DE1468774B - Process for the production of monoalkyl- or -cycloalkyl-ureas - Google Patents

Description

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The invention relates to a process for the preparation usually at about 0.05 moles of NH ₃ per mole of ketone,

of mono-alkyl or -cycloalkyl ureas. Preferably 0.1 to 0.3 moles of ammonia each

Process for reducing alkylation of Ke- Mol ketone added.

Clays with urea and hydrogen in the presence The process is carried out at elevated temperatures and a hydrogenation catalyst are known. So far 5 presses carried out. Temperatures from 80 to this method for the production of mono 200 ⁰ C are well suited; Excellent results from alkyl ureas with relatively short alkyl ureas are obtained at about 100 to 145 ° C. The hydrogen groups, such as mono-isopropyl urea, refer to pressure can be about 35 to 281 atmospheres, especially (cf. US Pat. No. 2,477 872), but if they give good results, only very low yields are obtained with hydrogen pressures. High yields could be from 70 to 141 atm.

According to this process so far only in the catalytic The process only requires reaction times in the hydrogenating conversion of urea with long-order of 1 to 30 minutes, but chain ketones, such as stearone or palmitone, can also be achieved in reaction times of 100 minutes (German Patent 946,984). Attempts to carry out putting. With reaction times of more such processes and carrying out the alkylation 15 than 3 hours, larger amounts of improved in the presence of ammonia are easily formed (USA.- undesirable by-products, especially in Di-Patent 2,673,859) led to the formation of large alkylureas. At ReMengen it is preferred to work on undesired by-products and reaction times of 1 to 60 minutes,
demanded very long response times in many cases. As hydrogenation catalysts, metals such as

It has now been found a combination of working conditions nickel, iron, cobalt and copper, platinum, palladium, under which urea with ruthenium, rhodium and / or osmium, in a finely selected group of ketones in good condition or on carriers such as aluminum yield without forming or only low oxide, silica, activated carbon or diatomaceous earth, comparable β formation of undesirable byproducts in short be spent. Particularly suitable catalysts for reaction times to the correspondingly substituted 25 are the oxides, suboxides, sulfides and subsulfides which ureas can convert. the above metals as well as tungsten, molybdenum

This process for the production of mono-alkyl and cerium containing zirconium, thorium,

or cycloalkyl ureas of the general formula silicon dioxide or aluminum as promoter. Also

Mixtures of several of these metal oxides, suboxides,

jj 30 -sulfides or -subsulfides or mixtures of metal-

' ^! oxides, suboxides, sulfides or subsulfides with

R - NH - C - NH ₂ metals are used as catalysts and components

of catalyst mixtures supported or unsupported

wherein R is a C ₃ - to C ₉ -alkyl radical or a cyclo- suitable.

aliphatic radical with 5 or 6 ring carbon atoms, 35 Preferably promoter-containing nickel or

the optionally a C ₁ - to C ₃ -alkyl radical carry cobalt catalysts, in particular on a 1 to

can, means, by reacting urea with 5% zirconium-containing carrier made of kieselguhr,

a corresponding ketone and hydrogen in counter-used. These catalysts are commercially available

wart of ammonia and a hydrogenation catalyst and can be easily obtained in a known manner

Activate the sator at higher pressures and temperatures is 40 by adding a small amount of water,

according to the invention characterized in that the hydrogenation catalyst is usually in

the conversion at molar ratios of ammonia amounts of less than about 20 percent by weight,

to ketone from 0.05: 1 to 0.5: 1. preferably less than 10 percent by weight, des

The method according to the invention is applied to ketones. Catalyst amounts of approx.

especially in that in the absence of 45 1 to 5 percent by weight of the ketone is usually supplied- *>!

can be carried out by solvents. satisfactory results.

