| 摘要 |
1,151,939. Diesters; diols. CELANESE CORP. 14 Sept., 1966 [23 Sept., 1965], No. 41075/66. Heading C2C. A mixture of monomeric hydroxy-esters, which can be hydrogenated to a diol mixture over a copper chromite catalyst, is obtained by mixing a stoichiometric excess of a C 4-8α,#- alkanediol with a mixture of acids obtained by the oxidation of cyclohexane, heating the reaction mixture to reflux while separating water vapour and organic compounds boiling below the b.pt. of the alkane diol and the pressure obtaining, passing the residual mixture through a reaction vessel divided by baffles or packing into a series of successive reaction zones, or through successive reaction vessels, so as to avoid back mixing, while maintaining the reaction zone or zones at an elevated temperature and at a pressure of 50-760 mm. HgA and continuously withdrawing vapours of the water produced and organic compounds boiling below the b.pt. of the alkane diol under the conditions obtaining without permitting the withdrawn vapours to pass through the liquid in any other reaction zone or vessel, and withdrawing the resultant ester mixture after a residence time sufficient to reduce the acid content thereof to below 1À0% by wt. The starting acid mixture contains adipic, glutaric, succinic, hydroxycaproic and formylvaleric acids. By stoichiometric excess is meant one mole of diol per mole carboxylic group in the acid mixture. The final esterification stage is preferably effected at 200-300‹ C. for 2-6 hours. Examples relate to the preparation of 1,6-hexane diol esters and the reduction thereof to 1,4-, 1,5- and 1,6-diols. |
