GB1051089A - - Google Patents

Abstract

1,051,089. Sulpholane purification. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. July 5, 1965, No. 28295/65. Heading C2C. A sulpholane containing sulpholene, particularly one produced by the hydrogenation of a 3-sulpholene, especially in the presence of an aliphatic alcohol, as hereafter defined, is purified, by a, process which comprises contacting with an aliphatic alcohol, in the presence of an amount of a basic substance, especially with an alkali metal, e.g. Na, or alkaline earth metal hydroxide, such that the pH of the sulpholane/ alcohol mixture when diluted with an equal volume of water is at least 8, and preferably 10 to 14, whereby the sulpholene in said mixture is converted to the sulpholanyl ether of said alcohol, and thereafter recovering purified sulpholane from the resulting mixture by distillation. Aliphatic alcohol is defined as a monohydric alcohol, the sulpholanyl ether of which is substantially non-volatile or has a boiling-point sufficiently different from the boiling point of the sulpholane from which it is to be separated. The example describes the purification of sulpholane in a 40% by weight concentration in isopropanol as obtained by the hydrogenation of 3-sulpholene with Raney Ni catalyst, followed by the destruction of the free sulphur dioxide with hydrogen peroxide and neutralization of the sulphur trioxide with aqueous sodium hydroxide. Additional sodium hydroxide was added to effect the sulpholene conversion after which the products were separated by distillation.