FI90763B - Process for synthesizing arylsulfonylalkylamides - Google Patents

Abstract

Process for the synthesis of arylsulphonylalkylamides in which an arylsulphonyl halide is placed in contact with an excess of alkylamine and an aqueous solution of alkaline agent in excess in relation to the arylsulphonyl halide and then the water and excess amine are removed from the organic phase; the arylsulphonylalkylamide is then isolated. This process is particularly suited for N-n-butylbenzenesulphonamide which is obtained in a thermally stable quality and which can be advantageously employed as a plasticiser for polyamides.

Description

90763

Method for the synthesis of arylsulfonylalkylamides

The present invention relates to a process for the synthesis of arylsulfonylalkylamides. Arylsulfonylalkylamides are substances used as plasticizers in polyamides, especially polyamides 11 and 12. It is important that these emollients do not decompose under the influence of heat. The plasticizer is added at high temperatures (200-250 ° C), i.e. it must not be a source of acidic compounds during use, which threaten to discolour and, on the other hand, impair the mechanical properties of the polymers (chain breakage). Patent application EP-7623 discloses a process for purifying arylsulfonylalkylamides with an alkaline substance at 200 ° C to give a thermostable substance. A process has now been invented for the synthetic preparation of arylsulfonylalkylamides which are thermostable and which can thus be used directly as a plasticizer in polyamides without the use of a purification process such as that described in EP-7623.

Houben-Weyl, Methoden der organischen Chemie, pp. 609-610, mentions on page 609 the last in the previous paragraph the reaction of benzene sulfochloride with a primary amine. The third line says that the unreacted sulfochloride is decomposed, which is the opposite of eo. in an invention with an excess of amine. On page 610, the last in the previous example is the reaction of ethanolamine with benzenesulfochloride, followed by removal of water by heating. Eo. the application relates only to alkylamines and the amine and water are removed in step b.

Ind. & Eng. Chem. butter. 46 (1954), p. 590, describes the reaction of benzenesulfonyl chloride with dibutylamine in a molar ratio of 1: 1. The aqueous phase is removed only in the separation step of the product and not before the separation as in eo. invention. Eo. the invention has the advantage that the product is purer than in the above methods.

2

The present invention relates to a process for the synthesis of arylsulfonylalkylamides of the formula: r3 r2; in the formula represents R 1, a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R 2 represents an alkyl group having 1 to 10 carbon atoms and R 3 represents one or more identical or different substituents selected from the group consisting of halogens and alkyls in which is not more than 5 carbon atoms, by the reaction of an aryl sulfohalide and an alkylamine, in which process a) the aryl sulfohalide is contacted with an excess of an alkylamine and an aqueous solution of an alkaline compound and the alkali compound is in excess of the aryl sulfohalide used, b) phase, c) arylsulfonyl-1-alkylamide is separated from the residue obtained in b).

Although R 1 and R 2 may be different, compounds in which R 1 and R 2 are identical and those in which R 1 and R 2 do not contain more than 3 carbon atoms are preferred are preferred. Another preferred group of substances are those in which R 1 is hydrogen and R 2 is alkyl, preferably having 2 to 6 carbon atoms and more preferably 4.

Of the substituents on the benzene ring, fluorine, chlorine, bromine and methyl are preferred. The ring may have several of these substituents simultaneously, i.e. it may have, for example, one methyl and one or more bromine atoms, or one methyl and one or more chlorine atoms. Particularly preferred compounds are those in which R3 is hydrogen, i.e. there are no substituents on the benzene ring, Rj is also hydrogen and Rj is alkyl having 2 to 6 carbon atoms.

Of these compounds, N, n-butylbenzenesulfonamide of the formula is preferably used: (δν ° 'Ν \ Γ N_ / CH2CH2CH2CH3 The starting aryl sulfohalide is a compound of the formula: Γ ~ \

(O) -s0jX

r3 wherein R3 is as defined above and X represents halogen. X preferably represents chlorine and bromine, and more preferably chlorine. The alkylamine used as a starting material is a compound of the formula: R 2 and R 2 wherein R 1 and R 2 are as defined above.

The reaction between the aryl sulfohalide and the alkylamine is practically complete and theoretically requires one mole of halide per mole of amine, and one mole of HX is obtained which is converted by means of an alkaline compound.

Preferably benzene sulfochloride is used, i.e. a compound in which R 3 is hydrogen and X is chlorine, and n-butylamine, i.e. a compound wherein R 1 is hydrogen and R 2 is n-butyl.

In step a) it is essential to use an excess of alkylamine, i.e. more than one mole of amine is used per mole of halide.

This molar excess is preferably 20%, i.e. 1.2 moles of amine per mole of halide used, and more preferably 5-15%. However, a large excess would not be excluded from the scope of the invention, but at the end of the reaction considerable amounts of amine should be returned to the cycle.

