MXPA01009192A - Method of preparing granular n-alkyl-ammonium acetonitrile salts - Google Patents

Abstract

The invention relates to an improved method for the preparation of granular N-alkyl ammonium acetonitrile salts of formula (I) R2R3N+R1-CR4R5-CN Y-in which R1 to R5 are hydrogen or organic rests and Y- is a sulfate or hydrogen sulfate anion;from an aqueous solution of the compound of formula (II) R2R3N+R1-CR4R5-CN R6O-SO2-O- in which R6 is C1 to C4 alkyl. According to the invention the aqueous solution is evaporated at a temperature of between 80 and 250°C and a pressure of between 10 mbar and 2 bar so as to obtain a melt and said melt is then left to solidify. During or after evaporation usual carrier materials and/or auxiliaries can be added. Lastly the resulting solidified compound (I) is given the desired granular form.

Description

METHOD FOR THE PREPARATION OF GRANULAR SALTS OF N-ALKYLAMONIO ACETONITRILO The present invention relates to an improved process for the preparation of granular N-alkylammonium acetonitrile salts of the formula I: R2R3N + R1_CR4- CN Y " in which R1 is a C? -C24 alkyl group which may be interrupted by non-adjacent oxygen atoms or may carry additional hydroxyl groups, a cycloalkyl group of Ci to C24, an alkaryl group of C7 to C24 or a group of the formula -CR3R5 -CN, R2 and R3 in each case, independent of each other, have the meaning of R1, or together they are a 4- to 9-membered, saturated ring, having at least one carbon atom and at least one other heteroatom of the group consisting of oxygen, sulfur and nitrogen, R4 and R5 in each case, independent of each other, are hydrogen, C- alkyl groups. to C24 which may be interrupted by non-adjacent oxygen atoms or may furthermore hydroxyl groups, C4 to C24 cycloalkyl groups or alkaryl groups of C. to C24, and And "is an acid sulfate or sulfate anion, in the corresponding stoichiometric amount, from a solution of the compound of the formula II: R ^ N -CR ^ -CN R0-S02"0" (ID wherein R1 to R5 are as already defined and R6 is C4-C4 alkyl.

The N-alkylammonium acetonitrile salts, such as N-methylmorpholinium acetonitrile sulfate and acid sulfate, are particularly required in detergents as activators in the form of solids for bleaching at low temperature. W098 / 23531 describes granules of these compounds, which can also comprise carrier materials, for this application. For the preparation of these sulfate or sulfate acid granules it is recommended to start from the metiisulfate salts.

However, known processes for the preparation of these solid, N-alkylammonium acetonitrile sulfates and sulfates still need improvement. It is an object of the present invention to provide a process that avoids the disadvantages of the prior art.

We have found that this objective is achieved by the present process, which consists in evaporating the aqueous solution of compound II at a temperature from 80 ° C to 250 ° C and a pressure from 100 mbars to 2 bars to obtain a melt, then leave that the melt solidifies, where, during or after evaporation, it is possible to add customary carrier and / or auxiliary materials, and the resulting solidified compound I is converted to the desired granular form.

During the evaporation step, the water and also the corresponding C -.- C alcohol which is released with the partial or complete thermal hydrolysis of the counter ion Y is removed from the aqueous solution of the compound II.

The radical R1, which has arisen normally as a result of the alkylation of the N atom is, for example: - a relatively long or relatively short chain straight or branched alkyl radical having from 1 to 24 carbon atoms, where unsaturated radicals are also suitable, in particular unsaturated fatty acid radicals, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, isononyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, iristyl, cetyl, stearyl or oleyl. - an alkoxyalkyl radical, for example, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 2-ethoxyethyl or 3-ethoxypropyl. - a hydroxyalkyl radical, for example, hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxy-2-butyl or 4-hydroxybutyl. - a radical constructed from repeated units of alkylene oxide of C2 to C4, such as ethylene oxide, propylene oxide or butylene oxide, which can be terminated by a hydroxyl group or an alkoxy group, for example, (C2H40) n-HO (C2H40) n-R7. - (C3H60) m-H OR - (C3H60) m-R7, - (C4H80) k-H or - (C4H80) k-R7 (n = 1 to 11, m = 2 to 7, k = 2 a , R7 = methyl or ethyl); - a cycloalkyl group such as cyclopentyl, cyclohexyl or cycloheptyl. - an aralkyl group such as benzyl, 2-phenylethyl, 3-phenylpropyl or 4-phenylbutyl. - a group of the formula -CH2-CN, -CH (CH3) -CN or -C (CH3) 2CN.

The preferred meanings for R1 are: an alkyl group of C -.-C. or a benzyl radical.

The meanings for radicals R4 and R5 are, in principle, the same as for R1 (with the exception of -CR4R5-CN), and these can additionally be hydrogen. The preferred meanings for R 4 and R 5 are hydrogen, ethyl and methyl, and in particular both are hydrogen.

