DE1222035B - Process for the preparation of isobutyl formate - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number: File number: Registration date: Display day:

C07c

German class: 12 ο - 11

1222035
B78485IVb / 12o
September 11, 1964
4th August 1966

It is known that the reaction of alcohols with carbon monoxide in the presence of alkali Preparing catalysts at elevated temperature and under elevated pressure formic acid esters permit. According to US Pat. No. 2,117,600, Example 2, isobutyl formate is obtained by Implementation of isobutanol at a temperature below 110 ° C, a pressure of about 400 at and using 4 weight percent sodium isobutylate. The response program contains but only about 85 percent by weight isobutyl formate and 15 percent by weight unreacted Isobutanol. Since isobutyl formate and isobutanol form an azeotrope boiling at 97.5 ° C Forming 12 percent by weight isobutanol is the separation of such a mixture by distillation not possible. Thus, the unreacted isobutanol cannot be returned to the process. Another disadvantage of the known procedure is that the alkaline catalyst is insoluble in the reaction mixture. Large amounts of catalyst, such as 4 weight percent, therefore contribute the continuous implementation of the process leads to annoying deposits in the reaction vessel.

According to the US patent mentioned above, methanol can be converted into Transfer 96% methyl formate (see. Example 1).

It has now been found that isobutyl formate can be obtained by reacting isobutanol with Carbon oxide in the presence of an alcoholate as a catalyst at elevated temperature and at elevated temperatures Pressure is obtained when 0.05 to 0.7 percent by weight, preferably 0.1 to 0.5 percent by weight, is based on isobutanol, sodium metal in the form of an alcoholate used as a catalyst and in a Pressure between 80 and 300 at, preferably between 150 and 200 at, and at a temperature below 90 ° C, preferably between 60 and 90 ° C, works.

With the new process, products are obtained with more than 90%, under particularly favorable conditions even with more than 98% isobutyl formate. The rest consists essentially of unreacted Isobutanol. In addition, there are still unknown by-products in amounts of a few tenth of a percent. Since the alkaline catalyst is only used in a small amount, the troublesome occur Deposits of the known process largely back.

As such, the conditions of the present process in terms of amount of catalyst, temperature and pressure for the production of ants are processes for the production of
Isobutyl formate

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Johannes Eberhard Schmidt,

Ludwigshafen / Rhine;

Dr. Walter Scheidmeir, Limburgerhof;

Dr. Horst Kerber,

Dr. Heinz Hohenschutz, Mannheim

acid methyl ester from German patent specification 1147 214 known. However, one also obtains as in the process of US Pat. No. 2117,600, only a 95- to 97% strength methyl formate. The reduction in the amount of catalyst from 4% sodium methylate in the case of the United States patent (cf. Example 1) to 0.7% sodium methylate in the case of German patent specification 1147 214 (cf. Example) does not change the methyl formate content of the reaction mixture. Surprisingly is, however, in the case of isobutyl formate by reducing the amount of catalyst and compliance with certain pressure and temperature conditions a significant increase in the Content of ester in the reaction mixture reached, namely from 85 to over 90%, in favorable cases even to over 98%.

The isobutyl alcohol should be as anhydrous as possible, since even small amounts of water lead to that the catalyst is converted into the inactive sodium formate. It is still recommended to have a to use as pure carbon dioxide as possible. In particular, sulfur compounds, carbon dioxide, If possible, ammonia and water vapor should not be present, as they act as catalyst poisons.

Sodium isobutoxide is best used as the catalyst. But it is also possible for others Use sodium alcoholates, for example sodium methylate, which is also in methanolic solution can be added. In this case, a certain amount of methyl formate is produced as a by-product, which, however, is easily separated from the isobutyl formate because of its low boiling point can be.

609 608/419

i 222 035

The process is carried out, for example, in a vertical high-pressure vessel, into which isobutyl alcohol, in which the alkali metal has been dissolved, is continuously introduced at the top. In the middle, carbon dioxide is introduced. The temperature in the reaction chamber is set by cooling held at the desired height. ^ © äs · ReaMorifcprö ^ iÄ-ziöM-'man continuously from the lower end of the reactor, which, with the exception of a small oaspolstersr ^, is completely filled with liquid. * The ¹ catalyst is neutralized by adding a small amount of acid, preferably formic acid, unless it has already been converted into sodium formate in the course of the reaction due to the presence of small amounts of water. In general, 0.05 to 2 percent by weight of acid is added to the reaction mixture. The neutralized reaction mixture then becomes isobutyl formate. obtained by simply aborting.

Isobutyl formate is known to be a paint solvent. ^: "-." .- '- ^: - - ■

The parts mentioned in the following examples are parts by weight. They relate to the parts of the room how grams to cubic centimeters.

B is ρ ie 1 1 .... - ..-

2000 parts of isobutanol, containing 4 parts of sodium dissolved, introduced. After heating to 70 ° C it will take that long pure carbon dioxide is pressed in until the pressure remains constant at 195 atm. During the implementation must the heat released can be dissipated by external or internal cooling. If not carbon dioxide more is absorbed, it is allowed to cool down and then relaxed. Then the reaction mixture transferred to a distillation vessel and added dropwise formic acid while stirring pH = 7 neutralized, for which about 4 parts of formic acid are required. Then from the solid catalyst residue distilled off. The yield of isobutyl formate (boiling point = 97-99 ° C.) is 2677 pieces. The composition of the distillate is according to the gas graphical analysis 98.3% isobutyl formate, 1.6% isobutanol and 0.1% unknown substances.

You work 'as in the example' !, 'put the isobutanol however, 10 parts of sodium are added. 2665 parts of end product are obtained with the same composition as in Example 1.··. ·· '■ - ■ -

Example 3

The procedure described in Example 1 is followed, each at a pressure of 150 atm and a temperature of 90 ° C. 2630 parts of distillate (boiling point = 96-97 ° C.) containing 93.9% isobutyl formate, 5%, are obtained 'Contains 9% isobutanol and 0.2% unknown substances'. ¹ ^ "■ ■ '· - · ^; ·· -' * '■ · ^: ■'

Example 4

Proceed as in the example · '! described, but adds 0.25 ^: percent by weight sodium to the isobutanol in the form of a 30% methanolic sodium dimethylate solution and carries out the reaction at 80.degree. The yield of distillate (bp = 32-98 ° C) is 2548 parts with the composition 94.09% isobutyl formate, 2.66% isobutanol, 3.07% methyl formate, 0.03% methanol and 0.15% unknown substances.

Claims (1)

Claim: Process for the preparation of isobutyl formate by converting isobutanol with carbon oxide in the presence of an alkali metal alcoholate as a catalyst at elevated temperature and under increased pressure, characterized in that 0.05 to 0.7 percent by weight, preferably 0.1 to 0.5 percent by weight, based on isobutanol, of sodium metal in the form of an alcoholate is used as a catalyst and at a pressure between 80 and 300 at, preferably between 150 and 200 at, and at a temperature below 90 ° C. 609 608/419 7.66 © Bundesdruckerei Berlin