(MIDTERM) Extraction of Citric Acid

Question 1

The term “______________” is used to designate simple organic compounds containing not more than six carbon atoms and two or three carboxyl groups

Answer 1

plant acids

Question 2

2-hydroxypropane-1,2,3-tricarboxylic acid

Answer 2

Citric Acid

Question 3

Many of them functions as intermediates in cellular respiration and occur widely
in plant tissues in high concentration

Answer 3

plant acids

Question 4

First isolated in crystal form from lemon juice
by ______________

Answer 4

Scheele in 1784

Question 5

Formula of CITRIC ACID

Answer 5

• Molar Mass - Anhydrous
• Molar Mass - Monohydrate

Question 6

Molar Mass - Anhydrous

Answer 6

192.12 g/mol

Question 7

Molar Mass - Monohydrate

Answer 7

210.14 g/mol

Question 8

Chemical Formula of Citric Acid

Answer 8

C6H8O7

Question 9

Colorless, translucent crystals,
or a white, granular to fine crystalline powder;
odorless; strongly acid taste; the hydrous
form effloresces in moderately dry air but is
slightly deliquescent in moist air; loses its
water of crystallization at about 50°C;

Answer 9

Citric Acid

Question 10

Solubility: 1 g in 0.5 mL water, 2 mL alcohol,
and about 30 mL ether; freely soluble in
methanol

Answer 10

Citric Acid

Question 11

In small quantities, citric acid is found in citrus fruits, especially ______________________

Answer 11

lemons and limes

Question 12

In amounts exceeding 1% of the dry weight of the product, it is present in:

Answer 12

• Lemon (4-8%)
• Blackberries (1.5–3.0%)
• Grapefruits (1.2–2.1%)
• Oranges, Raspberries and
  Strawberries (0.6–1.3%)

Question 13

BLACKBERRIES sn

Answer 13

Rubus fruticosus

Question 14

LEMON sn

Answer 14

Citrus limon

Question 15

GRAPEFRUITS sn

Answer 15

Citrus paradisi

Question 16

ORANGES sn

Answer 16

Citrus sinensis

Question 17

RASPBERRIES sn

Answer 17

Rubus idaeus

Question 18

STRAWBERRIES sn

Answer 18

Fragaria ananassa

Question 19

Since about 1925 the acid has been produced largely by fermentation of
sucrose solution, including molasses, by fungi belonging to the ______________________ group

Answer 19

Aspergillus niger

Question 20

At room temperature: a white crystalline powder

Answer 20

Citric Acid

Question 21

Can exist either in an anhydrous form or as a monohydrate

Answer 21

Citric Acid

Question 22

Anhydrous form crystallizes from __________________

Answer 22

hot water

Question 23

Monohydrate forms when citric acid is crystallized from _____________

Answer 23

cold water

Question 24

Monohydrate can be converted to the anhydrous form by __________

Answer 24

heating above 78°C

Question 25

Citric acid dissolves in absolute (anhydrous) _____________

Answer 25

ethanol at 15°C

Question 26

When heated above ____________, it decomposes through the loss of carbon dioxide and water.

Answer 26

175°C

Question 27

Pharmacologic/Clinical Uses of Citric Acid

Answer 27

* For living organisms, citric acid is one of the essential carboxylic acids in the Krebs cycle. * Used to dissolve urinary bladder calculi * Dialysis * Mild astringent * Anticoagulant (citrate)

Question 28

___________ is one of the essential carboxylic acids in the Krebs cycle.

Answer 28

citric acid

Question 29

* Preparation of: - Anticoagulant Citrate Dextrose Solution - Anticoagulant Citrate Phosphate Dextrose Solution - Citric Acid Syrup - Effervescent Salts (with Tartaric Acid and Sodium Bicarbonate) * pH regulator * Excipient in lyophilized formulations * Stabilizing agent * Flavorant - positively correlated with acidity, sour taste, citrus aroma and flavor, and is negatively correlated with bitterness

Answer 29

Pharmaceutical Uses of Citric Acid

Question 30

positively correlated with acidity, sour taste, citrus aroma and flavor, and is negatively correlated with bitterness

Answer 30

Flavorant

Question 31

Sodium citrate formation

Answer 31

(highly soluble)

Question 32

Calcium citrate precipitation

Answer 32

(insoluble)

Question 33

Citric acid regeneration

Answer 33

(soluble)

Question 34

Crystallization

Answer 34

(solubility decrease)

Question 35

1. To 2 ml of sodium citrate solution, add 1ml of 5% calcium chloride

Answer 35

Sodium Citrate + Calcium Chloride → Calcium Citrate + Sodium Chloride

Question 36

2. To 2 ml of sodium citrate solution, add 1 ml of 5% lead acetate solution. Allow the precipitate to settle and decant the supernatant liquid. To the precipitate, addequal amount of acetic acid and warm.

Answer 36

Sodium Citrate + Lead Acetate → Lead Citrate + Sodium Acetate Lead Citrate + Acetic Acid + Heat → Lead Acetate + Citric Acid

Question 37

* To 15 ml of pyridine, add a few mg of a citrate salt dissolved or suspended in 1ml of water, and shake. To this mixture add 5ml of acetic anhydride and shake. * Positive Result: _________________

Answer 37

Light Red Color (presence of citrates)

Question 38

* To 15 ml of pyridine, add a few mg of a citrate salt dissolved or suspended in 1ml of water, and shake. To this mixture add 5ml of acetic anhydride and shake. * Positive Result: Light Red Color (presence of citrates)

Answer 38

Sodium Citrate + Acetic Anhydride --------Pyridine------> Citrate-Acetyl Esters

Question 39

Add 0.5 mL or few mg of carboxylic acid + dilute NH4OH

Answer 39

NEUTRALIZATION TEST

Question 40

NEUTRALIZATION TEST On hot plate: ______________

Answer 40

until ammonia odor disappear

Question 41

NEUTRALIZATION TEST On cold: _____________

Answer 41

add one drop of Ferric Chloride

Question 42

Results of NEUTRALIZATION TEST:

Answer 42

* Formic acid and acetic acid * Tartaric acid and citric acid * Benzoic acid and phthalic acid * Salicylic acid (directly without add NH4OH)

Question 43

Formic acid and acetic acid gives _______________

Answer 43

red blood color

Question 44

Tartaric acid and citric acid gives _________________

Answer 44

lemon yellow color

Question 45

Benzoic acid and phthalic acid gives ________________

Answer 45

buff precipitate

Question 46

Salicylic acid (directly without add NH4OH) gives _____________

Answer 46

violet color