 4 environments = 4 peaks predict each carbon’s chemical shift this is the frequency of an atomic nucleus relative to TMS reference compound measured in ppm example- 13C-NMR spectrum for propanone both CH3 groups are in same environment 2 environments = 2 peaks C=O peak over 200 C-H peaks 0-50 Proton (1H) NMR spectroscopy Technique used to determine structure of molecules paired with other techniques like Mass spec Magnetic field strengths of protons in organic compounds measured and recorded on H NMR spectrum all samples measured against reference compound TMS / Tetramethylsilane single sharp peak at 0 ppm Sample peaks plotted as a ‘shift’ away from this reference peak gives rise to ‘chemical shift’ values for protons on the sample compound (measured in ppm) Features of NMR spectrum intensity of peak against chemical shift area under peak: no. protons in particular environment height: intensity / absorption from protons Molecular / chemical environments diff. arrangements of H atoms have diff environments (identical / symmetry = same environment) no. environments = no. diff chemical shifts / peaks e.g. How many different 1H chemical environments occur in 2-methylpropane? 2 1H chemical environments 2 peaks on 1H NMR spectrum Chemical shift values for H molecular environments symmetrical H = same environment 1 ppm → Alkane 2 ppm → Next to C=O 7 ppm → Benzene ring 9–10 ppm → Aldehyde 10–12 ppm → Carboxylic acid Low resolution 1H NMR peaks on a low resolution NMR spectrum refer to the molecular environments of an organic compound High resolution 1H NMR number of peaks a signal splits into = n + 1 n = number of H on adjacent C atom n+1 splitting patterns Common pairs of splitting patterns TMS and deuterated solvents TMS gives sharp peak at 0 on NMR spectrum why is TMS an ideal reference chemical? it is inert and volatile it reduces undesirable chemical reactions with compound analyses it mixes well with most organic compounds Deuterated solvents in 1H NMR CDCl3 used as a solvent, no peak why is a solvent needed for samples in 1H NMR? dissolving samples in solvent help separate molecules and prevent them from interacting what must the solvent do? be a good solvent for organic molecules not contain any H atoms, does not interfere with NMR signals examples of non-deuterated solvents Carbon tetrachloride, CCl4: This solvent does not contain hydrogen, so it does not produce 1H NMR signals. It is suitable for 1H NMR but does not dissolve all molecules well. examples of deuterated solvents Deuterated solvents are often used in 1H NMR because deuterium (²H) is an isotope of H whose nuclei absorb in a different region from protons, so it gives no signal in a ¹H NMR spectrum Deuterochloroform / Chloroform-d, CDCl3: preferred, contains deuterium (2H) instead of H, does not interfere with the H NMR Deuterium oxide / Heavy water, D2O: deuterium atoms exchange reversibly with the H in the -OH and -NH, signals identified in NMR Identifying -OH and -NH signals Protons in -OH (hydroxyl) and -NH (amine) groups give singlet peaks in ¹H NMR but these signals can be tricky: peaks are broad or sometimes fall outside normal chemical shift ranges H in these groups exchanges quickly with protons from water or acids, so only one peak appears Their chemical shift ranges may overlap with other types of protons To identify these groups more clearly, proton exchange with deuterium oxide (D2O) is used: The deuterium atoms in D2O exchange reversibly with the protons in the -OH or -NH groups -OH + D2O ⇌ -OD + HOD -NH-CO- + D2O ⇌ -ND-CO- + HOD Since deuterium does not absorb in the same region as protons in the NMR spectrum, the signal for -OH or -NH disappears after D2O is added This confirms the presence of -OH or -NH groups in the molecule If peak disappears after D2O, it is due to the exchange of a proton from an -OH or -NH group

Chalter 9: Chemical Control of Microbes (Phenol and the rest of it)

Chalter 9: Chemical Control of Microbes (Down to before Phenol)

