DE1196185B - Process for the preparation of N-tertiary butylformamide - 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-16

1196 185
F22828IVb / 12o
April 13, 1957
July 8, 1965

The invention relates to a process for the preparation of N-tert-butylformamide by reaction of about 1 mole of isobutylene with about 1 mole of hydrogen cyanide in the presence of sulfuric acid and Neutralizing the acidic reaction mixture.

It is already known to use various olefins with hydrogen cyanide in the presence of an equimolecular Amount of almost concentrated sulfuric acid or another catinoid compound. It has been found, however, that when this reaction is applied to a secondary or tertiary olefin low yields of less than 50% of the desired formamides can be achieved.

It is also known to produce formamides by reacting hydrogen cyanide in the presence of strong acidic condensing agents, with the exception of Alumi-τ niumchloridj can act on hydrocarbons with an olefinic double bond and the obtained addition products hydrolyzed to the corresponding formamides.

There is also a process for the production of 1,8-diamino-p-menthane known, which consists in j that one reacts with a mixture in the presence of water, hydrogen cyanide and sulfuric acid, which consists of limonene (dipentene), terpineol, ^ -terpineol, terpinhydrai and a-pinene

You also have 2,5-diamino-2,5-dimethylhexane made from bimethallyl and hydrogen cyanide in the presence of sulfuric acid, with a The amount of water used is 0.1 to 5 times the weight of the sulfuric acid used.

Using these known methods to produce N-tertiary butylformamide, one obtains only relatively low yields. Surprisingly, it has now been found that the yield can be reduced on N-tertiary batylformamide considerably verbes process for the production of N-tert-butylformamide

Applicant:

The Firestone Tire & Rubber Company,

Akron, Ohio (V. St. A.)

Representative:

Dipl.-Ing. K. Lengner, patent attorney,

Hamburg 26, Jordanstr. 7th

sern, if you look at the production of N-tertiary-butylformamide by reacting about 1 mole of isobutylene with about 1 mole of hydrogen cyanide in the presence of sulfuric acid and neutralizing of the acidic reaction mixture is carried out in such a way that the isobutylene is at a temperature from 20 to 25 ° C gradually the sulfuric acid, the 13 to 18% water and part of the required Contains amount of hydrogen cyanide, adds, then the remaining amount of hydrogen cyanide simultaneously with the isobutylene of the acidic mixture is also gradually added, followed by the reaction mixture heated to about 60 ° C and the hydrogen cyanide in molar excess at greater speed as the isobutylene introduces into the acidic solution and the molar ratio of isobutylene to sulfuric acid-1: 1.5-bis Is 1: 2.5. -

The reaction mixture is preferably neutralized with an aqueous ammonia solution.

The reaction takes place according to the following reaction scheme:

CH ₃

CH ₃ -C = CH ₂ + HCN + H ₂ SO ₄
CH ₃

aqueous H ₂ SO ₄ as a catalyst

+ 2NH ₄ OH or another base CH ₃ -C-CH ₃

N = CHOSO ₃ H: '.
CH ₃

CH ₃ -C-CH ₃ + (NH ₄ ) ₂ SO ₄ + H ₂ O
NHCH

509 599/427

3 4

After the neutralization, the ammonium is left to stand. After neutralizing the reactant sulfate solution from the organic liquid tion mixture with ammonia, extracting with separated and then recovering the ammonium sulfate from the ether, drying over anhydrous sodium carbonate solution. If necessary, organic distillation and distillation gave 93.8 g of N-tertiary-butylform solvents, such as benzene, toluene, gasoline, 5 amide (92.9% of theory).
Petroleum ether or hexane, either during the order of mixing the reaction setting or during the following neutralization participants for the obtained yield of N-tertiary reaction mixture are added. Butylformamide is crucial

The method of the invention is carried out by the following experiment, the corresponding one Embodiments explained in more detail. In accordance with the information in U.S. Patent 2,632,023

was done by using isobutylene instead of there

Example 1 used bimetallyls was used. Since Iso

butylene at the reaction temperature specified there

A 500 cm ³ three-necked flask was is gaseous with door of 15 to 50 ° C, it was erfordereinem gas inlet tube, tightly inserted stirrer 15 lent to go down to the reaction temperature, and provided with a Y connector which was added to the test in the following manner through a reflux condenser and to another inlet:

