JPS6028429A - Catalyst for preparing polyethylene glycol dialkyl ether - Google Patents

Abstract

PURPOSE:A catalyst useful for preparing a polyethylene glycol dialkyl ether from a polyethylene glycol monoalkyl ether, obtained by supporting nickel and rhenium on a gamma-alumina carrier. CONSTITUTION:A polyethylene glycol monoalkyl ether shown by the formula I (R is <=4C alkyl; n>=2) is reacted with hydrogen in the presence of a catalyst obtained by supporting nickel and rhenium on a gamma-alumina carrier (preferably having 100-250m<2>/g specific surface area) (preferably catalyst having 5-50wt% nickel based on gamma-alumina carrier, and an atom ratio of nickel to rhenium of (1:0.005)-(1:0.3), to give a polyethylene glycol dialkyl ether shown by the formula II. EFFECT:Improving the yield of a polyethylene glycol dialkyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel catalyst used in producing polyethylene glycol dialkyl ether by reacting polyethylene glycol monoalkyl ether in the presence of hydrogen. More specifically, a polyethylene glycol monoalkyl ether represented by the general formula (1) % formula % (1) (wherein R is an alkyl group having 4 or less carbon atoms, n≧2) is reacted in the presence of hydrogen, General formula (II) n-(0CH2CH2)rL-8-OCH8(II)
The present invention relates to a characteristic catalyst used in producing polyethylene glycol dialkyl ether shown in the following.

Polyethylene glycol dialkyl ether is used in a wide range of fields such as gas absorbents, gas purification, paints, inks, solvents, reaction solvents, extractants, electrolytes, antifreezes, and brake fluids.

The method for producing the polyethylene glycol dialkyl ether represented by the general formula (■) from the polyethylene glycol monoalkyl ether represented by the general formula (I) is conventionally known. Alternatively, the reaction may be carried out in the presence of a catalyst in which palladium, platinum, rhodium, ruthenium, iridium, or a component thereof is supported on a carrier such as alumina, silica, or activated carbon.

The production of polyethylene glycol monoalkyl ether represented by general formula (1) and polyethylene glycol dialkyl ether represented by general formula (n) proceeds according to the following sequential reactions (III) and (IV). )rL-OH-+R-(OCHz
CHt)n9rCH2CHO+H2(n')R-(OC
H2CHt) CH, CHO→R-(OCH2CH2)
fL, p, parts, +co (tv) Therefore, in addition to the desired methyl ether, the reaction solution contains an aldehyde compound and an ethoxylate of 2 or less as a side reaction product.

Further, the reaction decomposition gas contains methane, ethane, carbon dioxide, etc. in addition to hydrogen and carbon monoxide, and among these, carbon oxide is particularly adsorbed to nickel and can become a strong catalyst poison. Therefore, an excellent catalyst for use in the production of polyethylene glycol dialkyl ether is the reaction (III
) and (IV), and must be resistant to carbon monoxide poisoning.

Catalysts for the production of polyethylene glycol dialkyl ether that have been proposed in the past, for example, in Japanese Patent Publication No. 49-25246, include nickel alone, nickel as a main component with additions of copper, chromium, etc. U.S. Patent No. 3,428,692 describes a method in which the components are supported on a carrier such as chromia or cinnabar earth, and a method in which palladium alone or palladium with other elements added is supported on a support such as alumina or carbon. is nickel, cobalt or oxides of these metals or Raney nickel, West German Patent Publication No. 290027
No. 9 includes palladium, platinum, ruthenium, rhodium,
Iridium and mixtures thereof can be combined with silica, alumina,
West German Patent Publication No. 3025190 describes palladium, platinum, rhodium and mixtures thereof supported on alumina, silica, etc.
For example, 0.1 to 1% of it is supported on a carrier such as carborundum or activated carbon.

However, these conventionally known catalysts are not sufficient in both activity and selectivity.

Therefore, an object of the present invention is to provide a novel highly active catalyst for producing polyethylene glycol dialkyl ether represented by general formula (II) in good yield from polyethylene glycol monoalkyl ether represented by general formula (1). It is to be.

The present inventors have conducted intensive studies on the development of an industrially practical catalyst for producing polyethylene glycol dialkyl ether and a method for producing the same. As a result, the present inventors have found that a catalyst in which nickel and rhenium are supported on a γ-alumina carrier has a high The present invention was completed based on the discovery that the catalyst is active and highly selective, easily converts generated CO into CH, suppresses adsorption and poisoning, and is more useful than conventionally known catalysts.

