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Method for the manufacture of methyl tertiary butyl ether from tertiary butyl alcohol and methanol

  • US 5,811,597 A
  • Filed: 08/26/1996
  • Issued: 09/22/1998
  • Est. Priority Date: 08/26/1996
  • Status: Expired due to Fees
First Claim
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1. A process for the preparation of methyl tertiary butyl ether from methanol and tertiary butyl alcohol contaminated with oxygen-containing impurities which comprise the steps of:

  • a) charging tertiary butyl alcohol contaminated with oxygen-containing impurities to a reactive distillation column containing a bed of a tertiary butyl alcohol dehydration catalyst to decompose the oxygen-containing contaminants, to dehydrate a portion of the tertiary butyl alcohol to form isobutylene and water, and to separate the dehydration reaction products in the reactive distillation column into a lower boiling isobutylene fraction and a higher boiling aqueous tertiary butyl alcohol fraction;

    b) distilling the higher boiling aqueous tertiary butyl alcohol fraction in a first distillation column to form a first lower boiling tertiary butyl alcohol fraction and a first higher boiling water fraction;

    c) charging the lower boiling isobutylene fraction, the first lower boiling tertiary butyl alcohol fraction and methanol to an etherification reactor to form an etherification reaction product comprising unreacted methanol, unreacted tertiary butyl alcohol, water, isobutylene and methyl tertiary butyl ether;

    d) distilling the etherification reaction product in a second distillation column to provide a second lower boiling isobutylene fraction comprising isobutylene, methanol and methyl tertiary butyl ether and a second higher boiling methanol distillation fraction comprising methanol, tertiary butyl alcohol and water;

    e) charging the second lower boiling isobutylene fraction to a methanol solvent extraction tower for countercurrent contact with water to form a raffinate comprising MTBE, isobutylene and water and an extract comprising MTBE, methanol and water;

    f) charging the raffinate to a third distillation column and separating it therein into a third higher boiling MTBE product fraction and a third lower boiling aqueous isobutylene fraction;

    g) charging the third lower boiling aqueous isobutylene fraction to a decantation zone and separating it therein into an isobutylene chase and water;

    h) charging the isobutylene phase and methanol to an isobutylene conversion reactor and reacting the isobutylene with methanol to form an isobutylene conversion product comprising methyl tertiary butyl ether, unreacted methanol, unreacted isobutylene and tertiary butyl alcohol; and

    i) recovering MTBE from the etherification reaction product and the isobutylene conversion product.

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