(MIDTERM) Extraction of Citric Acid Flashcards
The term “______________” is used to designate simple organic compounds containing not more than six carbon atoms and two or three carboxyl groups
plant acids
2-hydroxypropane-1,2,3-tricarboxylic acid
Citric Acid
Many of them functions as intermediates in cellular respiration and occur widely
in plant tissues in high concentration
plant acids
First isolated in crystal form from lemon juice
by ______________
Scheele in 1784
Formula of CITRIC ACID
- Molar Mass - Anhydrous
- Molar Mass - Monohydrate
Molar Mass - Anhydrous
192.12 g/mol
Molar Mass - Monohydrate
210.14 g/mol
Chemical Formula of Citric Acid
C6H8O7
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;
Citric Acid
Solubility: 1 g in 0.5 mL water, 2 mL alcohol,
and about 30 mL ether; freely soluble in
methanol
Citric Acid
In small quantities, citric acid is found in citrus fruits, especially ______________________
lemons and limes
In amounts exceeding 1% of the dry weight of the product, it is present in:
- Lemon (4-8%)
- Blackberries (1.5–3.0%)
- Grapefruits (1.2–2.1%)
- Oranges, Raspberries and
Strawberries (0.6–1.3%)
BLACKBERRIES sn
Rubus fruticosus
LEMON sn
Citrus limon
GRAPEFRUITS sn
Citrus paradisi
ORANGES sn
Citrus sinensis
RASPBERRIES sn
Rubus idaeus
STRAWBERRIES sn
Fragaria ananassa
Since about 1925 the acid has been produced largely by fermentation of
sucrose solution, including molasses, by fungi belonging to the ______________________ group
Aspergillus niger
At room temperature: a white crystalline powder
Citric Acid
Can exist either in an anhydrous form or as a monohydrate
Citric Acid
Anhydrous form crystallizes from __________________
hot water
Monohydrate forms when citric acid is crystallized from _____________
cold water
Monohydrate can be converted to the anhydrous form by __________
heating above 78°C
Citric acid dissolves in absolute (anhydrous) _____________
ethanol at 15°C
When heated above ____________, it decomposes through the loss of carbon dioxide and water.
175°C
Pharmacologic/Clinical Uses of Citric Acid
- 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)
___________ is one of the essential carboxylic acids in the Krebs cycle.
citric acid
- 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
Pharmaceutical Uses of Citric Acid
positively correlated with acidity, sour taste, citrus aroma and flavor,
and is negatively correlated with bitterness
Flavorant
Sodium citrate formation
(highly soluble)
Calcium citrate precipitation
(insoluble)
Citric acid regeneration
(soluble)
Crystallization
(solubility decrease)
- To 2 ml of sodium citrate solution, add 1ml of 5% calcium chloride
Sodium Citrate + Calcium Chloride → Calcium Citrate + Sodium Chloride
- 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.
Sodium Citrate + Lead Acetate → Lead Citrate + Sodium Acetate
Lead Citrate + Acetic Acid + Heat → Lead Acetate + Citric Acid
- 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)
- 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)
Sodium Citrate + Acetic Anhydride ——–Pyridine——> Citrate-Acetyl Esters
Add 0.5 mL or few mg of carboxylic acid + dilute NH4OH
NEUTRALIZATION TEST
NEUTRALIZATION TEST
On hot plate: ______________
until ammonia odor disappear
NEUTRALIZATION TEST
On cold: _____________
add one drop of Ferric Chloride
Results of NEUTRALIZATION TEST:
- Formic acid and acetic acid
- Tartaric acid and citric acid
- Benzoic acid and phthalic acid
- Salicylic acid (directly without add NH4OH)
Formic acid and acetic acid gives _______________
red blood color
Tartaric acid and citric acid gives _________________
lemon yellow color
Benzoic acid and phthalic acid gives ________________
buff precipitate
Salicylic acid (directly without add NH4OH) gives _____________
violet color
