15C.2 Flashcards

1
Q

how can we obtain carboxylic acid using oxidation

A

by oxidizing a primary alcohol or aldehyde using potassium dichromate(VI) and heat under reflux (with primary alcohol first forming an aldehyde) then fractionally distill the reaction mixture to obtain a purse sample of carboxylic acid

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2
Q

what is the oxidation reaction for aldehydes and primary alcohols into carboxylic acid

A

page 124

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3
Q

what are nitriles

A

organic compounds containing the CN group

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4
Q

what are the two ways you can obtain pure carboxylic acid

A
  1. oxidation of an aldehyde or a primary alcohol with a potassium dichromate (VI) heating under reflux
  2. hydrolysis of a nitrile by heating under reflux with dilute acid or aqueous alkali
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5
Q

how can we get a carboxylic acid from hydrolysis

A

by heating a nitrile under reflux with either a dilute acid or a aqueous alkali and the carboxylic acid is distilled through fractional distillation, where the C N triple bond breaks and nitrogen from ammonia or an ammonium ion ( note with aq alkali a carboxylate ion is formed but that can be formed in a carboxylic acid by just adding dilute acid)

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6
Q

what are the hydrolysis reactions of nitriles

A

page 124

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7
Q

what are the four main reactions that carboxylic acid undergoes

A
  1. reduction
  2. neutralization
  3. halogenation
  4. esterification
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8
Q

what does the reduction of carboxylic acids from

A

primary alcohol

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9
Q

why doesn’t the reduction of carboxylic acid from aldehyde

A

because aldehydes are more easily reduced compared to carboxylic acid so any aldehyde formed during the reaction will be immediately reduced to a primary alcohol

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10
Q

what is the reducing regent used in reduction of carboxylic acid

A

lithium aluminium hydride LiAlH4 and is used in a solvent of dry ether

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11
Q

what is the reduction equation for reduction of carboxylic acid

A

page 124

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12
Q

how can we neutralized a carboxylic acid

A

even through there week acids they can be completely neutralized using aq alkali

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13
Q

what are the products of neutralization of carboxylic acid

A

carboxylate salt and water

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14
Q

what are the uses of sodium ethanoate

A
  1. hand warmers
  2. additive that give the salt and vinegar flavor for potato chips
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15
Q

what is the equation of the neutralization of sodium ethanoate

A

page 125

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16
Q

what are the carboxylate salt general formula

A

RCOONa and since there ionic it can be RCOO^-Na^+

17
Q

how does the halogenation of carboxylic acid occurs

A

the OH group is replaced by a halogen forming acyl chlorides (COCl), HCl, and phosphorus trichloride oxide (POCl) which is a liquid that mixes with the the acyl so we use fractional distillation to get the acyl

18
Q

what are acyl chlorides

A

they are highly reactive organic compounds made from the halogenation of carboxylic acids and they have the functional group of COX

19
Q

what is the regent used in the halogenation of carboxylic acids

A

phosphorus(V) chloride ( phosphorus pentachloride)

20
Q

why do we carry out halogenation of carboxylic acids in anhydrous conditions

A

because both the regent and the product of acyl chloride can react with water

21
Q

why is heating not required in halogenation of carboxylic acids

A

because it is a very vigorous reaction

22
Q

what is the suffix for acyl chloride

A

oyl chloride

23
Q

what is the chemical equation for that halogenation of carboxylic acids

24
Q

what happens during esterification

A

carboxylic acid reacts with alcohol and a small amount of acid catalyst (often concentrated sulfuric acid) to form an ester and water

25
even with a catalyst esterification is
slow and reversible
26
what are the uses of esters
1. solvents 2. make polymers (polyesters) 3. responsible for the smells of fruit 4. most animal fats 5. most vegetable oil
27
how do we name an ester
first is the alkali group from the alcohol then the carboxylate from the carboxylic acid for example ethyl methanoate
28
what is the chemical equation for esterification
page 125