Monopropylene glycol

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

Table 2 shows the production, sales, and value for the glycols in the United States in 1990. Production of monopropylene glycol peaked in 1988 at 404,000 t. Imports have been minimal except for the mid-1980s when 25,600 t were imported in 1984. In the period 1986—1989 U.S. exports averaged about 75,000 t per year. 

In fat-free recipes where this method caimot be practiced, it is possible to add and mix vanillin powder with eggs. An alternative to vanillin powder for highly mechanized processes is to use a vanillin solution or Hquid flavor the solvent used is either ethanol- or monopropylene glycol-based. 

Vanillin is used in flavored milk, desserts, yogurts, sorbets, and ice cream. Generally, vanillin is used in Hquid form either in ethanol solution with a vanillin concentration up to 400 g/L or in monopropylene glycol with a vanillin concentration to 300 g/L. Both concentrations are given for a temperature of 20°C to avoid recrystaUization problems. 

Because manufacturers are unwilling to generate data to substantiate the acceptability of continued use, the other tin compounds of the case have become obsolete, including bis (tributyltin) adxpate[7437-35-6]y bis(tributyltin) sulfosalicylate/44/5M 2-/]y tributyltin acetate [56-36-0], tributyltin acrylate[13331-52-7], tributyltin chloride[1461 -22-9]y tributyltin linoleate/24124-25-2], tributyltin monopropylene glycol maleate[53466-85-6]y and tributyltin neodecanoate[28801 -69-6]. Because of the substantial number of tin compounds, this is not a typical example, but it does illustrate the point that there has been a large decline in the availability of niche products. 

Using water, the heat transfer coefficient on the 50-cm-diameter disc regularly exhibited a minimum value at a radius of about 17 cm. On the other hand, with the use of a water/60% monopropylene glycol mixture, no minimum was observed and the absolute performance was much poorer than that obtained with water. This behavior is attributed to the tangential fluid slip generated as the feed liquid is brought up to the rotor s angular velocity. This slip appears to be more marked with low-viscosity liquids, which seems intuitively reasonable. 

Synonyms 1,2-Propanediol a-Propylene glycol Methyl glycol Methylethyl glycol Methylethyl-ene glycol Monopropylene glycol PG 12 Sirlene ... 

MONOPROPYLENE GLYCOL (57-55-6) Combustible liquid (flash point 210°F/ 99°C oc). Violent reaction with strong oxidizers, alkalis. Incompatible with sulfuric acid, nitric acid, caustic materials, aliphatic amines, isocyanates, boranes. 

Chem. Descrip. Unsaturated polyamide, acid ester salts in solvents (xylene,n-butanol, monopropylene glycol)... 

Chem. Descrip. Monopropylene glycol monomethyl ether CAS 107-98-2 EINECS/ELINCS 203-539-1 Uses Solvent for brake fluids, hard-surf, cleaners, leather dyeing, paints, coatings, printing inks, textile vat dyeing and printing, adhesives, antifreeze, floor waxes/polishes, insect repellents solubilizer for dyes plasticizer... 

Monopropylene glycol. See Propylene glycol Monopropylene glycol methyl ether. See Methoxyisopropanol... 

Synonyms 1,2-propanediol 1,2-dihydroxypropane methylethylene glycol trimethyl glycol 1,2-propylene glycol monopropylene glycol propane-i,2-diol a-propyleneglycol Dowfrost PG 12 Sirlene Solar Winter Ban propanediol... 

In the chlorohydrination step, the reactants propylene and hypochlorous acid (chlorine and water) are converted into two propylene chlorohydrin isomers (90% l-chloro-2-propanol and 10% 2-chloro-l-propanol). Yields of up to 94% can be achieved in modern commercial plants. The main by-products formed in this reaction step are dichloropropane (3-10%), dichloropropanol (0.3-1.2%), and dichlorodiisopropyl ether (0.2-1.7%). In the second step (dehydrochlorination, also called epoxidation or saponification ) the aqueous propylene chlorohydrin solution is treated with slaked lime or caustic soda. Propylene oxide and calcium or sodium chloride are formed. In a commercial process 1.4-1.5 units of chlorine are consumed to produce one unit of propylene oxide. Typical by-products are monopropylene glycol, epichlorohydrin, glycerol monochlorohydrin, glycerol, propanal, and acetone. In dehydrochlorination, propylene oxide yields of up to 96% can be obtained. 

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