Resins epichlorohydrin-based

Key Words Ethylene oxide, Propylene oxide. Epoxybutene, Market, Isoamylene oxide. Cyclohexene oxide. Styrene oxide, Norbornene oxide. Epichlorohydrin, Epoxy resins, Carbamazepine, Terpenes, Limonene, a-Pinene, Fatty acid epoxides, Allyl epoxides, Sharpless epoxidation. Turnover frequency, Space time yield. Hydrogen peroxide, Polyoxometallates, Phase-transfer reagents, Methyltrioxorhenium (MTO), Fluorinated acetone, Alkylmetaborate esters. Alumina, Iminium salts, Porphyrins, Jacobsen-Katsuki oxidation, Salen, Peroxoacetic acid, P450 BM-3, Escherichia coli, lodosylbenzene, Oxometallacycle, DFT, Lewis acid mechanism, Metalladioxolane, Mimoun complex, Sheldon complex, Michaelis-Menten, Schiff bases. Redox mechanism. Oxygen-rebound mechanism, Spiro structure. 2008 Elsevier B.V. 

The base resin used in the formulations of this study was Epocryl-12, made by Shell Chemical Company. It is typical of the vinyl ester resins produced by the reaction of an acrylic monomer with a bisphenol-A/epichlorohydrin... 

Epoxy novolac resins are produced by reacting a novolac resin with epichlorohydrin to obtain epoxy functionality. Unlike the Bisphenol A based resins, the epoxy novolac resins have an... 

Figure 5.1 Typical epoxy resin and hardening reaction using a primary diamine hardener, (a) A bisphenol A-epichlorohydrin based epoxy resin. The most important type is when n 0.2 and the liquid resin is essentially (b) a simple diglycidyl ether of bisphenol A (DGEBA). (c) A primary diamine hardener, (d) a crosslinked, thermosetting epoxy adhesive.

S.-P. Zou, E.-H. Du,Z.-C. Hu, Y.-G. Zheng, Enhanced biotransformation of l,3-dichloro-2-pro-panol to epichlorohydrin via resin-based in situ product removal process, Biotechnol. Lett. 35 (2013) 937-942. 

The majority of 2-methylphenol is used in the production of novolak phenoHc resins. High purity novolaks based on 2-methylphenol are used in photoresist appHcations (37). Novolaks based on 2-methylphenol are also epoxidized with epichlorohydrin, yielding epoxy resins after dehydrohalogenation, which are used as encapsulating resins in the electronics industry. Other uses of 2-methylphenol include its conversion to a dinitro compound, 4,6-dinitro-2-methylphenol [534-52-1] (DNOC), which is used as a herbicide (38). DNOC is also used to a limited extent as a polymerization inhibitor in the production of styrene, but this use is expected to decline because of concerns about the toxicity of the dinitro derivative. 

Specialty Epoxy Resins. In addition to bisphenol, other polyols such as aUphatic glycols and novolaks are used to produce specialty resins. Epoxy resins may also include compounds based on aUphatic, cycloaUphatic, aromatic, and heterocycHc backbones. Glycidylation of active hydrogen-containing stmctures with epichlorohydrin and epoxidation of olefins with peracetic acid remain the important commercial procedures for introducing the oxirane group into various precursors of epoxy resins. 

Liquid epoxy resin based on the reaction product of epichlorohydrin and bisphenol A or bisphenol F mild to moderate irritants mild to moderate sensitizers low volatility, exposure unlikely unless heated, sprayed, or spread over large unventilated surface low toxicity... 

This reaction is quite general and, since the organic group R can be aliphatic, cycloaliphatic, or aromatic, there is wide scope for variation in the composition of epoxy resins. In practice, however, the most frequently used materials are those based on bisphenol A and epichlorohydrin, which represent over 80% of commercial resins. 

Virtually all epoxy resins are made with starting materials based on epichlorohydrin, principally by reaction with bisphenol A. It is also used for the preparation of resins to increase the wet strength of paper. Both epichlorohydrin and glycidol are used in the manufacture of pharmaceuticals. 

Synthesis Epoxy resins consisting ofglycidyl ether, ester and amines are generally prepared by the condensation reaction between diol, dibasic acid or amine and epichlorohydrin in the presence of sodium hydroxide with the elimination of hydrochloric acid. The commercially available epoxy resins are, however, made by the reaction of epichlorohydrin and bisphenol-A. Cashew nut shell liquid (CNSL)-based novolac epoxy resins have also been reported [342]. 

Epichlorohydrin is a major raw material for epoxy and phenoxy resins, and is used in the manufacture of glycerine, in curing propylene-based rubbers, as a solvent for cellulose esters and ethers, and in resins with high wet-strength for the paper industry (Lewis, 1993). 

According to the 1990-93 CAREX database for 15 countries of the European Union (Kauppinen etal., 1998) and the 1981-83 National Occupational Exposure Survey (NOES) in the United States (NOES, 1997), approximately 25 000 workers in Europe and as many as 80 000 workers in the United States were potentially exposed to epichlorohydrin (see General Remarks). Occupational exposures to epichlorohydrin may occur in its use as a solvent and in resin production and use, the manufacture of glycerine and use of propylene-based nibbers. 

Nested case-control studies for lung (Barbone et al., 1992) and central nervous system (Barbone et al., 1994) neoplasms w ere conducted using the full cohort of dye and resin manufacturing workers reported on by Delzell et al. (1989). Exposure w as assessed on an ordinal scale based on job titles, w ork areas, and potential for contact. When the work histories of 51 lung cancer cases were compared with those of 102 controls matched for year of birth, an association was observed with potential epichlorohydrin... 

Exposure to epichlorohydrin may occur during the production and use of resins, glycerine and propylene-based rubbers and its use as a solvent. It has been detected at low levels in water. 

---