As the alkaline compound in aqueous solution, for example, alkali and alkaline earth metal hydroxides, carbonates, bicarbonates and alcoholates can be used. Sodium hydroxide or potassium hydroxide is preferably used, and preferably sodium hydroxide. Although the concentration of sodium hydroxide or potassium hydroxide is not important, 10-30% by weight aqueous solutions are usually used. The amount of alkaline substance required depends on the amount of sulfohalide used in a), and stoichiometrically corresponds to one time equivalent of one mole of sulfohalide, i.e. if potassium hydroxide or sodium hydroxide is used, it is required at least one mole per mole of sulfohalide. It is necessary to use an excess of alkaline compound relative to the stoichiometric amount defined above. Preferably a molar excess of up to 10% and more preferably 1-5% molar excess is used. The scope of the invention would not be eliminated by using a large excess of alkaline compound, but the process would be more complicated due to the large amounts of excess substance that must be removed.

One can work continuously or non-continuously and add the aryl sulfohalide, alkylamine and aqueous solution of the alkaline compound in any order, or partly in one order and partly in another order. The only condition to be met is that the aryl sulfohalide is not decomposed in the reaction with the alkaline compound. For example, an aryl sulfohalide can be contacted with an alkylamine and then an alkaline compound added. The aryl sulfohalide can also be drained into a mixed mixture of an alkaline compound and an alkylamine in aqueous solution. The term "mixed mixture" is used because the alkaline solution and the alkylamine are not usually mixed, and some kind of unstable emulsion is obtained by mixing. According to another variation, an aryl sulfohalide and an aqueous solution of the alkaline compound can also be poured into the alkylamine with a slight delay with the addition of the alkaline solution.

Il 5 90763 "Delay" is defined as the number of moles of an alkaline compound relative to the number of moles of aryl sulfohalide.

It is essential in the invention to provide contact between an aryl sulfohalide, an alkylamine, water and an alkaline compound, but it would not be outside the scope of the invention to use an anhydrous alkaline compound and water or an anhydrous alkaline compound and an alkylamine in an aqueous emulsion. The aryl sulfohalide may be used as such or dissolved in a solvent, the alkylamine may also be present as such or optionally in a solvent such as toluene.

Although step a) can be performed at any temperature and pressure, provided, of course, that the compounds do not decompose, it is preferred to work at or near ambient temperature and at or near atmospheric pressure such that the halide is liquid and the amine is likewise liquid. If it is impossible to combine these conditions, the pressure and temperature range is located, where the halide is liquid and the amine is gaseous. These conditions are preferably: a temperature lower than 150 ° C and a pressure lower than 5 relative bars.

It is preferred to work at atmospheric pressure and at a temperature close to ambient temperature, i.e. between 0-50 ° C.

The duration of this step a) is irrelevant, but the reaction is in the blink of an eye and its duration is tied to the practical conditions associated with the equipment and the amounts treated.

This duration is usually about 15 minutes to some hours.

This contacting is a prior art method and can be made from any equipment used in the chemical industry, preferably using equipment that can be mixed.

6

After all the reactants of this step a) have been brought into contact, the reaction medium is stirred continuously at a temperature in the range of 20 ° C to 100 ° C and preferably in the range of 40 ° C to 70 ° C, which may vary from a few minutes to a few hours and preferably from one hour to three hours. The reaction medium obtained at the end of step a) is then separated into an aqueous phase and an organic phase containing mainly aryl-alkylalkylamide, α-alkylamine and a few percent water. This separation of the two phases is a previously known method.

Step b) comprises removing water and alkylamine from this organic phase. It is preferable to carry out the distillation. It is possible to work under vacuum or at a pressure of some bars, provided that the temperature at which the organic phase begins to decompose is not exceeded, or the compounds are discolored or decomposition products are formed. This temperature o is usually less than 1Θ0 C. Preferably working between o 130-170 C. The scope of the invention would not be departed from working at a higher temperature, but then there is a risk of decomposition of the products, and it is much simpler to work at a lower temperature.

The duration of the work is irrelevant, it is determined by the practical conditions related to the equipment and the amounts of water and alkylamine to be removed.

This step b) as well as all other steps of the present invention can be performed continuously or non-continuously. Removal of all water and alkylamine gives an organic residue containing essentially the desired amide. Step c> is performed by any known separation support method. Preferably, distillation or one or more flash evaporations or membrane evaporations or evaporations from a thin layer are used and vacuum is used.

il 7 90763

In the following examples, the stability test comprises holding the arylsulfonylalkylamide for 3 h at 250 ° C under a nitrogen atmosphere, whereby the staining test must be less than 250 Hazen at the end of the test. The product can then be used as a plasticizer.

Unless otherwise stated, work is carried out in a glass reactor equipped with a stirrer, a heat-insulating housing, an injector for nitrogen purge, vertical coolers and cooling by means of a cold water bath or cooling solution. During distillation (steps b and c), a nitrogen protection factor is maintained on the products.

