Cyclic alkylene carbonate

The cyclic alkylene carbonates have also been applied as the cure-accelerators of phenol-formaldehyde (PF) [262-266] and sodium silicate [267] resin systems, which are widely used in foundry sand and wood binder applications. 

The first reports describing the formation of cyclic carbonates (CCs) appeared during the early 1930s [99, 100], whilst the first patents (essentially related to the synthesis of ethene and propene carbonates) appeared more than 50 years ago [101, 102]. The Huntsman Corporation is one the world s largest producers of alkylene carbonates, with a capacity of 33 kt per year, covering approximately 50% of CC production worldwide. Today, CCs are widely used in the manufacture of... 

The transesterification of 1,2-diols by reaction with carbonates, both cyclic and linear, produces five-membered alkylene carbonates almost exclusively. A well-known example of this is the reaction of DMC with propene glycol to yield PC [295],... 

The coordination polymerisation of cyclic esters concerns mostly lactones, especially those containing a four-membered ring in the molecule. There is, however, an interest in the coordination polymerisation of such oxacyclic ester monomers as lactide and alkylene carbonate and, to a lesser extent, in the... 

Copolymerisation of propylene oxide as well as other oxiranes with carbon dioxide in the presence of zinc-based coordination catalysts is generally accompanied with the formation of a cyclic five-membered carbonate, propylene carbonate or another alkylene carbonate [147,206,207,210,212,230]. The alky-lene carbonate, however, is not the precursor for poly(alkylene carbonate), since it hardly undergoes a polymerisation under the given conditions [142-146],... 

Another carbon dioxide insertion reaction is observed with Al (TPP)(OMe) This compound readily and reversibly traps carbon dioxide at room temperature in the presence of 1-methylimidazole. The trapped carbon dioxide is sufficiently activated to react with an epoxide at room temperature, thus producing the corresponding alkylcarbonate. As illustrated in Scheme 11, the cyclic carbonate is considered to be formed - at least partly - by nucleophilic attack on a linear intermediate. Thus the alkoxide aluminum porphyrin-methylimidazole system would be a good catalyst for synthesis of alkylene carbonates from carbon dioxide and epoxides under mild conditions. 

The alkylene carbonates are easily available through transesterification of dialkyl carbonates (usually dimethyl or diethyl carbonate) or diphenyl carbonate with appropriate 1,2-diols in the presence of alkaline catalysts.This approach for the preparation of five-membered cyclic carbonates also was described in the 1950s by Ludwig and Piech ° and Sarel et al ... 

Vinyl-functional alkylene carbonates, useful in the preparation of polymers that contain alkylene carbonate pendant groups, can also be prepared from GC. Two examples are the reaction of GC with maleic anhydride and acryloyl chloride to produce the acrylate-functional cyclic carbonates (3 and 4, respectively. Scheme 24). Although the transesterification of alkyl esters such as dimethyl maleate or methyl acrylate by reaction with GC represents an obvious means of obtaining the above materials, the temperatures required of such processes (>100°C) result in unwanted polymerization of both the reactant and product species, even in the presence of well-known radical inhibitors such as 2,6-di-tert-butyl-p-cresol or phenothiazine. In addition, the synthesis of vinyl-functional alkylene carbonates is greatly complicated by the fact that such materials cannot be purified by distillation and must be stored at temperatures < 0 ° C in the presence of a... 

Vinyl-functional alkylene carbonates can also be prepared from the corresponding epoxides in a manner similar to the commercial manufacture of ethylene and PCs via CO2 insertion. The most notable examples of this technology are the syntheses of 4-vinyl-1,3-dioxolan-2-one (vinyl ethylene carbonate, VEC) (5, Scheme 24) from 3,4-epoxy-1-butene or 4-phenyl-5-vinyl-l,3-dioxolan-2-one (6, Scheme 24) from analogous aromatic derivative l-phenyl-2-vinyl oxirane. Although the homopolymerization of both vinyl monomers produced polymers in relatively low yield, copolymerizations effectively provided cyclic carbonate-containing copolymers. It was found that VEC can be copolymerized with readily available vinyl monomers, such as styrene, alkyl acrylates and methacrylates, and vinyl esters.With the exception of styrene, the authors found that VEC will undergo free-radical solution or emulsion copolymerization to produce polymeric species with a pendant five-membered alkylene carbonate functionality that can be further cross-linked by reaction with amines. Polymerizations of 4-phenyl-5-vinyl-l,3-dioxolan-2-one also provided cyclic carbonate-containing copolymers. 

These polymers, with number average molecular weights of about 50,000, have decomposition temperatures of 220-250°C and good to excellent tensile properties. The poly(alkylene carbonates) decompose and bum cleanly to yield mainly the appropriate cyclic carbonate with minimal ash residue and only trace levels of contaminants. Because of these clean burning characteristics, suggested applications include use as a ceramic binder metal-casting material. 

The only practical method for preparing alkylene thioureas is by the action of the diamines upon carbon disulfide in aqueous alcohol. The final heating is essential to convert the thio-carbamic acid into the cyclic compound, the addition of hydrochloric acid being beneficial. ... 

Cyclic carbonates of glycols—e.g., ethylene carbonate or propylene carbonate—are readily prepared from carbon dioxide and the alkylene oxide (135). 

Cyclic sulfates reacted with LiPPh2 to form a series of new amphiphilic or water-soluble ligands monotertiary phosphines with one or two alkylene sulfate chains 409 and ditertiary phosphines with one or two hydrophilic tails attached to bridgehead carbon atom 410. The coordination to Rh complexes afforded water-soluble... 

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