Carbonates propylene

Carbonic acid, cyclic propylene ester cyclic methylethylene carbonate cyclic propylene carbonate 4-methyl-2-oxo-l,3-dioxolane 1,2-propanediol cyclic carbonate 1,2-propylene carbonate. 

Propylene carbonate is a clear, colorless, mobile liquid, with a faint odor. 

Propylene carbonate is used mainly as a solvent in oral and topical pharmaceutical formulations. 

In topical applications, propylene carbonate has been used in combination with propylene glycol as a solvent for corticosteroids. The corticosteroid is dissolved in the solvent mixture to vield microdroplets that can then be dispersed in petrolatum. Propylene carbonate has been used as a dispensing solvent in topical preparations.  

Propylene carbonate may additionally be used as a solvent, at room and elevated temperatures, for many cellulose-based polymers and plasticizers. Propylene carbonate is also used in cosmetics. 

Common contaminants in commercial PC include propylene oxide, carbon dioxide, propanediols, allyl alcohol, ethylene carbonate, and water. Purification may be accomplished by percolation through 5 A molecular sieves (activated by treatment at 350 °C for 14 h under argon), followed by distillation under vacuum and storage under molecular sieves. 

Water Less than 0.04% by Karl Fischer titration 

Primary and secondary amines by ninhydrin test Less than 10 ppm 

Peroxides Less than two mg/1 as H2O2 at time of packaging 

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Fig. V-5. The repulsive force between crossed cylinders of radius R (1 cm) covered with mica and immersed in propylene carbonate solutions of tetraethylammonium bromide at the indicated concentrations. The dotted lines are from double-layer theory (From Ref. 51).

The location and shape of the entire electrocapillary curve are affected if the general nature of the medium is changed. Fawcett and co-workers (see Ref. 126) have used nonaqueous media such as methanol, V-methylformamide, and propylene carbonate. In earlier studies, electrocapillaiy curves were obtained for O.OIA/ hydrochloric acid in mixed water-ethanol media of various compositions [117, 118]. The surface adsorption of methanol, obtained from... 

An interesting material with both electro- and therm ochromism behavior, Li VO2 was evaluated for a "smart window" appHcation (25). Films of Li V02 were prepared by reactive sputtering and annealing an electrolyte of LiClO and propylene carbonate. 

CycHc carbonates are made by treating 1,2-diols with dialkyl carbonates using an alkyl ammonium and tertiary amine catalyst. The combination of propylene glycol and dimethyl carbonate has been reported to result in a 98% yield of propylene carbonate (21). 

The physical properties of finish removers vary considerably due to the diverse uses and requirements of the removers. Finish removers can be grouped by the principal ingredient of the formula, method of appHcation, method of removal, chemical base, viscosity, or hazardous classification. Except for method of apphcation, a paint remover formulation usually has one aspect of each group, by which it can be used for one or more appHcations. A Hst of the most common organic solvents used in finish removers has been compiled (3). Many are mentioned throughout this article others include ethyl lactate [97-64-3] propylene carbonate [108-32-7] furfural alcohol [98-01-1/, dimethyl formamide [68-12-2] tetrahydrofuran [109-99-9] methyl amyl ketone [110-43-0] dipropylene glycol methyl ether [34590-94-8] and Exxate 600, a trade name of Exxon Chemicals. 

Mono- and dialkanolamines react readily with ethylene or propylene carbonates to yield carbamates. 

Carbon Dioxide and Carbon DisulUde. Propylene oxide and carbon dioxide react ia the presence of tertiary amine, quaternary ammonium haUdes, or calcium or magnesium haUde catalysts to produce propylene carbonate (52). Use of catalysts derived from diethyUiac results ia polycarbonates (53). 

Much analytical study has been required to estabHsh the materials for use as solvents and solutes in lithium batteries. References 26 and 27 may be consulted for discussions of electrolytes. Among the best organic solvents are cycHc esters, such as propylene carbonate [108-32-7] (PC), C H O, ethylene carbonate [96-49-1] (EC), C H O, and butyrolactone [96-48-0] and ethers, such as dimethoxyethane [110-71-4] (DME), C H q02, the glymes,... 

Formation of Cyclic Carbonates. In the absence of water, chlorohydrins such as 2-chloroethanol and l-chloro-2-propanol react with an alkah carbonate or bicarbonate to produce cycHc carbonates such as ethylene carbonate [96-49-1] and propylene carbonate [108-32-7] ia yields of up to 80%... 

Physical solvent type Fluor solvents (propylene carbonate example), Selexol Physical/chemical type Sulfinol Carbonate type Potassium carbonate Solution batch type Lo-Cat, Chemsweet Bed batch type Iron Sponge, Mol Sieve... 

The Fluor solvent, propylene carbonate, is used primarily for removal of COi from high pressure gas... 

The mechanism of this reaction has been studied by several groups [133,174-177]. The consensus is that interaction of ester with the phenolic resole leads to a quinone methide at relatively low temperature. The quinone methide then reacts rapidly leading to cure. Scheme 11 shows the mechanism that we believe is operative. This mechanism is also supported by the work of Lemon, Murray, and Conner. It is challenged by Pizzi et al. Murray has made the most complete study available in the literature [133]. Ester accelerators include cyclic esters (such as y-butyrolactone and propylene carbonate), aliphatic esters (especially methyl formate and triacetin), aromatic esters (phthalates) and phenolic-resin esters [178]. Carbamates give analogous results but may raise toxicity concerns not usually seen with esters. 

This process uses propylene carbonate as a physical solvent to remove CO2 and H2S. Propylene carbonate also removes C2+ hydrocarbons, COS, SO2, CS2, and H2O from the natural gas stream. Thus, in one step the natural gas can be sweetened and dehydrated to pipeline quality. In general, this process is used for bulk removal of CO2 and is not used to treat to less than 3% CO2, as may be required for pipeline quality gas. The system requires special design features, larger absorbers, and higher circulation rates to obtain pipeline quality and usually is not economically applicable for these outlet requirements. 

Propylene carbonate has the following characteristics, which make k suitable as a solvent for acid gas treating ... 

The importance of the solvent, in many cases an excess of the quatemizing reagent, in the formation of heterocyclic salts was recognized early. The function of dielectric constants and other more detailed influences on quatemization are dealt with in Section VI, but a consideration of the subject from a preparative standpoint is presented here. Methanol and ethanol are used frequently as solvents, and acetone,chloroform, acetonitrile, nitrobenzene, and dimethyl-formamide have been used successfully. The last two solvents were among those considered by Coleman and Fuoss in their search for a suitable solvent for kinetic experiments both solvents gave rise to side reactions when used for the reaction of pyridine with i-butyl bromide. Their observation with nitrobenzene is unexpected, and no other workers have reported difficulties. However, tetramethylene sulfone, 2,4-dimethylsulfolane, ethylene and propylene carbonates, and salicylaldehyde were satisfactory, giving relatively rapid reactions and clean products. Ethylene dichloride, used quite frequently for Friedel-Crafts reactions, would be expected to be a useful solvent but has only recently been used for quatemization reactions. ... 

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