Tuesday, September 9, 2008

Acrylic acid

The Merriam-Webster Dictionary has defined Acrylic Acid as:

"an unsaturated liquid acid C3H4O2 that polymerizes readily to form useful products (as constituents for varnishes and lacquers)".

Other names[2]:
1. 2-Propenoic Acid.

2. Glacial acrylic acid.
3. Propene acid
4. Vinylformic Acid.
5. Acroleaic Acid.
6. Ethylene carboxylic acid.
7. Acide acrylique (French). [3]
8. Acido acrilio (Spanish).
9. Kyselina akrylova(Czech).

Properties of Acrylic Acid:

1. Boiling Range is 143 C and m.p. is 13 C. [1]
2. Solubility at 25 C in Water (parts/100) is infinity.
3. Solubility of water at 25 C, (parts/100 monomer) is infinity.
4. Formula of Acrylic acid is CH2=CH-(C=O)-OH.
5. It is a colourless liquid. [2]
6. Its odor is Acrid and odor threshold is 0.1 ppm.
7. Its vapour pressure is 4 mmHg at 20 C.
8. Its refractive index is 1.4224.
9. Its density is 1.049 g/cc at 20 C.

Preparation of Acrylic Acid:[2]
(oxidation) (oxidation)
1: Propylene -----------------> acrolein -----------> Acrylic Acid.

2. Reppe Process:
( nickel halide salt )
Acetylene + Carbon Monoxide + Water ---------------------> Acrylic Acid + H2.

( Hydrolysis )
3. Acrylonitrile ----------------------> Acrylic Acid

Uses of Acrylic Acid: [2]
It is used in the manufacture of certain esters, resins and salts. The polymeric emulsions prepared from Acrylic Acid are used in the coatings for leather, in paints, polishes and adhesives, and in photographic emulsions. It is used for the formation of polyacrylic acid gels, which are a form of polyanionic hydrogels [4].

References:
[1] Encyclopedia of Chemical Processing and Design: Volume 39 - Pollution: Air: Costs: Part 1. Parameters for Sizing Systems to Polymers: Polyamides: Aliphatic
By John J. McKetta, William A. Cunningham

[2] Health Effect Assessments of the Basic Acrylates (Basic Acrylic Monomer Manufacturers Association) by Elizabeth K. Hunt
[4] Encyclopedia of Surface and Colloid Science, Second Edition (Eight-Volume Set) By Ponisseril Somasundaran, Published by CRC Press, 2006, ISBN 0849396050, 9780849396052, 822 pages.

Further Reading:
Acrylic Acid (Environmental Health Criteria)

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Tuesday, July 8, 2008

Carbomer

Carbomer is a type of molecule which is usually obtained by the insertion of Carbon units in a certain molecule. It is a polymer of acrylic acid crosslinked with a polyfunctional molecule or compound such alkyl ethers of sucrose and/or pentaerythritol. [1]

It is also referred to as polyacrylic or polyacrylate.

Types of Carbomers:
In the National Formulary, there are six types of carbomers' monographs:
1. Carbomers 910
2. Carbomers 934
3. Carbomers 934P (The suffix "P" shows that this is a highly purified product and can be used orally). [2]
4. Carbomers 940
5. Carbomers 941
6. Carbomers 1342 [1]

Properties of Carbomers:[2]
1. White powder (Fluffy)
2. Hygroscopic
3. Soluble in water
4. pH of 1% aquous dispersion is 2.5 to 3.0
5. Incompatible with phenol and resorcinol
6. Products of Carbomers are sensitive to light

Uses:
It is mostly used as a suspending agent in Pharmaceutical industry. They are also used as gelling agents at the concentration of 0.5 to 2.0 % in water. [1]

References:
[1]Page # 2444, Encyclopedia of Pharmaceutical Technology by James Swarbrick.

[2] 18.18, Part 4 Pharmaceutical necessities, A Practical Guide to Contemporary Pharmacy Practice by Judith E. Thompson and Lawrence Davidow.

Further Reading:
A Practical Guide to Contemporary Pharmacy Practice by Judith E. Thompson and Lawrence Davidow

The National Formulary X : Tenth Edition

Martindale: The Complete Drug Reference, 35th Edition: Book and CD-ROM Package

Remington: The Science and Practice of Pharmacy

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Monday, July 7, 2008

Macromolecular

Related to molecules having a large molecular mass may be in the range from thousnads to millions.
Biochemically, proteins, lipids, carbohydrates, nucleic acids, polysaccharides are included.

Imbibe

Absorb (water, solution etc.)