Propylene Glycol Assignment Example | Topics and Well Written Essays - 2000 words

Propylene Glycol - Assignment Example PG is also known under the name 1,2-propylene glycol, 1,2-dihydroxypropane, 1,2-propanediol, ethylene glycol, and methyl glycol. The proper IUPAC chemical name is propane-1,2-diol. Its CAS Registry Number on the U.S. EPA Toxic Substances Control Act (TSCA) inventory of chemical substances is [57-55-6]. Common commercial names of this substance are Propylene Glycol Industrial (PGI) and Propylene Glycol USP (PG USP) (Martin and Murphy, 2006). The physical properties of propylene glycol are presented in Table 1. All of the glycols are very miscible with water, ethanol, acetone, and chloroform. Propylene glycol is also a hygroscopic compound (Martin and Murphy, 2006). The structural formula of propylene glycol is given in figure 1. Its structural isomer with the same formula is 1,3-propanediol. PG has also two enantiomers: one is (R)-1,2-propanediol and the other is (S)-1,2-propanediol. This compound has two functional hydroxyl group: primary and secondary that distinguish it from the ethylene glycol (McKetta, 1993). Chemical properties of propylene glycol are typical for this group of compounds. It undergoes the reactions with carboxylic acids, and their derivatives (halides and anhydrides) forming esters; reaction with hydroxides of alkali metals forming salts, and interaction with aldehydes and ketones where the products are acetals and ketals. The reaction with acids is important for obtaining polyesters. The next important commercial product is polyether obtained by dehydration of propylene glycol. Reactions with aldehydes and ketones are used for protection of aldehyde or ketone functionality in organic synthesis (Martin and Murphy, 2006). Propylene glycol is used in organic synthesis, synthesis of polymers, medicine, and cosmetics. Its mixture of water has the low freezing point and, thus, this compound is used as antifreeze.