Lab 6 - MSA, EMB, Phenol red

Ja, sehr gerne! Ich würde dir eine Französisch-Lernübersicht auf Matura-Niveau machen, die du direkt in eine Lernplattform kopieren kannst. Ich orientiere mich dabei an deinem Schulniveau und daran, dass du die Formen schnell lernen und dich anschliessend selbst abfragen können möchtest. Die Übersicht besteht aus drei Teilen: * Alle Zeitformen: Präsens, Passé composé, Imparfait, Plus-que-parfait, Futur simple, Conditionnel présent, Conditionnel passé und Subjonctif présent – jeweils mit Bildung, Hilfsverben und Beispielen. * Verben lernen: Die wichtigsten unregelmässigen Verben, ihre Stammformen und typische regelmässige Verben mit Besonderheiten. * Lernkarten und Quiz: So aufbereitet, dass du die Inhalte in eine Lernplattform übernehmen und dich damit abfragen lassen kannst. Wichtig: Bei den unregelmässigen Verben ist nicht nur das Präsens wichtig. Manche Verben haben beispielsweise einen unregelmässigen Stamm im Futur simple, aber eine ganz normale Endung. Genau diese Unterschiede nehme ich auf. 1. Die Zeitformen auf einen Blick Zeitform Bildung Présent Verbstamm + Präsensendungen Passé composé avoir/être im Präsens + participe passé Imparfait Stamm von nous im Präsens ohne -ons + -ais, -ais, -ait, -ions, -iez, -aient Plus-que-parfait avoir/être im Imparfait + participe passé Futur simple Infinitiv (bei -re ohne e) + -ai, -as, -a, -ons, -ez, -ont Conditionnel présent Futurstamm + Imparfait-Endungen Conditionnel passé avoir/être im Conditionnel présent + participe passé Subjonctif présent meistens Stamm von ils im Präsens ohne -ent + -e, -es, -e, -ions, -iez, -ent 1. Présent – Gegenwart Regelmässige Verben Person parler (-er) finir (-ir) vendre (-re) je parle finis vends tu parles finis vends il/elle/on parle finit vend nous parlons finissons vendons vous parlez finissez vendez ils/elles parlent finissent vendent Achtung: Nicht jedes Verb auf -ir funktioniert wie finir. Zum Beispiel wird partir zu nous partons, nicht nous partissons. 2. Passé composé – abgeschlossene Vergangenheit Bildung: avoir oder être im Présent + participe passé. * parler → j’ai parlé * finir → j’ai fini * vendre → j’ai vendu * aller → je suis allé(e) * partir → je suis parti(e) Die meisten Verben verwenden avoir. Einige Verben der Bewegung und reflexive Verben verwenden être. Bei être passt sich das participe passé normalerweise an Geschlecht und Anzahl an: elle est allée, ils sont allés. Wichtige unregelmässige participe-passé-Formen: Infinitiv Participe passé avoir eu être été faire fait prendre pris mettre mis voir vu lire lu écrire écrit dire dit ouvrir ouvert offrir offert pouvoir pu vouloir voulu devoir dû savoir su boire bu recevoir reçu venir venu naître né mourir mort 3. Imparfait – Gewohnheiten und Beschreibungen in der Vergangenheit Bildung: nous-Form im Présent ohne -ons + Imparfait-Endungen. Beispiel: nous parlons → parl- → je parlais. Person parler je parlais tu parlais il/elle/on parlait nous parlions vous parliez ils/elles parlaient Die Endungen sind immer gleich, auch bei unregelmässigen Verben. Die wichtige Ausnahme ist être → ét-: j’étais, tu étais, il était, nous étions, vous étiez, ils étaient. 4. Plus-que-parfait – Vorvergangenheit Bildung: avoir oder être im Imparfait + participe passé. * j’avais parlé * elle était partie * nous avions fini * ils s’étaient levés Es beschreibt etwas, das bereits geschehen war, bevor ein anderes Ereignis in der Vergangenheit eintrat. 5. Futur simple – Zukunft Bildung: Futurstamm + -ai, -as, -a, -ons, -ez, -ont. * parler → je parlerai * finir → tu finiras * vendre → il vendra * prendre → nous prendrons Bei Verben auf -re fällt das letzte -e weg: vendre → vendr-. 6. Conditionnel présent – würde-Form Bildung: Futurstamm + Imparfait-Endungen. * je parlerais * tu finirais * elle prendrait * nous irions * vous pourriez * ils seraient Bei vielen Verben ist der Stamm derselbe wie im Futur simple. Der Unterschied liegt in den Endungen: je parlerai (Futur) gegenüber je parlerais (Conditionnel). 7. Conditionnel passé – hätte/wäre-Form Bildung: avoir oder être im Conditionnel présent + participe passé. * j’aurais parlé * elle serait partie * nous aurions fait * ils auraient compris 8. Subjonctif présent Bildung: meistens Stamm der ils/elles-Form im Présent ohne -ent + -e, -es, -e, -ions, -iez, -ent. Beispiel parler: * que je parle * que tu parles * qu’il parle * que nous parlions * que vous parliez * qu’ils parlent Wichtige unregelmässige Formen: Infinitiv Subjonctif présent être que je sois, que nous soyons avoir que j’aie, que nous ayons aller que j’aille, que nous allions faire que je fasse, que nous fassions pouvoir que je puisse, que nous puissions savoir que je sache, que nous sachions vouloir que je veuille, que nous voulions venir que je vienne, que nous venions prendre que je prenne, que nous prenions Achte auf den Wechsel zwischen je und nous: Zum Beispiel que je vienne, aber que nous venions. 2. Die wichtigsten unregelmässigen Verben für die Matura Du musst nicht bei jedem Verb jede Form einzeln auswendig lernen. Am effizientesten ist es, pro Verb die wichtigsten Stämme und Sonderformen zu lernen. A. Die wichtigsten Verben im Présent Die Reihenfolge ist immer: je – tu – il/elle/on – nous – vous – ils/elles. Infinitiv Bedeutung Présent être sein suis, es, est, sommes, êtes, sont avoir haben ai, as, a, avons, avez, ont aller gehen vais, vas, va, allons, allez, vont faire machen fais, fais, fait, faisons, faites, font venir kommen viens, viens, vient, venons, venez, viennent tenir halten tiens, tiens, tient, tenons, tenez, tiennent prendre nehmen prends, prends, prend, prenons, prenez, prennent apprendre lernen apprends, apprends, apprend, apprenons, apprenez, apprennent comprendre verstehen comprends, comprends, comprend, comprenons, comprenez, comprennent mettre setzen/legen mets, mets, met, mettons, mettez, mettent dire sagen dis, dis, dit, disons, dites, disent lire lesen lis, lis, lit, lisons, lisez, lisent écrire schreiben écris, écris, écrit, écrivons, écrivez, écrivent voir sehen vois, vois, voit, voyons, voyez, voient croire glauben crois, crois, croit, croyons, croyez, croient boire trinken bois, bois, boit, buvons, buvez, boivent pouvoir können peux, peux, peut, pouvons, pouvez, peuvent vouloir wollen veux, veux, veut, voulons, voulez, veulent devoir müssen/sollen dois, dois, doit, devons, devez, doivent savoir wissen/können sais, sais, sait, savons, savez, savent connaître kennen connais, connais, connaît, connaissons, connaissez, connaissent recevoir erhalten reçois, reçois, reçoit, recevons, recevez, reçoivent vivre leben vis, vis, vit, vivons, vivez, vivent suivre folgen suis, suis, suit, suivons, suivez, suivent partir weggehen pars, pars, part, partons, partez, partent sortir hinausgehen sors, sors, sort, sortons, sortez, sortent dormir schlafen dors, dors, dort, dormons, dormez, dorment ouvrir öffnen ouvre, ouvres, ouvre, ouvrons, ouvrez, ouvrent mourir sterben meurs, meurs, meurt, mourons, mourez, meurent courir rennen cours, cours, court, courons, courez, courent rire lachen ris, ris, rit, rions, riez, rient plaire gefallen plais, plais, plaît, plaisons, plaisez, plaisent Besonders wichtig: être, avoir, aller, faire, venir, prendre, pouvoir, vouloir, devoir, savoir und dire. Diese solltest du wirklich sicher beherrschen. B. Unregelmässige Stämme im Futur simple und Conditionnel présent Diese Verben sind besonders wichtig, weil du den Stamm nicht einfach aus dem Infinitiv ableiten kannst. Infinitiv Futur-/Conditionnel-Stamm Beispiel Futur Beispiel Conditionnel être ser- je serai je serais avoir aur- j’aurai j’aurais aller ir- j’irai j’irais faire fer- je ferai je ferais venir viendr- je viendrai je viendrais tenir tiendr- je tiendrai je tiendrais pouvoir pourr- je pourrai je pourrais vouloir voudr- je voudrai je voudrais devoir devr- je devrai je devrais savoir saur- je saurai je saurais voir verr- je verrai je verrais envoyer enverr- j’enverrai j’enverrais recevoir recevr- je recevrai je recevrais courir courr- je courrai je courrais mourir mourr- je mourrai je mourrais falloir faudr- il faudra il faudrait pleuvoir pleuvr- il pleuvra il pleuvrait acquérir acquerr- j’acquerrai j’acquerrais Merksatz: Futur simple = Stamm + Zukunftsendung. Conditionnel présent = gleicher Stamm + Imparfait-Endung. C. Wichtige Verben mit unregelmässigem participe passé Diese Formen brauchst du im Passé composé, Plus-que-parfait und Conditionnel passé. Infinitiv Participe passé Beispiel être été j’ai été avoir eu j’ai eu faire fait j’ai fait dire dit j’ai dit écrire écrit j’ai écrit prendre pris j’ai pris apprendre appris j’ai appris comprendre compris j’ai compris mettre mis j’ai mis permettre permis j’ai permis voir vu j’ai vu boire bu j’ai bu lire lu j’ai lu croire cru j’ai cru pouvoir pu j’ai pu vouloir voulu j’ai voulu devoir dû j’ai dû savoir su j’ai su recevoir reçu j’ai reçu connaître connu j’ai connu vivre vécu j’ai vécu venir venu je suis venu(e) devenir devenu je suis devenu(e) revenir revenu je suis revenu(e) tenir tenu j’ai tenu ouvrir ouvert j’ai ouvert offrir offert j’ai offert souffrir souffert j’ai souffert naître né je suis né(e) mourir mort il est mort conduire conduit j’ai conduit traduire traduit j’ai traduit atteindre atteint j’ai atteint éteindre éteint j’ai éteint répondre répondu j’ai répondu perdre perdu j’ai perdu apprendre appris j’ai appris battre battu j’ai battu résoudre résolu j’ai résolu suivre suivi j’ai suivi Achte darauf, dass ähnliche Verben oft ähnliche Formen haben: prendre → pris, comprendre → compris, apprendre → appris. 3. Regelmässige Verben und Verben mit Besonderheiten Neben den wirklich unregelmässigen Verben solltest du diese Gruppen kennen. Gruppe Infinitiv Besonderheit / Beispiel -er parler meistens regelmässig: je parle -ir finir -iss- bei nous/ vous/ ils: nous finissons -re vendre meistens regelmässig: je vends -ger manger zusätzliches e: nous mangeons -cer commencer c wird zu ç: nous commençons -yer envoyer y → i in vielen Formen: j’envoie -yer payer je paie oder je paye -eler appeler Verdopplung: j’appelle -eter jeter Verdopplung: je jette -eler geler je gèle -eter acheter j’achète -é + Konsonant + er préférer je préfère, nous préférons -é + Konsonant + er répéter je répète, nous répétons -ir partir kein -iss-: nous partons -ir dormir Stamm verändert sich: je dors, nous dormons -ir ouvrir Endungen ähnlich wie bei -er: j’ouvre, vous ouvrez Auch diese Verben solltest du kennen: essayer, employer, nettoyer, appeler, rappeler, acheter, lever, mener, espérer, céder, protéger, partager, lancer. 4. Subjonctif: weitere wichtige unregelmässige Formen Infinitiv je/il-Form nous-Form être que je sois que nous soyons avoir que j’aie que nous ayons aller que j’aille que nous allions faire que je fasse que nous fassions pouvoir que je puisse que nous puissions savoir que je sache que nous sachions vouloir que je veuille que nous voulions venir que je vienne que nous venions tenir que je tienne que nous tenions prendre que je prenne que nous prenions boire que je boive que nous buvions devoir que je doive que nous devions recevoir que je reçoive que nous recevions voir que je voie que nous voyions croire que je croie que nous croyions mourir que je meure que nous mourions falloir qu’il faille keine normale nous-Form pleuvoir qu’il pleuve keine normale nous-Form Die Endungen sind normalerweise -e, -es, -e, -ions, -iez, -ent. Einige Verben haben zwei verschiedene Stämme, beispielsweise venir: que je vienne, aber que nous venions. 