In a preferred embodiment, R1 is a C1-C4 alkyl group or a benzyl radical, and R4 and R5 are both hydrogen at the same time.

The meanings for the radicals R2 and R3 are mainly the same as for R1 for open-chain alicyclic structures. In addition, R2 and R3 may, together with the N atom of ammonium, be a saturated heterocyclic ring. Suitable, in particular, in this context, are those which, apart from the N atom of ammonium, contain none, one or two of other heteroatoms of the group consisting of oxygen, sulfur and nitrogen, especially of the group consisting of oxygen and nitrogen . The sizes of the preferred rings are 5, 6 and 7-membered rings. Examples of the heterocyclic systems which are suitable for this purpose are imidazolidine, 1,2,3-triazolidine and piperazine.

Particular preference is given to systems in which R2 and RJ together are a 6-membered, saturated ring with 5 carbon atoms or 4 carbon atoms and an oxygen atom or a nitrogen atom. These are, in particular, the piperidine and morpholine systems.

The radical R6 is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl, preferably methyl.

According to the process of the invention, very particular preference is given to the preparation of N-methyl orfolinium acetonitrile sulfate granular acid from an aqueous solution of N-methylmorpholinium acetonitrile methylisulfate.

Depending on the pressure, the evaporation is carried out at temperatures from 80 ° C to 250 ° C, preferably from 90 ° C to 200 ° C, in particular from 100 ° C to 160 ° C. In the preferred pressure range, temperatures from 100 ° C to 160 ° C are particularly favorable because then the proper removal of water and alcohol takes place, and the decomposition of acetonitrile I to the corresponding amide step is still negligible.

The evaporation is carried out at a pressure of 100 mbars up to 1.1 bar, in particular at a pressure of 250 to 960 mbar. Preference is given to evaporation with a slight vacuum since under these conditions the secondary volatile components can be easily released.

The evaporation step is preferably carried out in a continuous process, for example in a Sambay evaporator, a thin film contact dryer, a falling film evaporator or a tube bundle heat exchanger. However, the evaporation can also be carried out batchwise, that is, in a batch process, for example in a reactor.

The residence time required for the evaporation step depends on the chosen temperature and the chosen pressure and is generally in the range from a few minutes to several hours. A common interval is from 2 minutes to 15 hours, in particular from 5 minutes to 5 hours. In the preferred temperature and pressure range, a residence time of 5 to 15 minutes is particularly favorable. The too long stay times can activate the decomposition of the product. The distribution of the stay time must be narrow, in the case of a continuous process, a piston-type expenditure pattern should be sought in order to avoid the formation of by-products and products of decomposition.

In a particularly preferred embodiment, the evaporation is carried out continuously with a residence time from 5 to 15 minutes.

Upon leaving the evaporation stage are the molten product and vapors in the form of water vapor and alcohol mainly. In the process according to the invention, the significant reduction in the energy consumption can be achieved with the condensation of the vapors produced during the evaporation to precorb the aqueous solution of the compound II. With respect to the apparatus, it is possible to use for this purpose, for example, tubular bundles or plate-type heat exchangers.

The melts produced in this way usually have a water content of not more than 30% by weight, in particular not more than 20% by weight, especially from 1 to 10% by weight. The proportion of the sulfate salt or acid sulfate I in the melt is usually at least 50% by weight, in particular at least 70% by weight, especially at least 80% by weight. The aqueous solution of the compound II used as raw material usually has a solids content of 5 to 80% by weight, in particular from 10 to 75% by weight, especially from 25 to 65% by weight.

/ Before solidification, it is possible to mix the melt with the usual carrier and / or auxiliary materials. These carrier materials can be water soluble or water insoluble, depending on the field of application. Examples of carrier materials that are added during or after evaporation are sodium sulfate, silicas and zeolites. It is also possible to add two or more of the carrier materials, i.e. mixtures thereof. Also as carrier materials it is possible to add functional auxiliaries as surfactants to the melt.

The mixing with the carrier or auxiliary materials can be carried out in any separate apparatus, for example in a stirred vessel or in a continuous mixer. It is then possible to solidify the mixture by contact cooling, for example, in a cooling roller, on a cooling strip or in a cooling mixer, by convection cooling, for example in a tower for granulation or in a granulation equipment by aspersion. However, it is also possible to carry out mixing and solidification of the melt in the same apparatus, for example in an extruder, kneader reactor or mixer with cooling.

The cooling process can be carried out at super atmospheric pressure, atmospheric pressure or at reduced pressure. In principle, it is possible to operate within the same pressure ranges as for the evaporation step. In the case of the cooling process, preference is given to carrying out the process at atmospheric pressure or, as in the case for the evaporation step, at slightly reduced pressure as a result of suction or suction.

