DE1220853B - Process for the preparation of the sodium or potassium salt of cyclohexylsulfamic acid - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
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C 07 c

German class: 12 ο - 25

1220 853
C34944IVb / 12o
January 25, 1965
July 14, 1966

The invention relates to a novel process for the preparation of the sodium or potassium salts of cyclohexylsulfamic acid.

The metal salts of N-cyclohexylsulfamic acid are known with metal hydroxide, sweet, without a bitter aftertaste, resistant to boiling and physiological harmless. So far, only those manufacturing processes have been of technical importance in which first from sulfamic acid and excess cyclohexylamine as starting substances the cyclohexylammonium salt of N-cyclohexylsulfamic acid and then from it by reaction with a metal hydroxide in the presence of water or with free Sodium metal is formed with the exclusion of water the corresponding metal salt.

In the first stage of this process, the starting substances mentioned in the presence of a inert solvent brought to reaction at elevated temperature. An excess can be used as a solvent of cyclohexylamine serve. The resulting cyclohexylammonium salt is usually separated by filtration or centrifugation from the reaction medium before it is in the second process stage converted into the metal salt. So far, one has been used for this transfer the various known methods given below.

One adds z. B. a slurry of the cyclohexylammonium salt in water with the appropriate amount of sodium hydroxide solution and then removed the released Cyclohexylamine by steam distillation, after evaporation also des Water the sodium cyclamate receives. One can use the cyclohexylammonium salt of N-cyclohexylsulfamic acid react with the aqueous sodium hydroxide solution in the presence of such solvents that a have good solvency for cyclohexylamine and are insoluble in water, such as Chloroform. In this process, the cyclohexylamine is removed by extraction with the second, water-insoluble solvent phase, which is then separated off. Receives here too one first an aqueous solution of the sodium cyclamate, which must be evaporated. Such procedures are z. B. in German patent specification 874 309 and in British patent specification 662 800 described. Their disadvantage is the high expenditure on equipment for working up the end product.

A simplification of the conversion of the cyclohexylammonium salt into the sodium salt eliminating these difficult and expensive processes for the preparation of the sodium or
Potassium salt of cyclohexylsulfamic acid

Applicant:

Heyden Chemical Factory

Aktiengesellschaft, Munich 23, Leopoldstr. 4th

Named as inventor:

Dipl.-Chem. Dr. Dezsö Peteri, Regensburg;

Dipl.-Chem. Dr. Otto Wiedemann, Munich;

Dipl.-Chem. Dr.-Ing. Reinhard Leitsmann,

regensburg

The purpose of working up is the process according to German Patent 1161 263, according to which the cyclohexylammonium-N-cyclohexylsulfamate reacted in the presence of an inert diluent at a temperature of 100 to 135 ° C with metallic sodium and then the reaction mixture is evaporated to dryness. For the removal of the Subsequent distillation is recommended for adhering cyclohexylamine. Working with metallic Sodium on a larger scale, however, requires special equipment and extensive precautionary measures.

It has now been found that the advantages of the implementation with metallic Sodium can be surprisingly beneficial without the associated disadvantages, if one the reaction with the alkali metal compounds indicated below in the presence of certain alcohols performs as a solubilizer.

The subject matter of the invention accordingly consists in a process for the preparation of the sodium or potassium salt of cyclohexylsulfamic acid by reacting cyclohexylsulfammonium-N-cyclohexylsulfamate with a compound of the corresponding alkali metal in the presence of an inert organic solvent, which is characterized in that the reaction with alcoholic sodium or potassium hydroxide or with a sodium or potassium alcoholate solution, C ₁ to C ₃ alcohols being used in each case.

609 589/349

With this treatment arises according to the reaction equation

NHSO ₃ A + H ₂ N- / eT)> + HOR

in addition to the desired end product only 1 mol. Particularly high yields are obtained if one

Cyclohexylamine and 1 mole of water or alcohol; the alkali alcoholates are used as alkali compounds.

A means sodium or KaÜum and R means hydrogen The almost quantitative ones obtainable in this way

or a low molecular weight alkyl radical with 1 to 10 yields are probably based on the fact that with

3 carbon atoms. - This implementation does not produce any water.

