3 : 4-Epoxy-l-butene

Development of an Industrial Process for the Lewis Acid/Iodide Salt-Catalyzed Rearrcmgement of 3,4-Epoxy-l-Butene to 2,5-Dihydrofuran... 

Epoxy-l-butene (1) is a versatile intermediate for the production of commodity, specialty and fine chemicals (2). An important derivative of 1 is 2,5-dihydrofuran (2,5-DHF). This heterocycle is useful in the production of tetrahydrofuran (3), 2,3-dihydrofuran (4), 1,4-butanediol (5), and many fine chemicals (e.g., 3-formyltetrahydrofuran (6) and cyclopropanes (7)). The homogeneous, Lewis acid and iodide salt-catalyzed rearrangement (isomerization) of 1 to 2,5-DHF has been known since 1976 (8) and is the only practical method for 2,5-DHF synthesis. 

In the development of a 3,4-epoxy-l-butene (1) rearrangement process suitable for industrial scale-up, a number of factors were evident. The product (2,5-DHF) and starting material (1) are both liquids with identical boiling points (66°C). No practical method is known by which to separate these isomers. This fact demands that the catalytic process be performed at high conversion for acceptable economics. The common practice of recycling unreacted starting material was not an option for this process. 

A novel homogeneous process for the catalytic rearrangement of 3,4-epoxy-l-butene to 2,5-dihydrofuran has been successfully developed and scaled-up to production scale. A tri(n-alkyl)tin iodide and tetra-(n-alkyl)phosphonium iodide co-catalyst system was developed which met the many requirements for process operation. The production of a minor, non-volatile side product (oligomer) was the dominating factor in the design of catalysts. Liquid-liquid extraction provided the needed catalyst-oligomer separation process. 

Lahdetie, J. Grawe, J. (1997) Flow cytometric analysis of micronucleus induction in rat bone marrow polychromatic eiythrocytes by l,2 3,4-diepoxybutane. 3.4-epoxy-l-butene, and 1.2-epoxybutane-3,4-diol. Cytometry, 28, 228-235... 

Tretyakova, N., Lin, YP, Sangaiah, R., Upton, PB. Swenberg, J.A. (1997a) Identification and quantitation of DNA adducts from calf thymus DNA exposed to 3,4-epoxy-l-butene. Carcinogenesis, 18, 137-147... 

Dehydration of diols to cyclic ethers. The reagent dehydrates a variety of diols to cyclic ethers with formation of triphenylphosphine oxide as the co-product. Yields of cyclic ethers are high from 1,2-, 1,4- and 1,5-diols. Although (Z)-2-butene-1,4-diol is converted into 2,5-dihydrofuran in 95% yield, the (E)-isomer is converted in 35-40% yield into 3,4-epoxy-l-butene.1... 

We have also determined that the reaction of (Z)-2-butene-l, 4-diol with DTPP in refluxing dichloromethane (CH2CI2) affords 2,5-dihydrofuran (85-87% GLC and 60% isolated yield). On the other hand, treatment of (E)-2-butene-l,4-diol with DTPP in chloroform (61°, 18 h) gave a distilled material (42%) whose 1H NMR spectrum was completely superimposable on an authentic sample of 3,4-epoxy-l-butene (13). This result is in agreement with the ring closure predictions of Baldwin where the "3-exo-trig" cy-clization is predicted to be favored (2). 

When an unsymmetrical secondary alcohol is formed, depending on which carbon-oxygen bond is cleaved. With propylene oxide, for example, a base-catalyzed reaction favors the formation of the secondary alcohol almost exclusively, whereas, a non-catalytic or acid-catalyzed alcoholysis yields a mixture of the isomeric ethers. However, the reactions of other a-epoxides, such as 3,4-epoxy-l-butene, 3,4-epoxy-l-chloropropane (epichlorohydrin), 3,4-epoxy-l-propanol (glycidol), and styrene oxide, are more complicated with respect to which isomer is favored. ... 

In concluding our discussion of the reactions of epoxides, the meth-anolysis of 3,4-epoxy-l-butene might be mentioned. This reaction has been studied in detail, and it illustrates very nicely some of the principles of epoxide reactions which we have considered. In the presence of sulfuric acid the only product isolated was 2-methoxy-3-buten-l-ol (III).27,28 When sodium methoxide was employed as the catalyst, the major product of the reaction was l-methoxy-3-buten-2-ol (IV),28 but some 2-methoxy-3-buten-2-ol was also obtained. 

Epoxides, 115-116, 186, 201, 239 1,2-Epoxybutane, 107 3,4-Epoxy-l-butene, 108 OjJ-Epoxy sulfones, 155 Equilin, 204... 

Materials. VEC was prepared by the catalyzed addition of CO2 to 3,4-epoxy-l-butene using conditions typical of that used industrially [77], then purified by vacuum distillation. Other raw materials were used as received without any additional purification. Mixed xylenes, vinyl acetate (VA), butyl acrylate (BA), butyl methacrylate (BMA), methyl methacrylate (MMA), styrene (St), and t-butyl hydroperoxide were obtained from Aldrich Chemical Company. Lupersol 575 (t-amyl peroxy (2-ethylhexanoate)) was supplied by Elf Atochem. Vazo 67 (2,2 -azobis(2-methylbutyronitrile)) was obtained from DuPont Chemical Company. Vinyl pivalate (NE05), vinyl 2-ethylhexanoate (V2EH), Tergitol NP-40 (non-ionic surfactant) and QP-300 (hydroxy ethyl cellulose) were obtained from Union Carbide Coq)oration. Aerosol OT-75 (surfactant) was obtained from Cytec. Sodium formaldehyde sulfoxylate was obtained from Henkel Corporation. Ethyl 3-ethoxy propionate (EEP), propylene glycol monomethyl ether (PM) and PM acetate (PM Ac) are Eastman Chemical Company products. 

Alkali metal iodide 3,4-epoxy- l-butene Fatty acids 130)... 

The ortho-ester functionalized polymers can be hydrolyzed to the corresponding carboxyl functionalized polymers. Similarly, fimctionalization with the oxiranes, glycidylpropyltrimethoxysilane, 3,4-epoxy-l-butene, and 1,1,1-trifluoro-2,3-epoxypropane has been investigated (195) to prepare trimethoxysilyl functionalized polymers, 1,3-diene fiinctionalized macromonomers, and trifluoromethyl functionalized polsrmers, respectively. Secondary amine functionalized polymers were prepared by termination with iV-(benzylidene)methylamine and also using an iV-benzyl tertiary amine functionalized alkyl lithimn initiator followed by hy-drogenolysis of the benzyl group. 

Oxirane compounds such as 3,4-epoxy-l-butene [49], (2,3-epoxy-l-propanol) glycidol [50], and 2,3-epoxybutanoic acid [51] can be used to... 

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