1.3- Butadiene, oxidation

Another butadiene oxidation process to produce butanediol is based on the 1,4-addition of /-butyl hydroperoxide to butadiene (108). Cobalt on siHca catalyzes the first step. This is followed by hydrogenation of the resulting olefinic diperoxide to produce butanediol and /-butyl alcohol. 

A wide variety of new approaches to the problem of product separation in homogeneous catalysis has been discussed in the preceding chapters. Few of the new approaches has so far been commercialised, with the exceptions of a the use of aqueous biphasic systems for propene hydroformylation (Chapter 5) and the use of a phosphonium based ionic liquid for the Lewis acid catalysed isomerisation of butadiene monoxide to dihydrofuran (see Equation 9.1). This process has been operated by Eastman for the last 8 years without any loss or replenishment of ionic liquid [1], It has the advantage that the product is sufficiently volatile to be distilled from the reactor at the reaction temperature so the process can be run continuously with built in product catalyst separation. Production of lower volatility products by such a process would be more problematic. A side reaction leads to the conversion of butadiene oxide to high molecular weight oligomers. The ionic liquid has been designed to facilitate their separation from the catalyst (see Section 9.7)... 

Figure 3. Butadiene oxidation on HY, and VoOc and/or PoOc loaded HY V-P-V2O5-P2O5 (derived from [40-41]).

Butadiene oxidation to furan was also performed on ZSM zeolites prepared in the presence of v3+ [42-44]. Non-oxidative activation prevents collapse of the zeolite structure to cristoballite and improves both the activity and selectivity in furan synthesis. 

The adipic acid process we have developed involves butadiene oxidative carbonylation in the presence of methanol, a l, l-dimethoxycyclohexane dehydration agent, and a palladium(ll)/ copper(ll) redox catalyst system (Equation 1.). The reaction sequence includes an oxycarbonylation, hydrogenation and hydrolysis step(17-19). The net result is utilization of butadiene, the elements of synthesis gas, l, -dimethoxycyclohexane and air to give adipic acid, cyclohexanone and methanol. 

V-containing silicalite, for example, has been shown to have different catalytic properties than vanadium supported on silica in the conversion of methanol to hydrocarbons, NOx reduction with ammonia and ammoxidation of substituted aromatics, butadiene oxidation to furan and propane ammoxidation to acrylonitrile (7 and references therein). However, limited information is available about the characteristics of vanadium species in V-containing silicalite samples and especially regarding correlations with the catalytic behavior (7- 6). 

Molecular modelling of butadiene oxidation by CYP2E1 has indicated that species differences in the kinetic parameters might be explained by a non-conservative change from Thr-437 to His-437 between rodents and humans and by a conservative change from Ile-438 to Val-438 (Lewis etal., 1997). 

Duescher, R.J. Elfarra, A.A. (1992) 1,3-Butadiene oxidation by human myeloperoxidase. Role of chloride ion catalysis of divergent pathways. J. biol. Chem.. 267, 19859-19865... 

Elfarra, A.A., Duescher, R.J. Pasch, C.M. (1991) Mechanism of 1.3-butadiene oxidations to butadiene monoxide and crotonaldehyde by mouse liver microsomes and chloroperoxidase. Arch. Biochem. Biophys., 286, 244-251... 

A consecutive reaction mechanism was proposed by Zhang-Lin et al. (25,26). The mechanism was based on kinetics data calculated for the oxidation of butane, 1-butene, 1,3-butadiene, and furan catalyzed by (VO)2P207 and VOPO4 phases. In conbast to the results of the TAP investigations, the kinetics data suggested that furan is not an intermediate in butane oxidation, but is an intermediate in butadiene oxidation. The differences observed in the oxidation of butane and the unsaturated hydrocarbons lead to questions about the validity of extrapolating butene and butadiene oxidation results to the butane oxidation. 