The cooling temperatures can be in the range from the solidification temperature of the melt to very negative temperatures, for example, as is the case during cooling with liquid nitrogen (-196 ° C), preference is given to cooling temperatures in the range from -50 ° C to + 30 ° C, in particular from -20 ° C to + 20 ° C.

The necessary residence time of the solidification process depends on the crystallization properties of the mixture of the substances and is generally in the range from a few minutes (for example 5 minutes) to 1 hour. The intimate, perfect mixture, as it happens for example in the extruders or kneader reactors, can shorten considerably the time of crystallization necessary in many cases.

According to the solidification process, the product, which contains the salt I in addition to any of the remaining raw materials II and, optionally, the carrier and / or auxiliary materials, is usually in the form of a solid with a wide particle size distribution and thus still does not meet for example the requirements for the detergent granules. The desired granular shape with respect to the particle size can be obtained by suitable sieving and / or crushing steps with the customary processing equipment. The usual particle sizes are from 100 to 5000 microns, in particular from 300 to 2000 microns.

The process according to the invention has different advantages. For example, it allows the conversion with a low quantity of by-products and the reduction of volatile secondary components. The preferred continuous process produces high yields. Because the inventory in the plant is short, the continuous procedure is advantageous for safety reasons. The fact that it is possible to recover • heat means that the process is favorable from the point of view of energy. It is possible to use a very wide variety of carrier and auxiliary materials in the granulation process. In addition, the particle size distribution in the granulation process can be easily controlled.

Example An 80-liter glass container was charged with 60 liters of a 65% by weight aqueous solution of N-RETHYLMORPHYLINION acetonitrile methylisulfate. The solution was heated to 110 ° C and evaporated at a pressure of 600 bars for a period of 3 hours. The melt, which had a content of N-methylmorpholinium acetonitrile sulfate acid, of about 80% by weight (the remainder consisted practically of the inorganic salts and waters), was then introduced into 20 kg of a commercial, normal silica in a mixer. 160 liters Lddige, and the mixture solidified. The solidified mixture was then sieved to a particle size from 250 to 1600 microns. Coarse material greater than 1600 microns was crushed and then retained. This provided granules with a content of about 60% by weight of N-methylmorpholinium acetonitrile sulfate acid.

Claims (3)

1. A process for the preparation of granular N-alkylammonium acetonitrile salts of the formula I R2R3N + R1-CR4-CN Y "(I) in which R1 is a C? -C24 alkyl group which may be interrupted by non-adjacent oxygen atoms or may carry additional hydroxyl groups, a cycloalkyl group of Ci to C24, an alkaryl group of C7 to C24 or a group of the formula -CR3R5 -CN, R2 and R3 in each case, independent of each other, have the meaning of R1, or together they are a 4- to 9-membered, saturated ring, having at least one carbon atom and at least one other heteroatom of the group consisting of oxygen, sulfur and nitrogen, R4 and R5 in each case, independent of each other, are hydrogen, C_ to C2 alkyl groups which may be interrupted by non-adjacent oxygen atoms or may in addition hydroxyl groups, C to C2 cycloalkyl groups or C4 to C24 alkaryl groups , Y And "is an acid sulfate or sulfate anion, in the corresponding stoichiometric amount, from a solution of the compound of the formula II: R2RJN + R -CR4R -CN R ° 0-S02AT (II) wherein R1 to R5 are as already defined and Rd is C? -C4 alkyl. by evaporating this aqueous solution at a temperature from 80 ° C to 250 ° C and a pressure from 10 mbars to 2 bars to obtain a melt, then let the melt solidify where, during or after evaporation, it is possible to add the materials customary carriers and / or auxiliaries, and the resulting solidified compound I is converted to the desired granular form, wherein the hydrolysis of the counterion R60-S02-0 ~ a Y "takes place thermally, ie without the addition of acids .

2. The process for the preparation of granular N-alkylammonium acetonitrile I salts as in claim 1, wherein R1 is an alkyl group of C -.- C4 or a benzyl radical, and R4 and R5 are hydrogen. The process for the preparation of granular N-alkylammonium acetonitrile I salts as in claim 1 or 2, wherein R2 and R3 together are a 6-membered, saturated ring, having 5 carbon atoms or having 4 carbon atoms. carbon and an oxygen atom or a nitrogen atom. A process for the preparation of N-methylmorpholinium acetonitrile sulfate granular acid from an aqueous solution of N-methylmorpholinium acetonitrile methylisulfate as in claims 1 to 3. The process for the preparation of granular salts of N-alkylammonium acetonitrile I as in claims 1 to 4, wherein the evaporation is carried out at a temperature of 100 ° C to 160 ° C. The process for the preparation of granular N-alkylammonium acetonitrile I salts as in claims 1 to 5, wherein the evaporation is carried out at a pressure from 250 to 900 mbar.