Hexane-2,5-diol

The production of alcohols by the catalytic hydrogenation of carboxylic acids in gas-liquid-particle operation has been described. The process may be based on fixed-bed or on slurry-bed operation. It may be used, for example, for the production of hexane-1,6-diol by the reduction of an aqueous solution of adipic acid, and for the production of a mixture of hexane-1,6-diol, pentane-1,5-diol, and butane-1,4-diol by the reduction of a reaction mixture resulting from cyclohexane oxidation (CIO). 

Cyclic carbonates are not commercially available and have to be synthesized prior to use. As a result, commercially available carbonates such as diethyl carbonate [55-57] or diphenyl carbonate [93] were evaluated in polycondensation reactions with diols to prepare polycarbonates since they allow a broader spectrum of polymers to be accessed. Unfortunately, polymerizations employing diethyl carbonate require the use of an excess diethyl carbonate [55]. Nevertheless, polymers with molecular weight of 40kDa were achieved within 16 h. Also, the polymerization of diphenyl carbonate with butane-1,4-diol or hexane-1,6-diol via the formation of a cyclic dimer produced polymers with molecular weights ranging from 119 to 339kDa [93]. 

Hexane-1,6-diol was found to undergo an oxidation-cyclization process at elevated temperatures (250 °C) in the presence of a Cu-Cr catalyst supported on kieselguhr to yield 2,3,4,5-tetrahydrooxepin (68) (65JOC335). The final stage of the latter reaction involves a dehydration of the hemiacetal 2-hydroxyoxepane (75) as indicated in equation (38). An alternative type of base-induced cyclization (equation 39) involving intramolecular nucleophilic attack has been used in the synthesis of 4-ethoxycarbonyI-2,3,6,7-tetra-hydrooxepin (153) (73JOC1767). 

Similar methods can also be used for seven-membered and larger rings however, high dilution techniques must often be utilized. Oxepane, for example, is obtained by the dehydration of hexane 1,6-diol (80BCJ3031). 

Cyclodehydration of hexane-1,6-diol with tin phosphate as a catalyst (230°C) gives oxepane in 32% yield <2001GC143>. Acid-catalyzed dehydration of 2,2 -bis(hydroxydiphenylmethyl)biphenyl by an ion-exchange resin allows one to prepare a sterically hindered 2,2,7,7-tetraphenyldibenzo[c, ]oxepine in 70% yield under mild conditions (CH2C12, rt) <2002J(P1)2673>. 

Note. (1) These reaction conditions are used for the oxidation of decan-l-ol, hexane-1, 6-diol and oct-2-yn-l-ol. In the case of alcohols where acid-sensitive groups are also present (e.g. tetrahydropyranyl ethers), sodium acetate is added to buffer the reaction mixture alternatively pyridinium dichromate may be used.99... 

Figure 7. Comparison of observed XRD patterns of ZSM-5 synthesized with different directing agents. [TPA- tetra-propylammonium bromide, PIPZ- piperazine, HXDM- hexane-1, 6-diamine, HXDL- hexane-1,6-diol, and Na- organic free.] (Reproduced with permission from ref. 17. Copyright 1986 Butterworth.)...

Currently the global production of hexamethylenediamine exceeds 1.2 Mt/a and production (e.g. ICI, BASF and Rhone-Poulenc in Europe) is based on the hydrogenation of adiponitrile, largely obtained by catalytic addition of HCN to butadiene. Celanese produced hexamethylenediamine by reaction of ammonia with hexane-1,6-diol, coming from the hydrogenation of adipic acid. However, production by this method was abandoned in 1984. 

A copolymer was obtained on reaction of 1,1 -bis(iodomethyl)cyclopropane with the bis(sodium alkoxide) of hexane-1,6-diol. ... 

Mori s synthesis of 11 in 1974 was also convergent, as shown in Figure 1.8.25 In this synthesis, the C-C bond at between C-6 and C-7 was disconnected to enable the use of two cheap C6 starting materials, sorbic acid and hexane-1,6-diol. The former was converted to the building block A, while the latter was... 

Diols (H2L) Propane-1,2-diol Propane-1,3-diol Butane-2,3-diol Hexane-1,6-diol Pinacol... 

The rate of oxidation of hexane-1,6-diol (Behari et al. 1982a) by Ce(IV) has also been investigated in sulfuric acid media. Straightforward second-order kinetics (first order in both [Ce(IV)] and [diol]) appears to be appropriate in the molar sulfate/per-chlorate solutions. Based on the observed acid and bisulfate ion dependence, the authors conclude that the two reactive Ce(IV) species are CeSO and Ce(S04)2, which react with the diol in an outer-sphere electron transfer reaction... 

CAS 629-11-8 EINECS/ELINCS 211-074-0 Synonyms 1,6-Dihydroxyhexane HDO Hexametbylenediol 1,6-Hexanediol Hexane-1,6-diol a-co-Hexanediol Empiricai CeH Oj Formuia H0(CH2)60H... 

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