CS233728B2 - Processing of isobutylene and methanole by decomposition of methyl 3 butylether - Google Patents

Abstract

A process for the decomposition of an alkyl tert-alkyl ether to produce the corresponding olefin and alcohol, is characterised in that the alkyl tert-alkyl ether is fed to a distillation column containing a catalyst suitable for the decomposition of the ether, the olefin produced being continuously withdrawn from the top of the column, and the bottom product consisting of pure alcohol or at least a mixture of alcohol and ether.

Description

The present invention relates to a process for the preparation of isobutylene and methanol by decomposition of methyl tert-butyl ether (ΜΊΒΕ). The mercuric alkali ethers are decomposed in order to obtain the corresponding oltefins in a high degree of purity. The decomposition and separation of the reaction mixture are complicated by problems which coincide with the easy dimerization of the olefins produced.

The olefins tend to provide dimerization products either in the liquid or gas phase.

It has now been found that it is possible to overcome the disadvantages of the prior art by making appropriate use of the difference in relative volatility between the olefin produced and the corresponding ether and alcohol.

SUMMARY OF THE INVENTION The present invention provides a process for the preparation of isobutylene and methanol by decomposing mlyHeTCbutyl ether, characterized in that meethΊler-butyltthec is fed to a tray distillation column containing on at least one floor a sulfonated stlceidinylbenzyl resin as a catalyst operating under pressure from 0.3 to 0.8 MPe and at a temperature corresponding to this pressure, the isobutylene produced is continuously removed from the top of the column and pure methanol or at least a mixture of methanol and methanol / methyl tert-butyl ether is removed from the bottom as product. the heat required to decompose bethulterc.butlletUtcu is supplied by vapors which at least partially condense on the tray or trays on which the catalyst bed is arranged, which vapors are generated on trays located below the tray or trays on which the catalyst bed is arranged.

Through the catalytic bed the liquid falls from the upper floors and the steam rises from the lower floors. The heat for decomposition of the butylbutyl is provided by the condensation of a portion of the vapors in the tray or tray on which the catalyst bed is arranged. Ether is given by ^{d to y} at the point Olon ^ ns is traveled by at least the amount ^{of p} atrophy than the highest ^{P s} atrophy, which is arranged on the catalyst bed.

As mentioned forming product ΘίΙοΗέίΐζβ ^ οί overhead isobutylene, while ^P ro ^d uct, ^kt projecting into the cavity from ⁱⁿ states in the ^p of ^dk for ^the Olon ^{y t} Voren ^b ud Cisy methanol or mixtures thereof with ^ rozložným ethers depending on the conditions under which the distillation procedure is carried out.

If the obtained mixture of methanol and ^gamma íeehulterc.but letUecu, it may preferably ether odddlit deesilscí. The recovered ether can then be recycled to decomposition and separation in a tray distillation column.

The invention is illustrated by the following example. This example is illustrative only and does not limit the scope of the invention in any way.

Example

A distillation column is made using flanged tube segments. The tubular segment has a diameter of 100 ounces and a length of 1,000 mm and comprises six cap-shaped floor trays, with two caps on each floor.

The column is formed by alternating tube segments filled with catalyst of length

000 mm with tubular segments containing six distillation trays. In total, the column comprises two tubular sections containing trays above the feed introduction point and six tubular sections below the feed introduction hearth. Of the six tube sections located below the feed point j, three are formed by tray segments and three catalyst segments, with tray segments and catalyst segments alternating. The catalyst is a sulfonated styrene-divinylbenzene resin Ambeeryst 15 (Rohm and Haas). %

1 kg of MOMO is added to the column per hour to which recycled methanol-MTBE mixture containing 50 g of methanol with 200 g of MTBE is added.

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A reflux ratio of 2: 1 is maintained in the column. The procedure is carried out from an absolute pressure of 0.5 MPa e at a temperature ranging from 45 to 110 ° C. The product leaving the top of the column contains 560 g of product containing 20 g of methanol and traces of dlisobutylene.

The bottom product contains 590 g of methanol and 200 g of MTBE.

The bottom product was fed to a second packed column operating at atmospheric pressure at a reflux ratio of 3: 1. The bottom product of the column contains 540 g of pure methanol and the top product of the column which is recycled to the first column contains 200 g of MTBE and 50 g of methanol.

Claims (1)

A process for the preparation of isobutylene and methanol by decomposition of methyl tert-butyl ether, characterized in that methyl tert-butyl ether is fed to a tray distillation column containing at least one floor sulfonated styrendivinylbenzene resin as a catalyst operating at a pressure of 0.3 to 0.8. The isobutylene produced is continuously removed from the top of the column at a temperature corresponding to this pressure and pure methanol or at least a mixture of methanol and methyl tert-butyl ether is removed from the bottom of the column, the heat required for decomposing methyl tert-butyl ether being supplied by ppr. they partially condense on the tray or trays on which the catalyst bed is arranged, which vapors are formed on trays located beneath the petroleum or on the trays on which the catalyst bed is arranged.