As ketones in the context of the invention, for. B. It has been shown that the type of catalyst

Acetone, methyl ethyl ketone, diethyl ketone, methyl additive can affect the yield. When

propyl ketone, diisopropyl ketone, n-propyl-n-butyl ketone, the catalyst in the reaction mixture at the

Methyl isobutyl ketone, diisobutyl ketone, methyl iso-50 ambient temperature slurried and the

amyl ketone, ethyl butyl ketone, ethyl amyl ketone, mixture under hydrogen pressure on the reaction

ethylhexyl ketone, cyclopentanone, cyclohexanone, heated to temperature, are already high yields

3-n-propyl-cyclopentanone, 3-methyl-cyclohexanone achieved. Surprisingly, you get even higher ones

and 2-ethyl-cyclohexanone can be used. Yields if the catalyst is first added

The urea and ketone can in about 55 after the urea, ketone and ammonia

equimolar amounts, but also something from it - in the presence of hydrogen to the desired

varying amounts are used. For example temperature has been heated,

you can relate 1 mole of ketone with about 0.5 to 1.5 moles of urine in the following examples, if

implement material. nothing else is indicated, partial and percentage

The ammonia allowed in the invention 60 gave on the weight and the yields on the

Process in amounts of not more than about 0.5 mol of urea used,

can be used per mole of ketone. Amounts of ammonia. .

Above this maximum value lead to severe deterioration

Reduced yield and increased formation. A stainless steel hydrogenation autoclave from

of by-products, such as alkylamines, alkanol 65 400 cm ³ capacity, which with an elec-

derivatives and dialkylureas, and make longer tric heating mantle and a shaker

Response times necessary. The lower limit of the is equipped with a mixture of 1 mole

The amount of ammonia is not so important, but it is (60 g) urea, 1 mole (72 g) methyl ethyl ketone,

2.5 g of a promoter containing 50% nickel and 2% zirconium on kieselguhr containing catalyst and 0.294 moles (5 g) of liquid ammonia were charged. It releases hydrogen to and the mixture heated for 1 hour at a total pressure of 105 at at 125-140 ⁰ C, the reaction mixture cools, it carries from the Atuoklav out, it is dissolved in 100 cm ³ of water, the catalyst is filtered off, leaves the The filtrate cools and gains two crystal yields by filtration. A third crop of crystals is obtained by adding potassium chloride to the remaining filtrate. The solid product is examined by melting point determination, ultrared analysis and gas chromatography. The melting point of the crude products is 148-163 ⁰ C, and the Ultrarotanalyse shows the presence of sec-butylurea and a trace of di-sec-butylurea. On the basis of the quantitative gas chromatographic analysis, a total of 89.5 g of sec-butylurea and 4.3 g of di-sec-butylurea were formed. The yield of sec-butylurea is 77%

Example 2

Example 1 is carried out with the modification that 3 g of a 50% cobalt and 2% zirconium oxide used on kieselguhr containing catalyst. Doing so will be similarly satisfactory Results achieved.

Example 3

Using the device and the catalyst according to Example 1, the autoclave is charged with 60 g (1 mol) of urea, 5 g of catalyst, 72 g (1 mol) of methyl ethyl ketone and 1.7 g (0.1 mol) of ammonia and the reaction occurs carried out a hydrogen pressure of 98 atü. After 30 minutes of reaction at 130 ^° C., an amount of hydrogen corresponding to 63 atm has been absorbed. The reaction mixture (137 g) is discharged from the autoclave, the solids are dissolved in 100 cm ^{3 of} hot water and the catalyst is filtered off. On cooling and concentration, the filtrate gives two crystal yields totaling 102 g, analysis of which shows 81.6 g of sec-butylurea, 7.5 g of di-sec-butylurea and 13 g of unreacted urea. The melting point of the crude products is 152-165 ⁰ C and the yield of sec-butylurea 70.5 ° / _0th

Example 4

Example 3 is carried out with the modification that the same molar amount of diisopropyl ketone is used in place of the methyl ethyl ketone. Man receives l-isopropyl-2-methyl-n-propylurea in excellent Yield.

