Improvements in production of glycols

摘要

Glycols may be prepared by the hydration of an olefine oxide dissolved in water containing an acid hydration catalyst, preferably sulphuric acid, and the resulting glycol solution separated from the free acid and that portion of the acid which is in combination with the glycol and is not precipitated by addition of barium chloride, by passing the glycol solution through an anion absorbing resin. Any resin of the anion-absorbtion type may be used; they are, in general, the product of condensation of organic amines or similar basic materials with formaldehyde. As examples of commercially available resins, there may be mentioned one known as "Anex" which is believed to be a melamine resin and another known as "Amberlite IR-4" which is the condensation product of aromatic amines such as aniline with formaldehyde. The process may be carried out in the apparatus illustrated wherein a deep bed of the resin 6, which may be in the form of particles ranging in size from 16 to 50 mesh, is supported in a column 5. The glycol solution is introduced through a pipe 7 at a relatively low rate so that when the solution leaves the apparatus, via pipe 9, it will contain no free or combined acid. The operation is preferably carried out at room temperature. The spent resin may be regenerated by first flushing the bed with water to remove the glycol solution and then introducing an aqueous solution of sodium carbonate and finally rinsing the bed with water; suitable connections 10 and 11 are provided for this purpose. The acid-free glycol solution may be passed to a multiple effect evaporator and after concentration, distilled to recover the glycol. A reference is made to the preparation of ethylene glycol by the catalytic hydration of ethylene oxide as set forth in Specification 498,119.