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Chemistry > 3.3.9 Carboxylic acid and esters and derivatives > Flashcards

3.3.9 Carboxylic acid and esters and derivatives Flashcards

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1
Q

What are the products from the reaction of carboxylic acids and carbonates?

A

R-oate, water, carbon dioxide

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2
Q

Carboxylic acids are weak acids, what does this mean and what does it produce?

A

they dissociate partially to form H+ ions and a carboxylate ions

carboxylic acid <—-> carboxylate ion + H+

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3
Q

How do you make an ester?

A

Reacting ALCOHOL with CARBOXYLIC ACID or ACID ANHYDRIDES

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4
Q

Whats the difference in forming esters with carboxylic acid and acid anhydride?

A

COOH = need sulfuric acid catalyst , forms water as a product
anhydride = no catalyst, forms carboxylic acid as a product

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5
Q

What functional group do esters have?

A

-COO-

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6
Q

How do you name an ester

A
  1. part of ester formed from alcohol is alkyl group (attached to the COO part. this is named FIRST
  2. the part of the ester formed from the carboxylic acid remains the same but change the suffix from -oic acid to -oate. this is named SECOND

find an example

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7
Q

What are 3 common uses of esters (commercially/industrial process)?

A
  • perfume and food flavourings
    some have sweet smells to be used in fragrances or food products
  • solvents
    esters are polar so other polar compounds will dissolve readily in esters
    they also have low bpt and evaporate easily, valuable in making glues
  • plasticisers
    esters used to make plastics more flexible during polymerisation process
    they can leach out of plastic over time and plastic does become brittle
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8
Q

How can you speed up hydrolysis of ester?

A

using an acid (acid hydrolysis)
using a base (base hydrolysis)

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9
Q

What do you form during hydrolysis of an ester?

A

carboxylic acid and alcohol

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10
Q

Describe the process of acid hydrolysis on an ester

A

use a diluted acid (sufuric or hydrochloric acid) to split ester into carboxylic acid and alcohol

reaction is conducted under reflux

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11
Q

What happens if more water is added to hydrolysis of an ester?

A

equilibrium shifts to the right, so more product is produced

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12
Q

Describe the process of base hydrolysis on an ester

A

use a dilute base (sodium hydroxide) (OH-) to split an ester into CARBOXYLATE ION and ALCOHOL

reaction conducted under reflux

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13
Q

What do you produce when you react glycerol (alcohol) and fatty acid (carboxylic acid)

A

an ester which makes fats and oils

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14
Q

What is the other name for glycerol?

A

Propane-1,2,3-triol

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15
Q

give an example of an unsaturated oil ester

A

vegetable oil

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16
Q

How does vegetable oil/any oil being unsaturated affect its characteristics?

A

as they are unsaturated, their hydrocarbon chains arent straight so the chains cant pack together closely and hence they have LOWER VAN DER WAALS forces.
(has cis/trans)

so they have LOWER MPT and are liquids at room temperature

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17
Q

How does fat being unsaturated affect its characteristics?

A

as they are saturated, their hydrocarbon chains are straight and more uniform than oils which means the chains can pack together closely and hence have much HIGHER VAN DER WAALS forces.
(no cis/trans)

they have HIGHER MPT and are sold at room temp

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18
Q

How do you make soap from animal fats or vegetable oil?

A

hydrolyse by heating them with sodium hydroxide

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19
Q

give the work equation for the production of soap from fat

A

fat + 3 sodium hydroxide —> glycerol + 3 sodium salt (soap)

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20
Q

How do you generate biodiesel?

A

vegetable oil is converted into biodiesel as it reacts with methanol and potassium hydroxide as a catalyst

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21
Q

what is biodiesel?

A

a mixture of fatty acids made from methyl esters

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22
Q

what is the word equation for production of biodiesel?

A

oil + methanol ——–> glycerol + methyl ester
(KOH)

23
Q

What is the functional group of acyl chlorides?

A

-COCL

24
Q

how do you name an acyl chloride

A

find the longest chain and add -oyl chloride to the end

(acyl group is always on carbon 1)

25
Q

how do you name an acyl chloride

A

find the longest chain and add -oyl chloride to the end

(acyl group is always on carbon 1)

26
Q

What are the 4 compounds that react with acyl chlorides?

A

water, ammonia, primary amines, alcohol

27
Q

what do acyl chlorides react with water to form + work equation

A

they form carboxylic acids

acyl chloride + water —> -oic acid + HCL

28
Q

What are the features of HCL gas

A

white misty fumes

29
Q

Why is the production of carboxylic acids from acyl chlorides very vigorous?

A

there is a very strong delta postive carbon Aton (due to it being double bonded to an oxygen atom) hence the lone pairs of electrons on the oxygen atom on water readily attacks the carbon atom

30
Q

What does a reaction between acyl chloride and ammonia produce + word equation

A

amides

acyl chloride + ammonia —-> amide + HCL

31
Q

What is the difference between a amide and amine?

A

Amide have -O=C-NH2

Amines only have -NH2

32
Q

What does a reaction between alcohol and ACYL CHLORIDES produce + word equation?

