carboxylic acids and derivatives

they slightly dissociate/ionise when in solution

react with carbonates. forms CO2 as a gas and can bubble through limewater to confirm its presence. the reaction observes fizzing and bubbling – any reaction with c acid I’d slower because they are weak acids so barely donate protons

they have O-H bonds. difference in electronegativity and the high mass to charge ratio of H gives it a strong delta positive charge the lone pair of electrons on the O in H2O is attracted to it forming H bonds, due to imf as the chains get longer this solubility reduces

COO- but the double bond between C=O kinda spreads out so its more like O I (-ve) C –O the delocalised -ve charge cloud stabilises the ion

ACID STRENGTH IS BASED ON ITS CONJUGATE ASE, THE CARBOXYLATE ION • SHORTER CHAIN LENGTH - alkyl groups are elctron releasing - when there are longer chains there are more alkyl groups which push electron density onto COO- ion once it forms making it more negative, and less stable - so acid is less strong - acid is less likely to donate proton and become unstable • ELECTRONEGATIVE ATOMS IN CHAIN - they are electron withdrawing because of their electronegativity - so they take away e- density from COO- ion, make it less negative and more stable

esterification // is a reversible reaction: acid + alcohol <=> ester + water // conditions: conc H2SO4 (strong acid catalyst), heat under reflux very slow reaction, can have low yield bc reversible. which is why it must be under reflux (also esters are volatile). better way of making esters is by acylation (n.a.e) with acid anhydrides or acyl chlorides

__yl __oate -yl part derived from alcohol (how many Cs on the C-O side of the COO f group) -oate part derived from c acid (how many Cs on the C=O side of the COO f group)

the -OH from the acid and H from the alcohol react to form water So the C on the carbonyl group bonds to the O remaining on the alcohol

RCOOR O || R-C-O-R

used in food flavourings and perfumes because they are sweet smelling compounds they have low BPs and make good solvents for other polar molecules used in plasticisers (substance added to material to make it more flexible bc polymer chains can now move over eachother) to increases elasticity and softness of materials.

used to make rigid pvc (addition polymer (long chain molecule), alkene) more flexible. there are strong imfs between pvc molecule chains because large Mr means many electrons so strong VdWs, but plasticiser disrupts the layers weakening the IMFs plasticised pvc is used for cable wire insulation, clothing (waterproof and sport)

triglycerides, a type of lipid. these are esters because they are formed by the reaction between glycerol (propane123triol) and 3 fatty acids of variable chain length so vegetable oils and animal fats are esters of propane-1,2,3-triol (glycerol)

fats tend to have saturated fatty acid chains so chain is linear. so stronger IMFs oils tend to have unsaturated fatty acid chains so chain is bended, but bends only occur if Z isomerism. so weaker IMFs

triglyceride esters the H on all of its OH groups and the OH from the COOH group of three fatty acids react to form triglyceride esters AND don’t forget 3 waters

hydrolysis in acidic conditions to form an alcohol and a carboxylic acid (reverse of esterification) by adding water. is a reversible reaction so will shift to reactants side to decrease conc water, increasing yeild of reactants, thereby hydrolysing the ester hydrolysis in alkaline conditions to form carboxylate salt and alcohol. When done on triglyceride, known as saponification, carboxylate salts are hydrophilic and hydrophobic so grease and water mix

strong acid catalyst is needed for this reversible reaction simple reverse reaction, the backwards reaction to: an alcohol and c acid <=> ester and water conditions: - dilute strong acid - heat under reflux - lit just the backwards of alcohol + acid

WHAT HAPPENS ester and NaOH in aqueous solution (ratio 1:3) will react to form salt of fatty acids and glycerol. the triglyceride is hydrolysed to form glycerol and fatty acid chains which have COO- f group carboxylate instead of COOH. this reacts with the Na+ or whatever cation to form 3 salts of the fatty acid as well as the glycerol triglyceride+ 3NaOH -> 3salts of fatty acid and glycerol (OH- bonds with glycerol that doesn’t have any of its OH groups) CONDITIONS boiled with metal hydroxide as reagent excess NaOH ensures ester hydrolysis USE the fatty acid salts are used as soaps because they have hydrophilic and hydrophobic properties. so grease and water can mix

renewable biofuel derived from biological sources like vegetable oils, animal fats or recycled greases it is a mixture of methyl esters of long chain carboxylic acids

vegetable oils and methanol in presence of KOH (strong alkali) catalyst • lipid is broken down into 3 fatty acids and glycerol by reaction with KOH • these fatty acids are converted into three new ester using methanol. methanol reacts with fatty acids to form methyl (__oate (depends on formula of long chain fatty acids)) esters. • overall the KOH is not used up and so acts as a catalyst

no net release of carbon dioxide to the atmosphere because the same amount of CO2 released when the fuel is burned is absorbed from the crops it was made from during photosynthesis its production uses a lot of farmland instead of using it for food production

functional group O I I R-C-Cl , always at the end of a molecule suffix is always -oyl chloride HCl - - - white misty fumes! crazy right Cl

add acidified silver nitrate chloride leaves acyl chloride as an ion, and forms a white ppt when ionically bons to silver Ag+ (aq) + Cl- (aq) –> AgCl (s)

acylation: replacing a H atom on a molecule with an acyl group (RCO) nucleophilic addition elimination

acyl chlorides (and acid anhydries) contain a polar C=O bond and a strongly electronegative Cl atom so the C is delta +ve. so susceptible to attack by: water ——— carboxylic acid ammonia ———- amide 1y amine ———- N substituted amide (one of the Hs in NH2 is smth else) alcohols ——- ester they all have a LP on the O or N. therefore they can act as nucleophiles