Epoxides glycidyl ethers

Hemminki, K., Falck, K. Vainio. H. (1980) Comparison of alkylation rates and mutagenicity of directly acting industrial and laboratory chemicals. Epoxides, glycidyl ethers, methylating and ethylating agents, halogenated hydrocarbons, hydrazine derivatives, aldehydes, thiuram and dithiocarbamate derivatives. Arch. Toxicol., 46, 277-285... 

In 1957, it was discovered that organometaUic catalysts gave high mol wt polymers from epoxides (3). The commercially important, largely amorphous polyether elastomers developed as a result of this early work are polyepichlorohydrin (ECH) (4,5), ECH—ethylene oxide (EO) copolymer (6), ECH—aUyl glycidyl ether (AGE) copolymer (7,8), ECH—EO—AGE terpolymer (8), ECH—propylene oxide (PO)—AGE terpolymer (8,9), and PO—AGE copolymer (10,11). The American Society for Testing and Materials (ASTM) has designated these polymers as follows ... 

Crystallinity is low the pendent allyl group contributes to the amorphous state of these polymers. Propylene oxide homopolymer itself has not been developed commercially because it cannot be cross-baked by current methods (18). The copolymerization of PO with unsaturated epoxide monomers gives vulcanizable products (19,20). In ECH—PO—AGE, poly(ptopylene oxide- o-epichlorohydrin- o-abyl glycidyl ether) [25213-15-4] (5), and PO—AGE, poly(propylene oxide-i o-abyl glycidyl ether) [25104-27-2] (6), the molar composition of PO ranges from approximately 65 to 90%. 

The epoxidation is generally conducted in two steps (/) the polyol is added to epichlorohydrin in the presence of a Lewis acid catalyst (stannic chloride, boron triduoride) to produce the chlorohydrin intermediate, and (2) the intermediate is dehydrohalogenated with sodium hydroxide to yield the aliphatic glycidyl ether. A prominent side-reaction is the conversion of aliphatic hydroxyl groups (formed by the initial reaction) into chloromethyl groups by epichlorohydrin. The aliphatic glycidyl ether resins are used as flexibilizers for aromatic resins and as reactive diluents to reduce viscosities in resin systems. 

The epoxide resins of the glycidyl ether type are usually characterised by six parameters ... 

Although the first and still most important epoxide resins are of the glycidyl ether type, other epoxide resins have been commercially marketed in recent years. These materials are generally prepared by epoxidising unsaturated compounds using hydrogen peroxide or peracetic acid. 

As with the other non-glycidyl ether resins the absence of the ether oxygen near to the epoxide group results in low reactivity with amine hardemers whereas activity with acid anhydride proceeds at reasonable rates. 

Non-glycidyl ether epoxides Diluents, Rexibilisers tmd other Additives Structure and Properties of Cured Resins Applications... 

The preferred catalysts are salts of inorganic and organic acids as well as tertiary amines. Phthalic anhydride, succinic anhydride and maleic anhydride are typical acid anhydrides, while ethylene oxide, propylene oxide, epichlorohydrin and phenyl glycidyl ether are typical epoxides. The synthesis of a ladder polymer was carried out by using bisanhydrides264. ... 

In another study that appeared prior to the advent of CASTing, the traditional combination of epPCR and DNA shuffling was used to enhance the enantioselectivity of the hydrolytic kinetic resolution of p-nitro phenyl glycidyl ether and other epoxides catalyzed by the EH from Agrobacterium radiobacter [59]. Several mutants were obtained with up to 13-fold improved enantioselectivity. The amino acid exchanges took place around the active site. 

An inhibitor during drilling and servicing of oil and gas wells is a condensate of aminopyrazine and an epoxide compound, such as the glycidyl ether of a mixture of Cn to C14 alkanols [604]. 

However, disappointingly low selectivity was observed with monosubstituted aliphatic epoxides such as 1-epoxyoctane (la, E<5) or benzyl glycidyl ether (le, <2) [51,55]. On the other hand, sterically more demanding 2,2-disubsti-tuted oxiranes (2) turned out to be much better substrates (Scheme 9, Table 2). 

Perez, H.L. and Osterman-Golkar, S. Biotransformation of the double bond in allyl glycidyl ether to epoxide ring. Evidence from hemoglobin adducts in mice, Chem. Biol. Interact., 125(l) 17-28, 2000. 

Vinyl epoxides represent another class of compounds known to participate in CM reactions mediated by ruthenium NHG catalysts. The reactivity of these catalysts is unique, as catalyst 2 is typically limited to allyl glycidyl ether ... 

