31 Organic Synthesis and Analysis

A set of vocabulary flashcards focused on organic synthesis routes, specific reagents (oxidising, reducing, dehydrating), and chemical tests for identifying functional groups based on AQA A Level Chemistry.

Target molecule

The specific molecule a chemist aims to synthesise through a calculated series of organic reactions.

Yield

A measure of the efficiency of the conversion of a starting material into a product and the atom economy of a process.

Carbon chain lengthening

A process that increases the length of the carbon chain by one atom, typically achieved by the reaction of cyanide ions ($CN^-$) with a halogenoalkane to form a nitrile.

Synthetic robots

Computer-controlled arrays of reaction tubes and syringes used in the pharmaceutical industry to rapidly produce a 'library' of related compounds.

Oxidising agents

Reagents like potassium dichromate (VI) ($K_2Cr_2O_7$) acidified with dilute sulfuric acid ($H_2SO_4$) used to convert primary alcohols to aldehydes or carboxylic acids, and secondary alcohols to ketones.

Sodium tetrahydridoborate (III) ($NaBH_4$)

A reducing agent that reduces polar unsaturated groups like $C=O$ but not non-polar ones like $C=C$, because it generates the nucleophile $H^-$.

Hydrogen with nickel catalyst ($H_2/Ni$)

A reducing system specifically used to reduce $C=C$ double bonds but not $C=O$ groups.

Tin and hydrochloric acid ($Sn/H^+$)

Reagents used to reduce a nitro group ($R-NO_2$) to an amine group ($R-NH_2$).

Dehydrating agents

Substances like heated aluminium oxide ($Al_2O_3$) or acid catalysts used to convert alcohols to alkenes via elimination reactions.

Alkene chemical test

Shaking a compound with bromine water; a positive result is indicated when the red-brown colour disappears.

Halogenoalkane chemical test

Warming with $NaOH(aq)$, acidifying with $HNO_3$, and adding silver nitrate ($AgNO_3(aq)$) to form a precipitate of silver halide ($AgX$).

Fehling's solution

A reagent that, when warmed with an aldehyde, changes from a blue colour to a red precipitate.

Tollens' solution

A reagent used to identify aldehydes; a positive test results in the formation of a silver mirror upon warming.

Carboxylic acid chemical test

Adding sodium hydrogencarbonate ($NaHCO_3(aq)$) to the compound, which results in bubbles of carbon dioxide ($CO_2$) if the functional group is present.