Tripropylene

The propylene glycol family of chemical compounds consists of monopropylene glycol (PG), dipropylene glycol (DPG), and tripropylene glycol (TPG). 

Polyethers are also products of commercial importance. Ethers can be formed by thermal dehydration, as shown for the formation of dipropylene glycol from propylene glycol. CycHc ethers can form by elimination of water from di- or tripropylene glycol. 

Propylene glycol, dipropylene glycol, and tripropylene glycol all have several isomeric forms. Propylene glycol has one asymmetric carbon and thus there are two enantiomers (R)-I,2-propanediol and (3)-1,2-propanediol. 1,3-Propanediol is a stmctural isomer. Dipropylene glycol exists in three stmctural forms and since each stmctural isomer has two asymmetric carbons there are four possible stereochemical isomers per stmcture or a total of twelve isomers. These twelve consist of four enantiomer pairs and two meso- compounds. Tripropylene glycol has four stmctural isomers and each stmctural isomer has... 

Physical properties Prop ene glycol Dip ropylene glycol Tripropylene glycol... 

Rats showed no adverse effects from 5.0% dipropylene glycol in their drinking water for 77 days, but at a dose of 10.0% in the drinking water, kidney and Hver injury and some deaths occurred (35). A sufficient number of studies have not been carried out on tripropylene glycol to permit conclusions to be drawn regarding its chronic oral toxicity. 

Dipropylene glycol is produced in the manufacture of propylene glycol and finds utiUty as an indirect food additive, in brake-fluid formulations, cutting oils, soaps, and solvents. Tripropylene glycol also finds use as a solvent, as textile soaps, and as lubricants (273). 

Glycol Ethers. Glycol ethers are produced by reaction of propylene oxide with various alcohols such as methanol, ethanol, butanol, and phenol. The products are the mono-, di-, and tripropylene glycol ethers. These products are used in protective coatings, inks, textile dyeing, cleaners, antiicing additives for jet fuel, and as chemical intermediates (276). 

Chemical Designations - Synonyms Nonene (non-linear) Propylene trimer Tripropylene Chemical Formula CjHij. 

Tetrapropylene is manufactured from propylene (containing 50% propane) with the use of a phosphoric acid catalyst at 70-bar pressure and 200°C. Under these conditions a product mixture is obtained which has to be purified by distillation. Unconverted propane is obtained as the first fraction, followed by tripropylene which can either be sent back to the polymerization or used as motor fuel. The third fraction consists of the desired tetrapropylene. 

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