Hemminki, K., Paasivirta, J., Kurkirinne, T. Virkki, L. (1980) Alkylation products of DNA bases by simple epoxides. Chem.-biol. Interact., 30, 259-270 Hine, C.H., Kodama, J.K., Wellington, J.S., Dunlap, M.K. Anderson H.H. (1956) The toxicology of glycidol and some glycidyl ethers. Arch. ind. Health, 14, 250-264 Hooper, K., LaDou, J., Rosenbaum, J.S. Book, S.A. (1992) Regulation of priority carcinogens and reproductive or developmental toxicants. Am. J. ind. Med., 22, 793-808 Hussain, S. (1984) Dose-response relationships for mutations induced in E. coli by some model compounds. Hereditas, 101, 57-68... 

PDPGE = 3-n-pentadecenyl phenyl glycidyl ether C,6 a-OE = C,6 alpha olefin epoxide... 

The increase in alkylation efficiency of HEC with quaternary ammonium hydroxide is not limited to DPGE. Experiments were conducted in which HEC was alkylated with 1-bromohexadecane (cetyl bromide), 3-n-pentadecenyl phenyl glycidyl ether (PDPGE)14, or 1,2-epoxyhexadecane (C]6 a-olefin epoxide) in the presence of either sodium hydroxide or benzyltrimethylammonium hydroxide. As before, the molar A/HEC ratio was 0.50, and the water content of the diluent in the benzyltrimethylammonium hydroxide experiment was decreased to compensate for the higher water content of the base so that the final water content of both reactions was the same (14.4%). The hexadecyl content of the polymers was measured by gas chromatography. The sodium hydroxide mediated reaction of 1-bromohexadecane yielded a hexadecyl alkylation efficiency of 0.5%, while the benzyltrimethylammonium hydroxide reaction yielded a hexadecyl alkylation efficiency of 6.2%. A twelve-fold increase in the hexadecyl alkylation efficiency was observed in the reaction conducted with the quaternary ammonium hydroxide. 

These compounds can initiate anionic polymerisation of epoxides, and when R, = H the secondary amine can react by addition to an epoxide group. Farkas and Strohm 64> have studied the reaction of 2-ethyl-4-methyl imidazole with phenyl glycidyl ether and BADGE resin using chemical analysis and proton NMR spectroscopy. They found that the imidazole readily forms adducts with epoxide of 1 1 and 1 2 molecular ratio ... 

More recently Bradley and co-workers288 demonstrated a fourth significant product in this reaction to be l,3-dichloro-2-propanol. formed by addition of hydrochloric acid to epiehlorohydrin. These authors then showed that under suitable conditions phenyl glycidyl ether can be mode to react wjth a chlorohydrin. There are formed in this manner a new epoxide and l-chloro-D-phenoxy-2-propanol, ah... 

Bradley and co-workers 8 advanced the attractive prenuae that certain difficultly accessible epoxides might be synthesised oonveu nil> by this approach, provided that the glycidyl ether need is a good hydrogen chloride acceptor and that the desired products can removed readily from the equilibrium mixture. 

The early literature of epoxide chemistry contains several accounts of the reaction of hydrogen cyanide with epichlorohydrin, 11-1T1 epibromohydrin,10 ethyl glycidyl ether,J- and related substance Attack by the nucleophilic aperies, CN- ion in this case, occurs uniquely at the site furthest from the polar atom,. e. at the terminal epoxidi-carbon atom (Eq. 787), An important contribution was made by... 

Glycidyl ethers (Eq. 67 ) behave as do other terminal epoxides on treatment with diethyl sodiomalonate. ethyl Bodioacetoaoetate, ami ethyl sodiocyanoaoetate.1488 1,81 Glycidamines (Eq. 878) act in the same manner in the presence of diethyl sodiomalonate, 487 as due also ),2 3,4 diepoxybutanem (Eq. 879. ... 

The use of model compounds is a convenient starting point to determine the reaction path, particularly for stepwise polymerizations. For epoxy-amine systems, a monofunctional epoxide such as phenyl glycidyl ether (PGE) is often used for these studies (Verchere et al., 1990 Mijovic and Wijaya, 1994). Figure 5.10 shows the reaction scheme for the curing of a monoepoxide with a diamine. 

The reaction of epoxide resins with dicyanates was investigated using a model system. The system consisted of phenyl glycidyl ether and cumylphenyl cyanate [67]. Three reactions proceeded in the system ... 

Other products that may be epoxidized in this way include dihydric and trihydric phenols, aliphatic polyols such as glycerol, and simple alcohols such as butanol or alyl alcohol. These products, especially the monofunctional glycidyl ethers, are used at relatively low percentages to reduce the viscosity of formulations containing DGEBA resins. In this way, they act as reactive diluents. 

---