DE1270045B - Process for the preparation of mixtures of primary, secondary and tertiary methylamine - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

German class:

Number:
File number:
Registration date:
Display day:

C07c

BOIj
COIc

12q-3

12 ο-1/01; 12 g-11/78;

12 g-11/80; 12 k-1/02

P 12 70 045.7-42
November 22, 1963
June 12, 1968

According to a known process for the preparation of methylamines, hydrogen cyanide is produced according to the following Hydrogenated reaction scheme:

HCN + 2H ₂ -

2 HCN + 4 Η,

3 HCN + 6H ₂

► CH ₃ - NH ₂

► (CHs) ₂ NH + NH ₃

► (CHs) ₃ N + 2 NH ₃

However, the transfer of the process to the industrial scale appeared for the following reasons impossible: In the hydrogenation of hydrogen cyanide ^ side reactions can become predominant, whereby a polymerization of hydrocyanic acid with the formation of little known solid products and hydrogenolysis of the hydrocyanic acid to methane and ammonia according to the reaction

HCN + 3 H ₂ ■

-CH ₄ + NH ₃

can enter. The hydrogen cyanide often shows up as a contact poison when using reduction catalysts such as copper, nickel and cobalt.

There has now been a method of making mixtures of primary, secondary and tertiary Methylamine by catalytic hydrogenation of hydrogen cyanide in the gas phase at one temperature between 80 and 250 ° C. and an excess of hydrogen in the presence of a hydrogenation catalyst found, which is characterized in that the hydrogenation at a molar ratio of Hydrogen to hydrogen cyanide from 5 to 30: 1 at a pressure of up to 15 at and in the presence of 0.5 to 10% of a platinum metal on a support of diatomaceous earth and kaolin in a weight ratio of 1: 1.1 to 10 performs.

The above-mentioned disadvantages are avoided by the method according to the invention. The active metal content of the catalyst is usually about 5% and the hydrogenation is usually carried out at about 8 atmospheres. The molar ratio of hydrogen to hydrogen cyanide is generally from 15 to 20: 1, and the process is usually carried out between 100 and 200 ⁰ C. The hydrogen cyanide must not contain any impurities such as sulfur, phosphorus or arsenic.

The process according to the invention enables the hydrogenation of cyanogen hydrogen in the gas phase with high yields under economical conditions and with simple equipment. That The process has the advantage that hydrogen cyanide and hydrogen are used in proportions the technical utilization of the endothermic synthesis of hydrogen cyanide from methane and ammonia resulting mixture of cyan

Process for the preparation of mixtures from
primary, secondary and tertiary methylamine

Applicant:

Societe d'Electro-Chimie, d'Electro-Metallurgie

et des Acieries Electriques dlUgine, Paris

Representative:

Dipl.-Chem. Dr. HG Eggert, patent attorney,
5000 Cologne-Lindenthal, Peter-Kintgen-Str. 2

Named as inventor:

Paul Besson,

Pierre Thirion, La Chambre, Savoie (France)

Claimed priority:

France of November 24, 1962 (916 494)

make hydrogen and hydrogen possible. The synthesis of methylamines can thus be done with this synthesis combined and carried out using methane and ammonia as starting materials will.

If palladium is used as the catalyst metal, the catalyst can be prepared, for example, as follows: At a temperature of about 70 ° C., palladium chloride (Pd CI2) is introduced into an aqueous, dilute hydrochloric acid solution. The homogeneous solution obtained is mixed with ammonia in 28% strength aqueous solution until the precipitate initially formed has completely dissolved. In this way, an aqueous, homogeneous solution of palladium dichloramine, Pd (NHs) ₂ Cl ₂ , is obtained. Such an amount of diatomaceous earth is added to this solution that a thick and smooth paste is obtained. This pulp is dried at a temperature of 150 ^° C., ^{kept at 350 °} C. for 3 hours and finally finely comminuted and sieved. Kaolin is added to the powder obtained, and such an amount of water is gradually kneaded into the mixture that a dry paste is obtained which is shaped into grains of thread with the aid of a press. The shaped catalyst is ^{dried at 150 °} C. and then held at a temperature of about 350 ° C. for 1 to 3 hours.

After this treatment, the very strong grain of thread obtained becomes one in a closed space thermal treatment at a temperature between

809 559 537

see subjected to 300 and 500 ° C in a chlorine atmosphere. This thermal treatment enables a very strong improvement in the activity of the catalyst.

The catalyst produced in this way can now be used in the process. He will used for this purpose in the catalytic furnace, where it is before the hydrogenation of the hydrogen cyanide ;? at a Temperature between 100 and 200'C, usually between 120 and 150 "C, reduced with hydrogen will.

After a certain running time, the catalyst has to be as a result of more or less strong deposits be regenerated. This regeneration can be carried out as follows: In a first stage air and steam are passed over the catalyst in precisely set proportions from 50 to 100 liters of air and 0.25 to 30 kg of water vapor per hour per liter of catalyst. This treatment is carried out at a temperature of about 400 to 450 C until the gas escaping from the furnace practically no longer contains carbonic acid.

In a second stage, in which the temperature is kept at the same level, the air is replaced and water vapor from chlorine. This second treatment takes about 1 hour. After a reduction with hydrogen at a temperature of about 120 to 150'C, the catalyst can again for the Production of methylamines are used.

A palladium catalyst suitable for the process according to the invention was prepared as follows been:

. At a temperature of about 70 ° C., 40.6 g of palladium chloride (PdCl-i) are dissolved in 250 cm ^{3 of} an aqueous hydrochloric acid which contains 90 cm ^{3 of} aqueous, concentrated hydrochloric acid with a density of 1.19. After dissolution and cooling, 140 cm ^{3 of} 28% ammonia are slowly added with stirring. The heterogeneous solution obtained is brought to the boil until the precipitate formed has completely dissolved.