Russell, R. R., VanderWerf, C. A. Malonic ester synthesis with styrene oxide and with butadiene oxide. J. Am. Chem. Soc. 1947, 69,11-13. Mizuno, Y., Adachi, K., Ikeda, K. Condensed systems of aromatic nitrogenous series. XIII. Extension of malonic ester synthesis to the heterocyclic series. Pharmaceutical Bulletin 1954, 2, 225-234. 

It is interesting to compare the hydrolysis of butadiene oxide (10) with those of 1-chloro-2-butene and 3-chloro-l-butene.38 l-Chloro-2-butene (19a) solvolyzes in water to yield 45% of 2-butene-l-ol (22a) and 55% of 3-butene-2-ol (23a) (Scheme 7). 3-Chloro-l-butene (20a) also solvolyzes to yield alcohols 22a and 23a, but in a different ratio (34% 66%, respectively). The lifetime of the allylic carbocation intermediate 21a is therefore not sufficient to allow dissociation of chloride ion and equilibration of solvent about the carbocation. However, hydrolyses of 19b and 20b (R = CH3 instead of H) yield identical ratios of allylic alcohol products 22b and 23b (15% 85%, respectively).38 Allylic cation 21b, with a second methyl group to stabilize positive charge, must have a longer lifetime, which allows departure of the leaving group and equilibration of solvent about the carbocation. 

Whereas the hydrolysis of l-chloro-2-butene gives comparable yields of products from attack of solvent at both primary and secondary carbons, very little product from the acid-catalyzed hydrolysis of butadiene oxide 10 is formed from the attack of solvent at the primary carbon. The transition state for acid-catalyzed epoxide ring opening has a relatively reactant-like geometry, and therefore positive charge de-localization into the adjacent double bond at the transition state is expected to be less than that for allyl chloride hydrolysis. 

Laskin, A., H. Wang, and C. K. Law. 2000. Detailed kinetic modeling of 1,3-butadiene oxidation at high temperatures. Int. J. Chemical Kinetics 32 589-614. 

Duescher, R.J. and A.A. Elfarra (1994). Human liver microsomes are efficient catalysts of 1,3-butadiene oxidation Evidence for major roles by cytochrome P450 2A6 and 2E1. Arch. Biochem. Biophys. 311, 342-349. 

Block copolymers 53 Butadiene oxide/ethylene oxide 63 tm-Butoxy free mono-radical 88, 89, 97, 98... 

Burke, E. J. Brezinsky, K. Classman, I., "Preliminary High Temperature Studies of 1,3-Butadiene Oxidation" presented at the Eastern States Section/The Combustion Institute Meeting, Atlantic City, N.J., December 1982. 

Synonyms Epoxidized 1,2-polybutadiene Polybutadiene epoxidized Poly (butadiene) oxide Polyoil, epoxidized Formula [CH CHOCHCHJJCH CHCHCHJ,... 

Polybutadiene latex. See Polybutadiene Poly (butadiene) oxide. See Epoxidized polybutadiene... 

Mills PL, Nicole JF Multiple automated reactor systems (MARS). 2. Effect of microreactor configurations on homogeneous gas-phase and wall-catalyzed reactions for 1,3-butadiene oxidation, Ind Eng Chem Rjes 44 6453—6465, 2005b. 

Akimoto and Echigoya, based on their study of M0O3 + Ti02 catalyzed oxidation of butadiene, dihydrofuran (2, 5-DHF), and furan, argue that butadiene oxidizes to MA via two pathways ... 

Trost has utilized the same class of chiral ligands for the conversion of butadiene oxide (54) into a number of useful chiral building blocks, such as 57 (Scheme 14.11) [67, 68]. In the course of reaction optimization studies, naphthyl-substituted ligand 56 proved optimal and led to the formation of 57 in 96% ee (>99% ee after recrystallization). A powerful illustration of the synthetic utility of such optically active building blocks involved the synthesis of several medicinally important agents, including the tuberculostatic drug ethambutol (58) [68]. 

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