Example 5

Using the apparatus of Example 1 charged to the autoclave with 60 g (1 mole) of urea, 5 g of a 5% ruthenium and 95% aluminum oxide existing catalyst and 8.5 g (0,50MoI) ammonia, heated to 80 ⁰ C. and presses hydrogen up to a pressure of 70 atü. A 250 cm ³ stainless steel pressure vessel, which is connected to the autoclave via a valve, is charged with 85 g (1 mole) of acetone to which a trace (1 cm ³ ) of water has been added. Using a hydrogen pressure of approximately 77 to 98 atmospheres, the acetone is injected into the autoclave in five portions over the course of 30 minutes from the pressure vessel. The autoclave pressure rises gradually from 35 to 98 atm and the temperature from 80 to 109 ^° C. The contents of the autoclave are then ^{heated to 120 °} C. and kept at this temperature for 30 minutes under a hydrogen pressure of 98 to 112 atm.

After rapid cooling to room temperature, the solid reaction mass is dissolved in acetone to remove the To be able to filter off the catalyst. The acetone filtrate is concentrated to almost dryness in vacuo

ίο and isolated 80 g of solid (melting point = 100 to 108 ⁰ C) by filtering and drying. The quantitative gas chromatographic analysis shows that the solid consists of 64% isopropylurea (51.2 g) and the remainder of diisopropylurea and unreacted urea. Recrystallization of the crude product from water gives a ^{solid substance which melts at 134 to 138 °} C. and which is found to be isopropylurea in the ultra-red analysis. The yield is 50%.

Example 6

Using the device according to Example 1, the autoclave is charged with 60 g (1 mol) of urea, 98 g (1 mol) of cyclohexanone, 2.5 g of catalyst according to Example 2, 5 g (0.294 mol) of ammonia and 1 g of water and pressed at room temperature hydrogen up to a pressure of 98 atm. After heating to 135 ^° C. for 40 minutes, the hydrogen pressure being kept at 98 to 112 atmospheres, the reaction mixture is cooled, the excess pressure is released from the autoclave, the reaction mixture, 140 g of gray solid, is released and it is dissolved in 400 g cm ^{3 of} methanol, the catalyst is filtered off, the clear filtrate is allowed to cool and several crystal yields are obtained. The first two, low crystal yields consist mainly of Ν, Ν'-dicyclohexylurea. The main yield of 100 g turns out on analysis to be crude cyclohexylurea (crude yield 70%) · If one takes a fraction of the main product out

Recrystallized ethyl alcohol, pure cyclohexylurea is obtained; Fp. = 202 to 203 ⁰ C.

Example 7

Example 6 is carried out with the modification that 15 g of Raney nickel are used as the catalyst. Similar satisfactory results are obtained.

Example 8

Example 6 is carried out with the modification that the same is used in place of the cyclohexanone molar amount of cyclopentanone used. An excellent yield of cyclopentylurea is obtained.

B e i s ρ i e 1 9

Example 6 is carried out with the modification,

that the same molar amount of 3-methyl-cyclohexanone is used in place of the cyclohexanone.

This results in an excellent yield of 3-methylcyclohexyl urea receive.

Example 10

A 1000 cm ³ stirred autoclave made of stainless steel is treated with a suspension of 180 g (3 mol) of urea in 27 cm ^{3 of} water, 216 g (3 mol) of methyl ethyl ketone, 8 g of one made from 5% ruthenium, 1% aluminum oxide and 94% Silica existing catalyst and 15 g (0.885 mol) of ammonia charged and the

Reaction carried out at a hydrogen pressure of 70 atm. After one hour of reaction at 100 to 112 ° C., an amount of hydrogen corresponding to 77 atm has been absorbed, whereupon the reaction mixture is cooled to 25 ° C., ^{diluted with 200 cm 3 of} water and the material is discharged from the autoclave. 415 g of the 750 g obtained are worked up, and after the catalyst has been filtered off, the clear filtrate is allowed to cool. 163 g of solids (melting point = 146 to 162 ° C.) are obtained from the filtrate and are analyzed. This product section contains 127 g of sec-butylurea and 24.8 g of N, N'-di-sec-butylurea. The total yield of sec-butylurea is therefore 65.8%.