Then slowly 480 g are added to the aqueous, homogeneous solution of the palladium dichloramine Kneaded in diatomaceous earth. The paste obtained was dried at 150 "C and then for 2 hours subjected to a thermal treatment at 350.degree. The solid mass obtained is crushed and sieved on a 74 micron mesh sieve. After dry mixing with 170 g of kaolin, the mixture is kneaded with water in such an amount that a plastic, little moist paste is obtained.

This paste is shaped with a thread press, which is provided with a perforated disk, the holes in it have a diameter of 5 mm. The grain of thread produced in this way is dried at 150.degree and then a thermal treatment for 2 hours at a temperature of about Subject to 350 C. The catalyst prepared in this way becomes a thermal for about 1 hour Subjected to treatment at a temperature of 400 to 450 C in the presence of chlorine.

The catalyst, which is ready for use in the process, had the following composition: palladium (in the form of the chloride PdCk) 4.2 " _and carrier 95.8 ¹ vol. The catalyst prepared in the manner described was used for the experiments described below of methylamines used by the method according to the invention.

example 1

The palladium catalyst was used in an amount of 1 1 in a device consisting of a Stainless steel pipe with a length of 1.4 m and a diameter of 3 cm. the The device was brought to a temperature of 150 ° C. and the catalyst with it for about 1 hour Hydrogen reduced. After the reduction, the temperature of the device was increased to 185.degree brought.

Then, hydrogen in an amount of 160 mol per hour, corresponding to 36001, was calculated at 0 C and 760 mm Hg, and hydrogen cyanide in an amount of 8.78 mol per hour accordingly 237 g passed over the catalyst. The molar ratio of hydrogen to hydrogen cyanide was thus 18.2. The pressure in the device was kept at 8 atm. The following results were received:

Total conversion of hydrogen cyanide 100 "ή Yield of monomethylamine ... 14.2%

Yield of dimethylamine 17.5%

Trimethylamine yield 57.5 "»

Total yield of methylamines 89.2 "η Methane formation 9.5 "»

The following amounts of methane, ammonia and methylamine were formed every hour:

Methane 13.3 g

Ammonia 86.3 g

Monomethylamine 38.7 g

Dimethylamine 34.6 g

Trimethylamine 99.1 g

Example 2

After a running time of a few hours, the following reaction conditions were used: without any treatment to reactivate the catalyst having been carried out:

Temperature 185 C

Absolute pressure .. 8 atm

Amount of hydrogen .. 240 mole hours .. corresponding to about 5400 1, calculated at 0 C and 760 mm Hg

Hydrogen cyanide

menee 18.4MoI hours, accordingly

497 g

The molar ratio of hydrogen to hydrogen cyanide was thus 13.
The following results were obtained:

Total conversion of hydrogen cyanide K) O ¹¹ D Yield of monomethylamine ... 20.2 " ₍ >

Yield of dimethylamine 18.4 "»

Yield of trimethylamine 40.5 "0

Total yield of methylamines 79.1% methane formation "18.3" "

The following amounts of methane were added every hour. Ammonia and methylamines formed:

Methane 54 g

Ammonia 179 g

Monomethylamine 115.5 g

Dimethylamine 76.3 g

Trimethylamine 146.4 g

Example 3

Without prior reactivation of the catalyst, a new reaction for the hydrogenation of hydrogen cyanide was carried out under the following conditions

Temperature 185 C

Absolute pressure '''3 atm hydrogen quantity'. ". 160 mol / hour .. corresponding to t. I & m ι Vi t K ^-

Oc and 760 mm Hg

amount 8.95 mol / hour, accordingly

The molar ratio of hydrogen to hydrogen cyanide was thus 17.9.

The following results were obtained:

Total conversion of hydrogen cyanide 100 "(i

Yield of monomethylamine .. 54.8 "»

Yield of dimethylamine 16.1 "»

Yield of trimethylamine 16.7 " ₍ >

Total yield of methylamines 87.6 ""

Methane formation 9.6 " ₍₎

The following amounts of methane were added every hour. Ammonia and methylamines formed:

Methane 15.35 g

Ammonia 48.10 g

Monomethylamine 151.70 2

Dimethylamine 32.50 g

Trimethylamine 29.40 g

After the catalyst was regenerated in the manner described above, the catalyst could be used again for the hydrogenation of hydrogen cyanide.

Claims (2)

Patent claims: '■ Process ^{for the} preparation of mixtures ^{of primary} ' secondary and tertiary methyl ^{amine d} ^. ^k atalytische hydrogenation of hydrogen cyanide in the gas phase at a temperature ^such J ^{ic "8} _ff ^° ™>^{C" n} f an excess of hydrogen in the presence of a Hydnerungskatalysators, characterized in that the hydrogenation is at an MOI ratio of hydrogen to hydrogen cyanide from 5 to 30: 1 at a pressure of up to 15 atm and in the presence of 0.5 to 10% of a platinum metal on a support made of diatomaceous earth and kaolin in a weight ratio of 1: 1.1 to 10. 2. The method according to claim 1, characterized in that there is a weight ratio of diatomaceous earth used to kaolin from 2.5 to 3. 3. The method according to claim 1 or 2, characterized in that the catalyst with 5 to 50, in particular 10 to 20 mol of hydrogen cyanide per hour and liter of catalyst are loaded. Considered publications:
Beilstein, Handbook of Organic Chemistry. 4th edition, Hauptwerk Vol. 2, p. 36; I. Supplementary work, Vol. 2. p. 24; Journal of the Chemical Society, 115, pp. 902-907 (1919). 809 559/537 5, 68 © Bimdesdruckerei Berlin