Example 1 a) During 1 1/2 h, 3 moles of benzenesulphochloride (CgHgSO2Cl) are drained into a mixture of 3.051 moles of sodium hydroxide in 19.37% aqueous solution and 3.3 moles of n-butyl-amine <CH3CH2CH2CH2NH2>. The reactor temperature is maintained at 20 ° C.

o

This temperature is then raised to between 60-65 ° C for 2 h. Decant to give 675 g of an organic phase containing 3x0.9959 moles of N, n-butylbenzenesulfonamide (C6H5SO2NHCH2CH2 CH2CH3) (BBSA).

b) distilling this organic phase to remove water and n-butylamine o and maintaining the lower temperature at 20-145 ° C under vacuum at 740-10 mm Hg for 1 h.

c) distilling the residue obtained in vacuo (0.5 mm Hg) and thus recovering 96% of the BBSA contained in the organic phase at the end of step a). The thermal test shows the staining of 50 Hazen.

Example 2

Work as in Example 1 except that the temperature is maintained at 50 ° C during the drainage of benzene sulphochloride. The results are identical to Example 1.

8

Example 3 a) 0.6 moles of benzene sulphochloride are drained into 3.3 moles of n-butylamine and the reactor is kept at 50 ° C. 3.051 moles of sodium hydroxide in the form of a 19.37% aqueous solution and 2.4 moles of benzenesulfochloride are then run simultaneously over 1 1/2 h, and the reactor is kept at 50 ° C. Add 7 g of water to rinse the sodium hydroxide drain ampoule. The reactor temperature is then raised to between 60-65 ° C for 2 h.

Decant to give 669 g of an organic phase containing 3x0.9939 moles of BBSA.

b) Distill as in Example 1.

c> Distill the residue obtained in vacuo at 0.5 mm Hg and thus recover 95% of the BBSA contained in the organic phase at the end of step a). The thermal test shows the staining of 50 Hazen.

Example 4

Work as in Example 2, but using a stainless steel reactor with a color tone of 304 L at the bottom and 316 L at the rest. Identical results are obtained.

Example 5 a) 3 moles of benzenesulphochloride are drained over 30 minutes into 3.3 moles of n-butylamine, the reactor temperature is maintained at 50 ° C. 3.15 moles of sodium hydroxide in the form of a 19.91% aqueous solution are then drained over a period of 1 1/2 h.

Rinse with 13.5 g of water in a sodium hydroxide drain ampoule.

o

The reactor temperature is raised to between 60-70 ° C for 2 h. Decant to give 671.8 g of an organic phase containing 3 moles of BBSA.

9 90763 b) Distillation of water and amine as in Example 1. It is noted that 6.1% of the weight used in b) has been lost during this distillation.

c) Distill off the residue obtained in vacuo <0.5 mm Hg) and thus recover 92¾ of the BBSA contained in the organic phase at the end of step a). The thermal test shows 75 Hazen staining.

Example 6 a) Work as in Example 3 except that the reactor is kept at 20 ° C instead of 50 ° C during both casting operations of the reactants. Decant to give 671.8 g of an organic phase containing 3x0.998 moles of BBSA.

b) Distillation of water and amine as in Example 1. It is noted that 6.07% by weight has been lost during this distillation.

(c) Distill the residue obtained in vacuo (0,5 mm Hg) and collect the 3 corresponding fractions of the distillation: first, middle and last fractions. (Percentages are by weight).

F1 = 4.9% F2 = 84.2% F3 = 7.1%.

3.8% of the weight used in step (c) remains in the flask as a percentage.

The thermal test for staining from F2 is less than 50 Hazen and from FI + F2 + F3 100 Hazen.

Example 7

Work as in Example 2 except that 3.75 moles of n-butylamine are used. 702.6 g of organic phase containing 3x0.9924 moles of BBSA are obtained. Identical results are obtained.

10

Example 8

Work as in Example 2 except that 3.15 moles of n-butylamine are used. 659.8 g of organic phase containing 3x0.9915 moles of BBSA are obtained. Identical results are obtained.

Il

Claims (6)

A process for the preparation of synthetic arylsulfonylalkylamides of the formula: (wherein O is R 2 represents a hydrogen atom or an alkyl group of 1-10 carbon atoms, R 2 represents an alkyl group of 1-10 carbon atoms and R 3 represents one or more identical or different substituents selected from a group consisting of halogens and alkyls having a maximum of 5 carbon atoms, by a reaction between an aryl sulfo halide and an alkylamine, in which process a) an aryl sulfo halide is contacted with an alkylamine and an aqueous solution of an alkaline compound, and an excess 90763 of the alkaline compound is used in relation to the arylsulfo halide, b) the water and alkylamine are removed from the organic phase obtained from step a), c) the arylsulfonyl alkylamide obtained is separated from the residue obtained from step b), characterized in that the aryl sulfohalide in step a) is contacted with an excess of the alkyl amide. Process according to Claim 1, characterized in that the molar excess of the alkylamine in relation to the stoichiometric amount is between 5-15%. Process according to claim 1 or 2, characterized in that the alkaline compound is sodium hydroxide. Process according to any one of claims 1-3, characterized in that the molar excess of the alkaline compound is between 1-5%. Process according to any of claims 1-4, characterized in that step b) is carried out by destination. Process according to any of claims 1-5, characterized in that the arylsulfonylalkylamide is N, n-butylbenzenesulfonamide: