Epithermal Deposits

Endothermic and Exothermic reaction examples

Ectotherms

Endotherms

Exothermic and Endothermic reactions

Exothermic and endothermic reactions

Endotherm and ectotherm graph interpretation

Ectotherm performance and classification

Exothermic + endothermic reactions

Exothermic and Endothermic

Definitions of endothermic and exothermic

O2 O3 X2 H2O2 NaOCl CrO3 or any Cr2 PCC KMnO4 OsO4 Ag2O HClO4 HIO4 Reducing Agents H2 Li Na K NaBH4 LiAlH4 Reduction of alkynes to trans alkenes Na and liq. NH3 (sometimes with EtOH) Two Hs added to opposite sides of alkene Reduction of Alkynes to Cis alkenes H2 and Lindlar's catalyst (Pd, quinoline, CaCO3, Pb(OAC)2) Two Hs added to same side of alkene Alkynes are more reactive than alkenes and Lindlar’s is too weak for alkenes Reduction of alkenes to alkanes (Catalytic Hydrogenation) H2 excess, catalyst (Ni, Pd, Pt, Pd/C) Exothermic Always syn addition of Hs Reduction of alkynes to alkanes (Catalytic Hydrogenation) H2 excess, catalyst (Ni, Pd, Pt) 4 Hs added Stability of Alkenes More substituted is more stable Trans is more stable than cis Reduction of alkyl halides to alkanes w/LAH Also written LiAlH4 SN2 rxn X is substituted with H X = I > Br > Cl (not F) Rate of rxn : Me > 1 > 2 (not 3) Epoxidation of alkenes w/ Peracids Alkene forms epoxide Rxn is stereospecific (if it starts cis the epoxide ends in cis) Weakest O-H bond from peroxide moves 1 step rxn no intermediate Common peracids: MCPBA and MMPP Oxidative Cleavage of Alkenes O3 H2O, CH3SCH3, PPh3 Cut in half at alkene and add =O to make aldehyde or ketones Oxidative cleavage of Alkynes (Ozonolysis) O3 H2O, CH3SCH3, PPh3 Internal Alkyne: cut in half and make two carboxylic acids Terminal Alkyne: cut in half and make carboxylic acid and CO2 PCC Oxidation (Pyridinium chlorochromate) Soluble in organic solvent Stops at aldehyde and doesn't go to COOH even with primary OH O becomes double bonded and H attaches to C Oxidation of Alcohols Primary [O] aldehyde [O] carboxylic acid Secondary [O] ketone Tertiary [O] no rxn [O] conditions: Na2Cr2O7 or K2Cr2O7 over H2SO4, H2O And H2CrO4 over acetone (jones reagent) Anti - 1,2 - dihydroxylation Peracid H+ or OH- in H2O OH added to opposite sides of C-C bond First peracid makes an epoxide where R1 and R3 stay cis so dashed Then second step opens ring with OH on straight bonds If cyclo then racemic mixture of OH on dashed and wedged Syn - 1,2 - dihydroxylation 3 conditions: Cold KMnO4 over OH- and H2O Cat OsO4, NMO 2) NaHSO3, H2O OsO4 2) NaHSO3, H2O OH added to straight bonds on same side of C-C bond Needs to be rotated 180 for final product where OH is across from each other Chapter 13 Breaking into radicals : homolytic cleavage and endothermic Radicals are sp3, trigonal planar, 120, empty p-orbital Most stable to least stable: 3 > 2 > 1 > methyl Why? Hyperconjugation (R groups stabilize radical C) Induction (electrons flow from sp3 C to sp2 C) How do radicals react Radicals attack sigma bonds: radical hits bond and takes H Radicals attack pi bonds: radical hits bond and attaches to C Radicals attack radicals: coupling exothermic Alkanes w/ Halogens Exothermic R-H + X2 with light and heat makes R-X + HX X2 is either Cl or Br Alkane w/ Cl2 Initiation: Cl-Cl breaks to two Cl rad Propagation: Cl rad + alkane making Cl-H and alkane rad Alkane rad + Cl-Cl making alkane with one less H and Cl attached Chlorination of Higher Alkanes Cl2 with light heat # of signals is types of products Not very regioselectivity Bromination of Higher Alkanes Br2 with light heat Very regioselective Br goes to most sub C Radical Stability Allylic radical > 3 > 2 > 1 > me > vinyl =. Stereochemistry of radical Halogen Cl rad + alkane Cl & Br can be added to top or bottom on straight bond creating enantiomers or diasteromers Allylic Substitution If it is alkene + X2 at high concentration, low temp over a non polar solvent then it is a vicinal dihalide ( X to both previous alkene Cs) If it is alkene + X2 at low concentration, high temp then one X subs on sp3 C attached to double bond and the bond stays and HX is made

Exothermic and endothermic reactions

Endothermic & Exothermic Reactions

Thermoregulation In Endotherms

Exothermic and Endothermic Reactions

5: Endothermic and exothermic

Thermoregulation In Ectotherms

Temperature regulations in ectotherms (behavioural/physiological)

Warming up in endotherms