A

ester

acyl chloride + alcohol —-> ester + HCL

33
Q

What does a reaction between acyl chlorides and primary amines produce + word equation?

A

N- substituted amide

acyl chloride + primary amine —-> N- substituted amine + HCL

34
Q

What are acid anhydrides made from

A

2 of the same carboxylic acids (joined by an oxygen atom(symmetrical))

35
Q

How do you name acid anhydrides

A

find the carboxylic acid its made from, then remove -acid and replace with -anyhydride

e.g ethanoic anhydride

36
Q

What differs/ similar between the reaction of acyl chlorides and acid anhydrides with water, ammonia, alcohol and primary amines?

A

whilst they both produce retrospective products of carboxylic acid, amide, ester and n-substitudted amide

acyl chlorides produce an addition produce of HCL
whilst acid anhydrides produce an additional product of a carboxylic acid

37
Q

What reaction do acyl chlorides undergo when reaction with alcohols, amides, primary amines, ammonia?

A

nucelpphillic addition-elimination

38
Q

Draw the mechanism for propanoyl chloride and methanol

A
39
Q

What is aspirin made from?

A

it is an ester made by reaction ETHANOIC ANHYDRIDE OR ETHANOYL CHLORIDE WITH SALICYLIC ACID

40
Q

Why is ethanoic anhydride used instead of ethanoyl chloride in industry?

A
  • safer as its less corrosive

-safe as it doesnt react vigorously with water

-does not produce harmful HCL gas

-cheaper

41
Q

What is the name of the condenser used in reflux

A

liebig condenser

42
Q

when is reflux used

A

when you want to strongly heat without losing volatile reactants and products

43
Q

How do we heat flammable liquids?

A

using a hot water bath or mantle (electric heater)

44
Q

When is distillation used

A

when you want to separate substances with different boiling points / when you want to extract a chemical before it reacts any further

45
Q

how should you heat your mixture when extracting a compound depending on the compounds bpt?

A

if my compounds has a lower bpt than the mixture, then heat it to the bpt of my compound so it can vaporise and condense out

if my compound has a higher bpt than the mixture, then heat it to the bpt of the mixture so that everything else besides my compound vaporises and condenses out and only my compound is left in the flask

46
Q

When is redistillation used

A

when we want to purify volatile substances which can be purified further using separation (which is another technique)

47
Q

When is separation used and how ?

A

to remove impurities that are dissolved in water

  • add products from distillation into separating funnel and add water to dissolve soluble impurities to form aqueous solution
  • wait for solution to settle forming 2 layers, top layer = impure product bottom layer = aqueous layer with water soluble impurities

-drain off the aqueous layer (remember to remove stopper)

-impure product inside separating funnel may still have insoluble impurities (egg water) so add anhydrous CaCl2 (dehydrating agent) and itll remove aqueous substances remaining

  • INVERT and leave for 20-30 mins
48
Q

How do you separate the clumps formed from anhydrous CaCl2 and the impure product?

A

use filtration

  • Buckner funnel and slightly dampened filter paper placed into flask with vacuum
  • vacuum crates reduced pressure in flask and pulls liquid through

-solid gets left in the Buckner funnel

49
Q

When is recrystallisation undergone

A

to purify solids

50
Q

Explain the process of recrystallisation

A
  • for example you have filtered the solid with a Buckner funnel
  • dissolve this solid is just enough HOT SOLVENT, now you have a saturated solution of your impure product
  • allow the solution to cool down, Crystals will begin to form
  • as there is a smaller quantity of impurities, these will crystallise a lot slower hence they’ll remain dissolved
  • FILTER to get your solid purified crystals and WASH with COLD SOLVENT and dry them off
51
Q

Why is the solvent chosen to dissolve your solid so important?

A

because you need your impure solid to DISSOLVE in HOT SOLVENT
and be virtually INSOLUBLE when it is cold

(If not your substance won’t dissolve in hot solvent and you can’t filter the purified solid in cold solvent if it is soluble in it)

52
Q

How do you find the bpt of your produced solution?

A
  • set up distillation and gently heat sample
  • measure temp at which it distills using the thermometer in the equipment

-compare this bpt temp to the data book values

(if impurities remain then the bpt will be higher the recorded value in book)

(various organic compounds have same bpt, need to use other analytical techniques to identify)

53
Q

how do you find the bpt of your produced solid

A
  • add sample of solid into a capillary tube and place into the HEATING ELEMENT of the melting point apparatus

-increase the temp until the substance starts to melt

-find the temp range of when the solid starts to melt and completely melts

  • compare melting point against data book values

(if substance contains impurities the mpt will be lower and temp range larger)

53
Q

how do you find the bpt of your produced solid

A
  • add sample of solid into a capillary tube and place into the HEATING ELEMENT of the melting point apparatus

-increase the temp until the substance starts to melt

-find the temp range of when the solid starts to melt and completely melts

  • compare melting point against data book values

(if substance contains impurities the mpt will be lower and temp range larger)

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