The equal practice that occurs in the solid phase is expediently worked in such a way that weight between the cyclohexylammonium-N-cyclo- that one is the cyclohexylammonium salt of the N-cyclohexylsulfamate and the alkali N-cyclohexylsulfamate, hexylsulfamic acid, with a solution or a liquid by adding the alcohol according to the invention, alkali hydroxide is suspended in the alcohol practically completely implemented to the side of the alkali salt. Alkali cyclamate falls as insoluble matter postponed. This fact makes it possible to remove the precipitate obtained, which is filtered off or centrifuged off Crude product after its isolation on the filter or becomes. The separated liquid contains in addition to in the centrifuge in the solid state amine-free to free cyclohexylamine the used to wash. The subsequent recrystallization from alcohol, water of reaction and small amounts of others Water already supplies impurities that meet the high requirements and are easily removed by distillation a product equivalent to a salable product. can be separated.

This easy cleaning possibility of the raw A preferred, particularly simple method The product is probably based on the fact that the one used to make the cyclo-reaction at relatively low temperatures the hexylammonium salt is the starting material with the stoichiometric amount of alkali setting of cyclohexylamine with sulfamic acid in hydroxide and, in a predominantly organic medium, excess cyclohexylamine under pressure goes, so that the formation of by-products leads, e.g. B. by heating under pressure to 160 bis is extremely low. With this transfer to 180 ° C for a period of 30 minutes to Alkali salts generally occur side reactions for 3 hours, with the ammonia being released through on which a relief valve is drained to form cyclohexylammonium sulfate. After that, will of the formula ■ the reaction mixture is cooled to about 50 to 60 ° C,

1 / ■. \ where part of the cyclohexylammonium formed

k "H y - NH ₃ J SO ₄ , crystallized from salt. If this reaction is now

^ 35 tion solution with the calculated amount of alkali

of the dicyclohexylaminosulfone of the formula hydroxydes in methanol or another suitable

/ Ν Neten alcohol and stirred for some time, there is the

NH - SO ₂ - NH - <i H \ solid bodies made of pure alkali cyclamate. After this

^ The alkali cyclamate can be cooled by filtering it

and sodium sulfate lead. The sodium sulfate can be isolated 4 ° or by centrifugation. The thereby received the desired end product through hydrolytic mother liquor, consisting of cyclohexylamine, The action of alkali metal hydroxide can lead to the formation of the alcohol used and the water of reaction Cyclohexylamine arise. It can be easily separated from the desired- by distillation, th end product but also through a dimerization. You can also do that with the described down Formation of Dicyclohexylaminsulfons arise. 45 position of the starting material through the implementation of the The dimerization product can be obtained from the desired sulfamic acid with excess cyclohexylamine th end product, however, also by the action of after the ammonia and the ab-cyclohexylamine have been split off Separate and separate the salt which has crystallized out with the formation of alkali hydroxide cooling, develop. In addition, it can be from the starting z. B. with sodium hydroxide in methanol, implement, material, the cyclohexylammonium salt of the N-Cyclo- 50 With this procedure, the excess Form hexylsulfamic acid by escaping water. For cyclohexylamine again for without further purification the suppression of these side reactions is the next approach to be used crucial that in the inventive A further variation consists in the fact that the the reaction times are short and the reaction temperatures produced as described above are fixed cyclic temperatures are low and that by the Aus 55 hexylammonium salt, for example with methanol and At the end of water, hydrolysis is largely offset by the calculated amount of sodium hydroxide is avoided. or that the entire reaction mixture from

Another major advantage of the excess of the invention. Cyclohexylamine and sulfamic acid according to the method consists in that it is continuous with solid alkali hydroxide and as a solution can be carried out as the alcohol chosen by the 60 intermediaries is added. At this The reaction between the sulfamic acid and the procedure must be finely divided Cyclohexylamine produced starting product not the slurried solid starting materials for the needs to be isolated and as the transfer implementation pay attention so that the individual particles do not of the cyclohexylammonium-N-cyclohexylsulfamate into alkali-N-cyclohexylsulfamate due to the insoluble end product also be closed in the presence of 65. It is therefore also for an intenmehr than 1 mole of cyclohexylamine can be carried out without careful stirring. The manufacture of the that as a result a substantial additional expenditure for the starting salt is not the subject of the protective removal the same arises. '. desire. .