Filling funnel with a small reflux condenser led, a 500 cm ³ three-necked flask was with

both condensers were fed with water which was cooled to 10 ° C. dropping funnel, reflux condenser with cold alcohol. 1 mol of 87% sulfuric acid 20 (-18 ⁰ C) and effective mechanical stirrer, the concentration provided by mixing. The flask was cooled with dry ice 102 g of 96% sulfuric acid with 10.5 g of water and then with 30.0 g (0.535 g-mol) of isobutylene (suspended, was filled into the flask. 22 cm ³ of usual purity) and 18.14 g (0.671 g-mol) (0.57 mol) of liquid hydrogen cyanide were charged into the anhydrous hydrocyanic acid. Given the small funnel. The 500-cm ³ flask 35 temperature of the flask with an ice bath was immersed in an ice bath and brought one-fourth to 0 ° C, and then were rapidly the hydrogen cyanide was added. While stirring, 12.08 g (0671 g-mol) water was added. While the temperature was kept at 20 to 25 ° C., 66.97 g of isobutylene were passed dropwise through the gas inlet tube into the col- (0.671 g-mol) 98.27% sulfuric acid in the course of 30 minutes. The remaining hydrogen cyanide was added in 30 minutes at 0 ° C. After the addition of half an hour was added and 28 g of sulfuric acid had been completed, the reaction (0.5 mol) isobutylene was mixed in 60 minutes in a 1 hour water bath, which absorbed the action mixture. The reaction mixture was kept 70 ° C, heated. The homogeneous reaction was then heated to 60 to 65 ° C, the mixture was left to stand for 40 hours at room temperature overnight and then poured onto ice, with a lid, after which the mixture crystallized out. The micentrated ammonia was neutralized and four times with schung was cooled in an ice bath while ether extracted. The ethereal solution was ^{dried over 100 cm 3 of} water dropwise in 15 minutes to anhydrous sodium carbonate, and the were set. No diisobutylene separated from the residue after removal of the ether (a clear solution was obtained). Distilled at fortified vacuum. 47.5 g were obtained (94% of the ice cooling set was a total of 117.7 cm ³ Am theory) of N-tertiary butylformamide; Bp. ₁₈ = 95 to monia solution (29%) added, the pH being 1505 ° C). was brought to over 10. Even after adding

For example 2 ^ 2 ammonium sulfate, no oil separated. the

aqueous mixture was poured into a 11-capacity

The dilution of 204 g of 96% strength sulfur separating funnel and transferred four times with acid each time with 35.2 g of water resulted in 2 mol of 82% strength acid. 100 cm ^{3 of} ether extracted. The combined ether extracts from this sulfuric acid, which contained 18% water, were dried over 20 g of anhydrous potassium carbonate, approximately the fourth portion of 44 cm ³ (1.14 mol) of carbonate. The dried ethereal solution of liquid hydrogen cyanide at 20 to 25 ° C was placed in a 17 cm high and one diameter device of Example 1, and then 50 of 2.5 cm reflux ratio of was started with the introduction of isobutylene. Fractionated 3: 1 until vapor began to escape. The rest of the hydrogen cyanide was in this (very little liquid remained in the bladder). The temperature within 45 minutes and the iso- yellow remaining liquid, 4.1 g, _{boiling point 732} butylene (56 g = 1 mol) within a period = 194 ° C (corrected), η ^a ₀ ° = 1.4355, added completely within 90 minutes. The reaction mixture 55, which was miscible with water, was found to be almost pure and was heated to 60 to 65 ° C. and then N-tert-butylformamide overnight.

N-tertiary butylformamide formed 4.1 g

Formed diisobutylene -

Yield of N-tert-butylformamide (based on the 41 χ
used isobutylene) · t- ^ tj = 7.57% of theory.

The selection of the reaction conditions according to the invention therefore makes it possible to achieve an essential to achieve a higher yield of N-tertiary-butylformamide.

The N-tertiary-butylformamide is used in many ways, including in the production of N-tertiary-butyl-2-benzothiazolesulfenamide and, since it is liquid at high temperature, as a solvent for other organic compounds.

Claims (2)

Patent claims: 1. Process for the preparation of N-tertiary-butylformamide by reacting about 1 mole Isobutylene with about 1 mol of hydrogen cyanide in the presence of sulfuric acid and neutralize of the acidic reaction mixture, characterized in that that the isobutylene at a temperature of 20 to 25 ° C gradually the sulfuric acid, the 13 to 18% water and contains part of the required amount of hydrogen cyanide, then adds the remaining amount of hydrogen cyanide at the same time as the isobutylene is gradually added to the acidic mixture, then the reaction mixture heated to about 60 to 65 ° C and the hydrogen cyanide in introduces molar excess at a greater rate than the isobutylene into the acidic solution and the molar ratio of isobutylene to sulfuric acid is 1: 1.5 to 1: 2.5. 2. The method according to claim 1, characterized in that the reaction mixture neutralized with an aqueous ammonia solution. Considered publications:
German Patent Nos. 870 856, 872789; U.S. Patent No. 2632023.