| 摘要 |
An aliphatic secondary alcohol containing 6 to 40 carbon atoms is prepared by reacting the corresponding paraffin with molecular oxygen in the presence of a trialkoxyboroxine, hydrolysing the resulting boron containing ester to form aqueous boric acid and a secondary alcohol. Suitable trialkoxyboroxines include those wherein the alkoxy substituent contains 4 or more carbon atoms and has either at least two carbon atoms less than the paraffin, when the paraffin has less than 10 carbon atoms, or at least 4 carbon atoms less than the paraffin, when the paraffin has at least 10 carbon atoms. The oxidation step may be carried out at elevated temperature and under pressures greater than or equal to atmospheric optionally in the presence of a catalytic amount of a heavy metal compound such as an organic salt of cobalt, manganese, lead or iron which is soluble in the reaction mixture. Preferably at least part of the trialkoxyboroxine is obtained by partially hydrolysing a trialkyl borate ester (formed from aqueous boric acid and an alkanol of at least 4 carbon atoms), optionally in a solution of the paraffin to be oxidized, at a temperature from 130 DEG to 225 DEG C. in the presence of water vapour at a partial pressure of at most 250 mm. of Hg. The entire process may be carried out batchwise or continuously, the ketone by-product and unoxidized paraffin being removed from the intermediate boron containing ester prior to hydrolysis with water to give the desired secondary alcohol mixed with aqueous boric acid which may be re-converted to a trialkyl ester for re-use particularly in the specified continuous mode of operation. The oxidation of dodecane to a secondary alcohol together with the corresponding ketone and diol by-products is described. Tri-(n-butoxy) boroxine is prepared by controlled partial hydrolysis at elevated temperature of tri-(n-butyl) orthoborate in an atmosphere of nitrogen and water vapour. Tri-(n-butyl) orthoborate is prepared by esterification of aqueous boric acid.
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