The present invention is characterized by reacting polyethylene glycol monoalkyl ether represented by the general formula (1) % formula % (1) (in the formula, R is an alkyl group having 4 or less carbon atoms, R≧2) in the presence of hydrogen. , when producing a polyethylene glycol dialkyl ether represented by the general formula (If) 几-(OCH2CH2)-ocHs (It), the catalyst used is characterized in that nickel and rhenium are supported on a γ-alumina carrier. A catalyst for producing polyethylene glycol dialkyl ether is disclosed.

The polyethylene glycol monoalkyl ether represented by the general formula (1) % formula % (in the formula, R is an alkyl group having 4 or less carbon atoms, R≧2) used as a raw material of the present invention, R is a methyl group, ethyl group, leupropyl group, isopropyl group, leubutyl group, isobutyl group, 5ec-
Examples include diethylene glycol, triethylene glycol, and tetraethylene glycol monoalkyl ether, which are butyl and tert-butyl groups.

The γ-alumina support used in the present invention has a specific surface area of 20 to 3
5077? /f γ-alumina support, especially 100~zs
A γ-alumina carrier of o77(/r) is preferred. The carrier may have a wide variety of shapes, such as pellets, spheres, grains, cylinders, rings, and powders.

The purpose of the invention can only be achieved in the catalyst of the invention if nickel and rhenium are supported on a γ-alumina support. In this case, the three components of the γ-alumina support, nickel, and rhenium are essential, and a catalyst that supports nickel or rhenium alone has significantly inferior activity and selectivity compared to a catalyst that supports both of them.

Catalysts using other carriers such as diatomaceous earth, activated carbon, and silica alumina are also significantly inferior in activity and selectivity compared to catalysts using γ-alumina carriers.

The amounts of nickel and rhenium contained in the catalyst of the present invention can vary over a wide range, with the nickel being 5 to 50% by weight of the r-alumina support and the atomic ratio of nickel to rhenium being 10.005 to 50% by weight. Good results are given when the ratio is within the range of 1:0.3.

The raw material compounds for nickel supported on the γ-alumina carrier of the present invention include inorganic salts such as nitrates, sulfates, carbonates, oxides, and hydroxides, and acetates, oxalates, citrates, and lactates. Examples include organic salts such as In particular, highly water-soluble salts are preferred. As a raw material compound for rhenium,
It is preferably used in the form of ammonium perrhenate, rhenium peroxide, etc.

The catalyst for producing polyethylene glycol dialkyl ether of the present invention is produced as follows.

A γ-alumina support is immersed in an aqueous medium in which nickel and rhenium compounds are dissolved to support the required amount, and dried at 50 to 150°C, preferably 180 to 120°C, and then directly heated to 200 to 450°C. , preferably with hydrogen or a hydrogen-containing gas at a temperature range of 250-350° C. to obtain the finished catalyst.

The catalyst of the present invention is usually formed into a fixed bed or a suspended bed, and is prepared in the presence of hydrogen in a liquid phase or a gas phase at a temperature of, for example, 150°C.
It can be used for the production of polyethylene glycol dialkyl ether under the reaction conditions of ~300°C, normal pressure ~50 kg/do, and a molar ratio of hydrogen to polyethylene glycol monoalkyl ether supplied to the reactor of 2 to 30, but it is highly active. Therefore, compared to conventionally known catalysts, milder reaction conditions can be employed to produce polyethylene glycol dialkyl ether in high yield.

The catalyst having excellent characteristics according to the present invention will be explained in more detail by the following Examples and Comparative Examples, but the present invention is not limited to these Examples.

Circulation Example 1 A cylindrical γ-alumina carrier 100d with a specific surface area of 200 m”/t, a diameter of 1.5 B, and a length of 4 mW was coated with nitric acid (N' (No, )25H20) 8.
46y, was impregnated with 22ml of an aqueous solution containing 2.7Of ammonium perrhenate, and dried at 100°G for 1 hour.

and Q catalyst were subsequently subjected to hydrogen reduction treatment at 300° C. for 2 hours in a hydrogen gas atmosphere. The content of each metal in this catalyst was 16.8% by weight of nickel with respect to the γ-alumina support, and an atomic ratio of rhenium with respect to nickel of 0.05.

The above catalyst 30WLt and diethylene glycol monomethyl ether 1002 were placed in a stainless steel autoclave with an internal volume of 0.51 and equipped with an electromagnetic stirrer, and the rate was 1701/min. L
190℃, 20kg/c/LG while introducing 1 H2
The mixture was allowed to react for 8 hours. As a result of analyzing the reaction product liquid, the conversion rate of diethylene glycol monomethyl ether was 85 molar, and the selectivity to ethylene glycol dimethyl ether was 82.
It was Momoru.