The following examples are intended to explain the process in more detail.

example 1

_{970 g of amidosulfonic acid and 41 of cyclohexylamine (with a water content of less than 0.5 ° / 0} ) are introduced into a reaction vessel of about 15 l capacity, which is equipped with a stirrer, a reflux condenser with a relief valve, a manometer and a thermometer . The reaction mixture is heated to 160 to 165 ° C. with stirring, the ammonia formed being drained off with the aid of the expansion valve. After the reaction mixture is cooled to 5O ⁰ C, wears slowly added a solution of 400 g of sodium hydroxide in 41 methanol and the mixture is heated for 15 minutes at 65 to 7O ⁰ C. After cooling to 15 ° C is isolated, the crude sodium N-cyclohexyl sulfamate by centrifugation. The product is washed with methanol in portions of about 21 each until a sample has a cyclohexylamine content of less than 0.2%. As a rule, this requires a total of 51 methanol.

To obtain about 2150 g of crude product with a methanol content of from about 12 ° / _0th This corresponds to a yield of about 95 ° / ₀ of theory.

The crude product is dissolved in 3800 ml of water at 70 ⁰ C and treated with Klärkohle. After removal of the charcoal by filtration, allowed to crystallize out the solution at 1O ⁰ C. The crystals are filtered off with suction and dried. The mother liquor is used in the next batch to dissolve the crude product. The average yield of recrystallized pure finished product is about 90 ° / ₀ of theory.

The finished product has the following analytical indicators:

2 g of the sample dissolve in 10 ml of water, clear and colorless. The solution is free of any visible contamination. The pH of a 10 ° / ₀ solution is 6.8. The nitrogen content of the sample is 6,92 ° / o.

A l ° / ₀ solution of the sample remains clear after the addition of hydrochloric acid and barium chloride.

Example 2

In accordance with the procedure of Example 1, 970 g of sulfamic acid are reacted with 41 cyclohexylamine. The reaction mixture is mixed at 65 ° C with 400 g of finely powdered sodium hydroxide and 41 of methanol with vigorous stirring and maintaining a reaction temperature of 65 ⁰ C after cooling. The mixture is then kept at the boil for 30 minutes at the reflux temperature. The batch is then cooled to room temperature and suctioned off through a suction filter. After washing with about 31 methanol (with a water content of less than 0.5%) of about 2,200 g of crude product is obtained with a Cyclohexylamingehalt of 0.15 ° / ₀ and a methanol content of about 18%, an yield of about 90 ° / ₀ corresponds to the theory. After recrystallization from water in the manner described in Example 1, a sodium cyclohexylsulfamate whose analytical characteristics match those of Example 1 is obtained.

Example 3

280 g of cyclohexylammonium N-cyclohexylsulfamate are poured over a three-necked flask equipped with a stirrer, dropping funnel and reflux condenser with 11% ethanol (with a water content of less than 0.3 ° / ₀ ) and heated to about 70 ° C. At this temperature, a solution containing 65 g of potassium hydroxide dissolved in 500 ml of ethanol is added within about 1 hour. The batch is then refluxed for a period of 15 minutes. After cooling to room temperature the crystals are filtered off, washed with alcohol until reaching an amine content of about 0.15% and dried is obtained in this way 205 g Kaliumcyclamat, corresponding to a yield of 93.6% of theory at 5O ⁰ C. is equivalent to. The nitrogen content of the product is 6.4% (theoretical value: 6.39%).
If this example is carried out with a solution of the equivalent amount of potassium methylate in methanol, the same end product is obtained in almost quantitative yield.

Claims (1)

Claim: Process for the preparation of the sodium or potassium salt of cyclohexylsulfamic acid by reacting cyclohexylsulfammonium-N-cyclohexylsulfamate with a compound of the corresponding alkali metal in the presence of an inert organic solvent, characterized in that the reaction is carried out with alcoholic sodium or potassium hydroxide or with a sodium - or potassium _{alcoholate solution, with C 1} - to C ₃ -AlkO-hole being used in each case.