Example 11

Using the device and the catalyst according to Example 1, the autoclave is charged with 60 g (1 mol) of urea, 72 g (1 mol) of methyl ethyl ketone, 5 g (0.294 mol) of ammonia, 1 cm ^{3 of} water and 5 g of catalyst, and hydrogen is used and heated the autoclave contents for 15 minutes at a hydrogen pressure of 98-105 atmospheres to 120-145 ° C. After cooling, the reaction mixture (136 g) is discharged from the autoclave, dissolved in 300 cm ^{3 of} ethyl alcohol, the catalyst is filtered off, the clear , concentrated alcoholic filtrate in vacuo to almost dryness and the residue was ^{recrystallized from 400 cm 3 of} water. The clear, hot aqueous solution is saturated with potassium chloride, the absence of di-sec-butylurea being evident from the fact that no oil phase separates out of the hot aqueous salt solution. The aqueous salt solution is cooled to room temperature and two crops of crystals are obtained by filtration. The first product yield (71 g) contains 2.4% of potassium chloride, and melts at 160 to 165 ° C, while the low, second crop of crystals (mp. = 168-170 ⁰ C) is 0.4 g. Both crystal yields turn out to be sec-butylurea in the infrared analysis. The yield of sec-butylurea is 60%.

Example 12

Example 11 is carried out with the modification that 12 g of a catalyst composed of 47% nickel, 2% zirconium oxide and 51% kieselguhr and the same molar amount in place of methyl ethyl ketone Methyl isobutyl ketone is used. This gives 1,2,2-trimethyl-n-propylurea in excellent form Yield.

Example 13

A reaction device, which is kept under a hydrogen pressure of 70 to 211 atm at 100 to 160 ⁰ C, continuously molten urea of 135 ° C, a 25 to 75 ° C warm slurry of 3% of the catalyst according to Example 1 in methyl ethyl ketone with stirring and liquid ammonia fed in three separate streams at such rates that the feed molar ratio of urea to methyl ethyl ketone to ammonia remains constant at a value of 1: 1: 0.240. The mean residence time of the reactants is 15 to 18 minutes. The reaction product is continuously withdrawn from the reaction device via a pressure reducing valve into a stirred tank, to which sufficient water is continuously added that a 40 to 60 percent solution of the product is formed. The unreacted methyl ethyl ketone is distilled off from the solution continuously withdrawn from the stirred tank in a 2-tray column. The azeotropic mixture of 89% methyl ethyl ketone and 11% water, which ^{boils at 73 to 74 0} C, is collected at the top of the column and returned to the second feed stream in the amount required in each case. The suspended catalyst is removed from the hot product solution flowing off from the column bottom in a filter press and, after partial reduction with hydrogen, is returned to the second feed stream in the required amount. The water is removed from the filtered product solution in a drum dryer. The dried product proves analytically to be sec-butylurea, which is contaminated with only minor amounts of N, N'-di-sec-butylurea, urea and water, and is obtained in excellent yield.

Example 14

The device according to Example 1 is charged with a mixture of 60 g (1 mol) of urea, 5 g of catalyst according to Example 1, 72 g (1 mol) of methyl ethyl ketone and 8.5 g (0.5 mol) of ammonia. As soon as the reaction mixture ^{has reached a temperature of 140 °} C. after rapid heating, the initial hydrogen pressure is increased from 211 to 281 atm. After a residence time of 10 minutes at 140 to 150 ^° C., an amount of hydrogen corresponding to 74 atm has been absorbed. The reaction mixture is now rapidly ^{cooled to 100 °} C. and poured into 100 cm ^{3 of} water and the catalyst is filtered off from the hot solution.

