Benzoic acid is used for foods while benzoin resin is used - PowerPoint Presentation

Slide1

Benzoic acid is used for foods while benzoin resin is used in cosmetics, lotions and

soaps

Acetylsalicylic acid

Acetic acid +waterSlide2

Carboxylic acids

Aliphatic carboxylic acidsFormic acid pungent

true liqid mobilyAcetic acid colorless

vinegar

Tartaric acid solid crystalline Citric acid yellowish white odorlessSlide3

Aromatic carboxylic acids

Benzoic acid solid crystalline,

yellowish white odorlessSalicylic acid

Phthalic

acid solid flaky ,yellowish white odorlessSlide4

Ignition test

Aliphatic C.A: inflammable ,non luminous and no smokyAromatic C.A:

inflammable , luminous and smoky Appearance change:formic and acetic acid volatilization tartaric acid swelling up and

charring* citric acid melting and formation yellow resin*

blackening benzoic, salicylic, phthalic acid melting Slide5

Color flame:No change with allOdor:

Formic ,acetic acid : no changeTartaric, citric acid: burnt sugar odor.Benzoic ,

phthalic acid: irritant odor (suffocating).Salicylic acid: phenolic odor .Residue:No residue with all except

Tartaric acid : black residue. Citric acid: yellow stain.Slide6

Acid base testAcidity test:

Na2CO3 solution(

conc) + acid → warm → effervescent

Strong effervescent that means acid.Weak effervescent that means acidic.

Conc. Hcl test: when substance soluble in 10% NaOH that means acid .if add HcL

in same test tube

→

reprecipted

again

Slide7

Conc. HCLAcidity test

L.PH2O

acidsReppt

.

effervescentChange blue to red

Miscible

Formic

Acetic

Change blue to red

soluble

tartaric

citric

Not done

Insoluble in H2O ,

dil

HCL but soluble in 10%NaOH

benzoic

phthalic

salicylic

All strong acidSlide8

Preliminary test

Soda lime test:Formic and acetic acid: not done for solid only.Tartaric and citric acid: burnt sugar odor on hot.Benzoic and

phthalic acid: benzene odor on hot.Salicylic acid: phenolic odor on hot.Slide9

30%NaOH:The same result of soda lime FeCL

3:No reaction with all.Conc. H

2SO4:Formic and acetic acid: effervescent due to CO2 evolution on cold.Tartaric acid : effervescent and

heavy charring on hot.Citric acid: effervescent and

yellow stain after long time it blackening.benzoic, phthalic and salicylic acids: no reactionSlide10

General test

Neutral FeCL3:

1 ml of acids +2ml NH4OH→ heat until complete disapperance of ammonia odor then wait 2-3 min. to cooling then add 2-3 dps

of neutral FeCL3→

formic ,acetic acids: blood red color give brown if heat it.Tartaric, citric acids:

lemon yellow

color.

Benzoic,

phthalic

acids:

buff ppt.

Salicylic acid: no need to use NH4OH just salicylic +H2O +neutralFeCL3 to give violet color.Slide11

Differentiation tests

Acetic acid

Formic acid-Turbidity or whit ppt. (Hg2CL2)HgCL2:

HgCL2+acid (wait 5 min)-

Disappear violet color, form brown ppt. (manganus oxideAlkaline Kmno4: acid + Na2CO3 sol. +KMNO4

Fruity

or ripe apple odor

-

Esterfication

:

ethOH

+acid + Conc. H2SO4 heat then pour it onto H2OSlide12

Citric acid

Tartaric acidEff. And yellow stain

Eff. And charringConc. H2SO4: (hot)

Discoloration of violet color anf form white ppt.

-Denges: acid+ H2O+ denges reagent boiling (without cooling) + KMNO4

Phthalic

acid

Benzoic acid

Unstable

pink color

-

Phthaline

test:

Phenol+ acid +Conc. H2SO4 heat then pour it onto 10%

NaOHReddish brown color give green flourescence if dilute it with water

-Flourescence;Acid +

resercinol

+ Conc. H2SO4 heat then pour it onto 10%

NaOHSlide13

Salicylic acidEsterfication:

methanol+ saliucylic acid+ Conc H2SO4heat then pour it onto 10 ml of H2O

→ vicks odor of winter green oil due to methyl salicylate formation.Formaldehyde:Formaldehyde+ salicylic acid + Conc. H2SO4→ crimson red color on the wall.

Phthaline

test:Salicylic acid + phthalic unhydride +Conc. H2SO4 heat then pour it onto 10 ml of 10% NaOH

→ unstable pink color Slide14

IR locationCOOH stretching band at 1710 cm-1