5. Lernkarten zum direkten Kopieren Du kannst diesen Abschnitt in eine Lernplattform einfügen, die Text in Karteikarten umwandeln kann. Jede Zeile enthält eine Frage und eine Antwort, getrennt durch einen Tabulator. Französisch Matura – Zeitformen und unregelmässige Verben Wie bildet man das Passé composé? Présent von avoir/être + participe passé. Wie bildet man das Imparfait? Nous-Form im Présent ohne -ons + -ais, -ais, -ait, -ions, -iez, -aient. Wie bildet man das Plus-que-parfait? Imparfait von avoir/être + participe passé. Wie bildet man das Futur simple? Futurstamm + -ai, -as, -a, -ons, -ez, -ont. Wie bildet man das Conditionnel présent? Futurstamm + Imparfait-Endungen. Wie bildet man das Conditionnel passé? Conditionnel présent von avoir/être + participe passé. Wie bildet man den Subjonctif présent? Meistens Stamm von ils ohne -ent + -e, -es, -e, -ions, -iez, -ent. Was ist der Imparfait-Stamm von être? ét-. Was ist der Futurstamm von être? ser-. Was ist der Futurstamm von avoir? aur-. Was ist der Futurstamm von aller? ir-. Was ist der Futurstamm von faire? fer-. Was ist der Futurstamm von venir? viendr-. Was ist der Futurstamm von pouvoir? pourr-. Was ist der Futurstamm von vouloir? voudr-. Was ist der Futurstamm von devoir? devr-. Was ist der Futurstamm von savoir? saur-. Was ist der Futurstamm von voir? verr-. Was ist das participe passé von être? été. Was ist das participe passé von avoir? eu. Was ist das participe passé von faire? fait. Was ist das participe passé von prendre? pris. Was ist das participe passé von mettre? mis. Was ist das participe passé von voir? vu. Was ist das participe passé von lire? lu. Was ist das participe passé von écrire? écrit. Was ist das participe passé von boire? bu. Was ist das participe passé von pouvoir? pu. Was ist das participe passé von vouloir? voulu. Was ist das participe passé von devoir? dû. Was ist das participe passé von savoir? su. Was ist das participe passé von venir? venu. Was ist das participe passé von naître? né. Was ist das participe passé von mourir? mort. Wie lautet der Subjonctif von être mit je? Que je sois. Wie lautet der Subjonctif von avoir mit je? Que j’aie. Wie lautet der Subjonctif von aller mit je? Que j’aille. Wie lautet der Subjonctif von faire mit je? Que je fasse. Wie lautet der Subjonctif von pouvoir mit je? Que je puisse. Wie lautet der Subjonctif von savoir mit je? Que je sache. Wie lautet der Subjonctif von vouloir mit je? Que je veuille. Wie lautet der Subjonctif von venir mit je? Que je vienne. Wie lautet die nous-Form von manger im Présent? Nous mangeons. Wie lautet die nous-Form von commencer im Présent? Nous commençons. Wie lautet die nous-Form von finir im Présent? Nous finissons. Wie lautet die nous-Form von partir im Présent? Nous partons. Was ist der Unterschied zwischen Futur simple und Conditionnel présent? Futur: Futurstamm + Zukunftsendungen. Conditionnel: Futurstamm + Imparfait-Endungen. Wie bildet man das Imparfait von être? J’étais, tu étais, il était, nous étions, vous étiez, ils étaient. Wie bildet man das Passé composé von aller? Je suis allé(e). Wie bildet man das Plus-que-parfait von faire? J’avais fait. Wie bildet man das Conditionnel passé von prendre? J’aurais pris. Wie bildet man das Futur simple von venir? Je viendrai. Wie bildet man das Conditionnel présent von pouvoir? Je pourrais. 6. Welche kostenlose Lernplattform empfehle ich? Ich würde dir diese zwei Optionen empfehlen: * Knowt – . Ähnlich wie Quizlet, mit Karteikarten und verschiedenen Lernmodi. Viele Funktionen gibt es gratis, wobei KI-Funktionen begrenzt sein können. * Anki – . Sehr gut, wenn du langfristig lernen möchtest. Am Computer und auf Android kostenlos; die offizielle iPhone-App ist kostenpflichtig. Mein Tipp: Probiere zuerst Knowt aus, weil du dich damit unkompliziert abfragen kannst. Kopiere die Lernkarten hinein und übe zuerst die Zeitformen, dann die unregelmässigen Stämme und zuletzt die participe-passé-Formen. Und noch wichtig: Diese Übersicht deckt die zentralen Formen ab, aber was du für deine konkrete Matura genau können musst, hängt von euren Unterrichtsvorgaben ab. Wenn du mir deine Liste mit den geforderten Verben oder ein Foto eurer Grammatikübersicht schickst, kann ich sie exakt daran anpassen.

Alcohols, Phenols & Ethers

Chapter 17: Alcohols & Phenols

Substituted Phenols

Unit 7: Alcohols, Phenols and Ethers

Alcohols, Phenols, Thiols, Ethers, and Light Lecture Review