After adding sodium chloride, 85 g of solids (melting point = 157 to 165 ° C.), 92% of which are obtained, are obtained sec-butylurea, 5% from N, N'-di-sec-butylurea and 3% from unreacted urea exist. The yield of pure sec-butylurea is 67.5%.

Example 15

The autoclave of Example 1 is charged with a mixture of 90 g (1.5 mol) of urea, 72 g (1 mol) of methyl ethyl ketone, 5 g of the cobalt catalyst according to Example 2, 1 cm ^{3 of} water and 8.5 g (0.5 mol) of ammonia, and heated at an initial hydrogen pressure of 35 atm rapidly to 200 ° C. the hydrogen absorption starts at 100 ⁰ C, and the reaction mixture is maintained atü 20 minutes 200 ⁰ C and a pressure of 35th After cooling to room temperature, the pressure is released, 150 cm ^{3 of} water are added to the reaction mixture and the clear solution obtained is concentrated to dryness in vacuo.

The dry crude product, the weight of which is 105 g, consists of 47% sec-butylurea 15% from N, N'-di-sec-butylurea and 38% from unreacted urea. The yield at sec-butylurea is 42%, based on the methyl ethyl ketone.

At game 1 16

The autoclave of Example 1 is charged with a mixture of 30 g (0.5 mol) of urea, 72 g (1 mol) of methyl ethyl ketone, 2.5 g of the catalyst according to Example 1, 2 cm ^{3 of} water and 1.7 g (0 , 1 mol) ammonia, presses hydrogen at 25 ⁰ C up to a pressure of 105 atü and heats the reaction

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mixture 45 minutes to 100 to 105 ⁰ C. After absorption of an amount of hydrogen in a heated pressure reaction tube, which corresponds to a hydrogen 110 to 140 ° C, which corresponds to a total pressure of 35 at, the cooler, a Compressor and a circulation system reaction mixture is cooled and ^{equipped in 100 cm 3 of} water. One leads the tower continuously solved. Using a 2-tray distillation 5 a hot process stream of urea, methyl column, in the temperature range from 45 to ethyl ketone and ammonia in a molar ratio of 96 ° C 36 g of a distillate are collected, 80% of which is 1: 1: 0 , 2 and brings it together in the catalyst layer methyl ethyl ketone, 5% sec-butyl alcohol and 5 minutes with hydrogen at 141 atmospheres, the remainder consists of water and ammonia. The reaction product (sec-butylurea) is filtered off the catalyst from the residue in the bottom of the reaction device by means of a pressure distillation device and the filtrate is drawn off with a reducing valve arrangement and a Schup potassium chloride. The pen dryer fed from the filtrate as it cools. Unreacted methyl precipitate is filtered off and dried ethyl ketone, ammonia and excess water. The dried solids (melting point = 145 to 155 ° C.) are drawn off overhead through the cooler, consist of 33.5 g of sec-butylurea, 23.0 g of N, N'-di-15 and recompressed and in the circuit guided. When the sec-butylurea and traces of urea. The catalyst activity drops if the streams are switched on. The yield of sec-butylurea is 58%. of hydrogen and reactants from and

passes through the tower under high pressure

Example 17 Steam to completely remove the catalyst

20 product to clean. After the steam treatment

If desired, the catalyst can be charged in a semi-continuous process

is provided with a steam jacket, 2.8 1 fassen- two-hour reduction with hydrogen at 350 ⁰ C

re-condition the stirred autoclave with 510 g (8.5 mol) of urea. Then the catalyst

612 g (8.5 mol) of methyl ethyl ketone, 20 g of the in the by-layer cooled to 110 to 140 ° C and the operation

game 1 catalyst used and 41.5 g (2.44 mol) 25 taken up again. This results in high yields

Ammonia and heated in 5 minutes to 100 to 130 ° C. achieved in sec-butylurea.
A second, provided with a steam jacket,
3.81 capacity stirred autoclave, the one with the first

