Preparation of polyoxymethylene dimethyl ethers by acid-activated catalytic conversion of methanol with formaldehyde formed by dehydrogenation of methanol
First Claim
1. A process for the catalytic production of a mixture of oxygenated organic compounds suitable as a blending component of fuel for use in compression ignition internal combustion engines, which process comprises providing a feedstream comprising methanol, a soluble condensation promoting component capable of activating a heterogeneous acidic catalyst, and a source of formaldehyde formed by the conversion of methanol in the presence of a catalyst comprising copper and zinc as catalyst components which source of formaldehyde comprises from about 30 to about 85 percent by weight formaldehyde in methanol solution containing less than about 5 percent water;
- heating the feedstream with the heterogeneous acidic catalyst under conditions of reaction sufficient to form an effluent of condensation comprising water, methanol, methylal and one or more polyoxymethylene dimethyl ethers which methylal and polyoxymethylene dimethyl ethers have structures represented by the formulaCH3O(CH2O)nCH3where n is a number from 1 to about 10; and
contacting at least a liquid portion of the effluent with an anion exchange resin to form an essentially acid-free mixture comprising methylal and polyoxymethylene dimethyl ethers having values of n greater than 1.
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Abstract
A particularly useful process which includes the steps of providing a feedstream comprising methanol, a soluble condensation promoting component capable of activating a heterogeneous acidic catalyst and a source of formaldehyde formed by conversion of methanol in the presence of a catalyst comprising copper and zinc; and heating this feedstream with the heterogeneous acidic catalyst in a catalytic distillation column to convert methanol and formaldehyde present to methylal and higher polyoxymethylene dimethyl ethers and to separate the methylal from the higher polyoxymethylene dimethyl ethers is disclosed. Advantageously, methylal and higher polyoxymethylene dimethyl ethers are formed and separated in a catalytic distillation column. By including within the column a section containing an anion exchange resin, an essentially acid-free product is obtained. Products can be used directly as a blending component, or fractionated, as by further distillation, to provide more suitable components for blending into fuel.
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Citations
14 Claims
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1. A process for the catalytic production of a mixture of oxygenated organic compounds suitable as a blending component of fuel for use in compression ignition internal combustion engines, which process comprises providing a feedstream comprising methanol, a soluble condensation promoting component capable of activating a heterogeneous acidic catalyst, and a source of formaldehyde formed by the conversion of methanol in the presence of a catalyst comprising copper and zinc as catalyst components which source of formaldehyde comprises from about 30 to about 85 percent by weight formaldehyde in methanol solution containing less than about 5 percent water;
- heating the feedstream with the heterogeneous acidic catalyst under conditions of reaction sufficient to form an effluent of condensation comprising water, methanol, methylal and one or more polyoxymethylene dimethyl ethers which methylal and polyoxymethylene dimethyl ethers have structures represented by the formula
CH3O(CH2O)nCH3 where n is a number from 1 to about 10; and
contacting at least a liquid portion of the effluent with an anion exchange resin to form an essentially acid-free mixture comprising methylal and polyoxymethylene dimethyl ethers having values of n greater than 1.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- heating the feedstream with the heterogeneous acidic catalyst under conditions of reaction sufficient to form an effluent of condensation comprising water, methanol, methylal and one or more polyoxymethylene dimethyl ethers which methylal and polyoxymethylene dimethyl ethers have structures represented by the formula
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10. A process for the catalytic production of a mixture of oxygenated organic compounds suitable as a blending component of fuel for use in compression ignition internal combustion engines, which process comprises providing a feedstream comprising methanol, a soluble condensation promoting component capable of activating a heterogeneous acidic catalyst, and a source of formaldehyde formed by the conversion of methanol in the presence of a catalyst comprising copper and zinc as catalyst components which source of formaldehyde comprises from about 30 to about 85 percent by weight formaldehyde in methanol solution containing less than about 5 percent water;
- heating the feedstream with the heterogeneous acidic catalyst under conditions of reaction sufficient to form an effluent of condensation comprising water, methanol, methylal and one or more polyoxymethylene dimethyl ethers which methylal and polyoxymethylene dimethyl ethers have structures represented by the formula
CH3O(CH2O)nCH3 where n is a number from 1 to about 10;
contacting at least a liquid portion of the effluent of condensation with an anion exchange resin to form an essentially acid-free mixture; and
fractionating the acid-free mixture as by distillation to obtain an overhead fraction containing methylal and an essentially methylal-free bottom fraction containing polyoxymethylene dimethyl ethers having values of n greater than 1, and further comprises formation of the feedstream by a process comprising continuously contacting methanol in the vapor phase with a catalytically effective amount of a catalyst consisting of copper, zinc and a member selected from the group consisting of sulfur, selenium and tellurium as catalyst components at elevated temperatures to form a gaseous dehydrogenation mixture comprising formaldehyde, dihydrogen and carbon monoxide;
cooling the gaseous dehydrogenation mixture with a liquid comprising methanol to take up and hold formaldehyde therein; and
separating a gaseous mixture, comprising predominantly dihydrogen and carbon monoxide, from resulting liquid comprising methanol, formaldehyde and formic acid.- View Dependent Claims (11, 12, 13, 14)
- heating the feedstream with the heterogeneous acidic catalyst under conditions of reaction sufficient to form an effluent of condensation comprising water, methanol, methylal and one or more polyoxymethylene dimethyl ethers which methylal and polyoxymethylene dimethyl ethers have structures represented by the formula
Specification