Example 2 Using the catalyst shown in Example 1, triethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1. Analysis of the reaction product solution revealed that the conversion rate of triethylene glycol monomethyl ether was 89 moles and the selectivity of diethylene glycol dimethyl ether was 87 moles.

Example 3 Using the catalyst shown in Example 1, tetraethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1. As a result of analyzing the reaction product liquid, the conversion rate of tetraethylene glycol monomethyl ether was 92 mmol,
Selectivity of triethylene glycol dimethyl ether 89
It was Momoru.

Example 4 A tube with an inner diameter of 25 mWL and a height of 2 m was used as a reactor, filled with 6 ooml of the catalyst shown in Example 1, and into which triethylene glycol monomethyl ether at λ 02/hour and H2 at 1311/hour were fed. and set the reaction temperature to 2
oo℃, operating pressure 20kg/CI! I kept it at G and allowed it to react. Analysis of the reaction product solution revealed that the conversion rate of triethylene glycol monomethyl ether was 87 moles and the selectivity of diethylene glycol dimethyl ether was 85 moles. The reaction product solution was analyzed after about 30 days while the reaction continued, and as a result, a conversion rate of triethylene glycol monomethyl ether of 85 moles and a selectivity of diethylene glycol dimethyl ether of 86 moles were obtained. This result shows that the activity of the catalyst of the present invention decreases very slowly.

Example 5 Using the catalyst shown in Example 1, diethylene glycol monoethyl ether was reacted under the reaction conditions shown in Example 1. Analysis of the reaction product solution revealed that the conversion rate of diethylene glycol monoethyl ether was 86 moles and the selectivity of ethylene glycol methyl ethyl ether was 83 moles.

Example 6 Using the catalyst shown in Example 1, a polyethylene glycol monomethyl ether mixture having a distribution of 4 to 12 where R is a methyl group in general formula (I) was reacted under the reaction conditions shown in Example 1. I forced it. As a result of analysis of the reaction product solution, the conversion rate of the polyethylene glycol monomethyl ether mixture was 99 moles or more, and the selectivity of polyethylene glycol dimethyl ether having a 3-110 group distribution where R is a methyl group in the general formula (I [)] was 95 moles.

Comparative Example 1 Diethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1 using a catalyst in which the catalyst carrier shown in Example 1 was replaced with a silica alumina carrier. Analysis of the reaction product liquid revealed that the conversion rate of diethylene glycol monomethyl ether was 62 moles and the selectivity of ethylene glycol dimethyl ether was 54 moles.

Comparative Example 2 Diethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1 using the catalyst shown in Example 1 without the addition of rhenium. Analysis of the reaction product liquid revealed that the conversion rate of diethylene glycol monomethyl ether was 59 moles and the selectivity of ethylene glycol dimethyl ether was 76 moles.

Comparative Example 3 Using a catalyst in which copper and chromium were added in an amount of 5% by weight relative to nickel instead of rhenium in the catalyst shown in Example 1, diethylene glycol monomethyl ether was prepared in Example 1.
Under the reaction conditions shown in L/7/recall dimethyl ether, the selectivity was 74 moles.

Comparative Example 4 Cobalt was added to the γ-alumina support shown in Example 1 by 16.5%.
Diethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1 using a catalyst supported at 8% by weight. Analysis of the reaction product solution revealed that the conversion rate of diethylene glycol monomethyl ether was 53 moles and the selectivity of ethylene glycol dimethyl ether was 52 moles.

Comparative Example 6 Palladium was added to the γ-alumina carrier shown in Example 1 in an amount of 0.0%.
Diethylene glycol monomethyl ether was reacted under the reaction conditions shown in Example 1 using a catalyst supported at 5% by weight. Analysis of the reaction product solution revealed that the conversion rate of diethylene glycol monomethyl ether was 36 moles and the selectivity of ethylene glycol dimethyl ether was 78 moles.

Claims (1)

[Claims] (1) Polyethylene glycol monoalkyl ether represented by the general formula (I) R-(OCR2CM, )-〇H (1) (wherein R is an alkyl group having 4 or less carbon atoms, R≧2) is hydrogenated. When producing a polyethylene glycol dialkyl ether represented by the general formula (I[) R-(0CH2CH2), t-0CHs (II) by reacting in the presence of A catalyst for producing polyethylene glycol dialkyl ether, characterized in that it supports.