Autoclave (charging autoclave) via one of B e i s ο i e 1 19

Outside heated by a steam coil over 3 °
is connected to 110 to 120 ° C

heated. Using the arrangement of three cars, a hydrogen pressure of 14 to 70 atm is then set in the first autoclave, around the hot clave according to Example 17, the mixing autoclave with the reaction mixture is rapidly added to the second autoclave to 510 g (8.5 mol) of urea, 612 g (8.5 mol) of methyl transfer, and increases the hydrogen pressure in the ethyl ketone, 41.5 g (2.54 mol) of ammonia and a second autoclave immediately after the transfer of the slurry of 21.3 g of catalyst according to Bei-Gutes charged a constant value of 105 to 127 at. game 1 in 45 ml of water. The Austrageauto-Man the reaction mixture is 30 to 60 minutes klav containing 1500 ml of water, is heated to 100 ⁰ C to 115 to 12O ⁰ C, until the hydrogen absorption under. The hot reaction autoclave presses hydrogen into the mixing autoclave and the reaction pressure drops to 0.21 atmospheres per minute, and hydrogen is then introduced into a third 18 atm. The mixture is heated from urine autoclave 1500 ml of water from 60 to 8O ⁰ C contains, cloth, methyl ethyl ketone, ammonia and hydrogen, and contributes to pressure relief, the hot reaction at 120 to 125 ° C and transferred to it at this Tempe product of the Third autoclave into the distillation temperature under additional hydrogen pressure through a bubble of a two-tray distillation column 45 heated from the outside by means of a steam coil. With heating at a head temperature of high-pressure line into the reaction apparatus, the 100 ° C 200 g of distillate the main catalyst, water and hydrogen at from 95 to 100 ⁰ C are collected, contains plural of the azeotropic mixture of non-converted. When the transfer of the product is complete, the methyl ethyl ketone, water and ammonia are increased, the hydrogen pressure in the reaction autoclave and traces of sec-butyl alcohol and sec-butylamine 50 are increased to 105 to 127 atm. The hydrogen absorption persists. There are 90 g (1.25 mol) of unreacted begins immediately. After a reaction time of 45 to 60 minutes, methyl ethyl ketone is recovered and the hot reaction can be recycled to the process at 115 to 120 ° C. in a circuit. The mass obtained under full pressure into the discharge auto from the bottom of the still is hot and relieves the excess pressure; Product solution is recovered to remove the catalyst, 55 sec-butylamine, sec-butyl alcohol and not the other way around, regenerate and recirculate the methyl ethyl ketone that has been removed by distillation and can be recycled, passed through a filter. The catalyst is filtered off from the remaining hot aqueous and the filtered product solution with sodium chloride suspension, which is then added. On cooling and filtering, the filtrate is left to room temperature. 730 g of sec-butylurea and 30 g of di-sec-butylurea and the solid product is centrifuged off and dried material is obtained. The yield of sec-butylurea and analyzed. 94% of the product consists of 74%, based on the urea, or 86%> sec-butylurea, 4.5% of di-sec-butylurea, based on the methyl ethyl ketone. substance and 1% unreacted urea.

The mother liquor is mixed with common salt, whereby

If ρ ie 1 18 ⁶ 5 a small, second crystal yield is obtained. the

The total yield of sec-butylurea is 805 g

In a continuous process, the kata (81.8%) ^and that of di-sec-butylurea

lyser according to Example 1 in tablet form at rest - 55.7 g (5.6%) ■

Claims (1)

Claim: Process for the production of mono-alkyl or cycloalkyl ureas of the general formula R-NH-C-NH ₂ wherein R is a C ₃ - to C ₉ alkyl radical or a cyclo- 10 aliphatic radical with 5 or 6 ring carbon _{atoms, which can optionally carry a C 1} - to C ₃ -alkyl radical, means, by reacting urea with a corresponding ketone and hydrogen in the presence of ammonia and a hydrogenation catalyst at higher pressures and temperatures, that the reaction is carried out at molar ratios of ammonia to ketone of 0.05: 1 to 0.5: 1.