BENZOIN

PRODUCT IDENTIFICATION
CAS NO. 119-53-9

BENZOIN

EINECS NO. 204-331-3
FORMULA C6H5CH(OH)COC6H5
MOL WT.

212.25

H.S. CODE 2914.49
TOXICITY Oral rat LD50: 10 gm/Kg
SYNONYMS 2-Hydroxy-2-phenylacetophenone;
2-Hydroxy-1,2-Diphenylethanone; Alpha-hydroxybenzyl phenyl ketone; DL-Benzoin;
SMILES

 

CLASSIFICATION

 
 

PHYSICAL AND CHEMICAL PROPERTIES
PHYSICAL STATE Off-white crystals, Slight camphor odor
MELTING POINT 137 C
BOILING POINT 344 C
SPECIFIC GRAVITY

1.31

SOLUBILITY IN WATER 0.03 g/100ml
AUTOIGNITION  
pH  
VAPOR PRESSURE 1.1
NFPA RATINGS Health: 1 Flammability: 1 Reactivity: 0
FLASH POINT

 

STABILITY Stable under ordinary conditions

APPLICATIONS
Benzoin is a highly toxic crystalline substance with formula of  C6H5CH(OH)COC6H5, alpha-hydroxy aromatic ketone. It is a white to yellowish crystals; slightly soluble in water, soluble in acetone; melting at 137 C. It is  prepared by the condensation of benzaldehyde in an alkaline cyanide solution. Benzoin and its derivatives are used as intermedaites for the synthesis of organic compounds and as catalysts in photopolymerization. They are used for anticratering in powder coatings.
SALES SPECIFICATION

APPEARANCE

 Light yellow powder

ASSAY

99.5% min

MELTING POINT 134 C min

LOSS ON DRYING

0.5% max

TRANSPORTATION
PACKING 25kgs in Bag
HAZARD CLASS  
UN NO.  
GENERAL DESCRIPTION OF PHOTOINITIATOR
Polymerization is initiated generally by free radical. There are four types of free radical initiators which initiate polymerization.
  • Peroxides including hydroperoxides (tertiary-butyl hydroperoxide, benzoylperoxide)
  • Azocompound thermal initiators (azoisobutyronitrile)
  • Redoxinitiators (mixture of iron(III) acetylacetonate): free radicals are formed by one-electron transferreactions. Useful in low temperature and emulsion polymerization
  • Photoinitiators (benzoin, benzil dimethylketal)

The main advantage of polymerization started by photoinitiators is temperature-independence and easy control. It can be conducted at very low temperatures and can be stopped simply by removing the light source. Photoinitiators are compounds that break down into free radicals upon exposure to ultraviolet radiation. Photoinitiators undergo a unimolecular bond cleavage upon irradiation to yield free radicals (benzoin esters; benzil ketals; alpha-dialkoxy acetophenones; alpha-hydroxy-alkylphenones; alpha-amino alkyl- phosphine; acylphosphine oxides). Another type of photoinitiators undergo a bimolecular reaction where the excited state of the photoinitiator interacts with a second molecule (a coinitiator) to generate free radicals(benzo phenones,amines; thioxanthones,amines; titanocenes). Photoinitiators are widely applied in UV curing inks, wood coatings, paper coatings, optical fiber, PCB, screen printing , paper varnish and other surface coatings.