MXPA94002683A - Procedure for the crystallization by fusion and procedure to produce a suspension of a massacredisation and suspension obtain - Google Patents

Abstract

The present invention relates to a process for the melt crystallization of an amido acid composition containing at least one amido acid represented by the formulas I, II: wherein R1 is selected from C1-14 alkenyl, arenyl and alkanyl, R2 it is selected from alkylene, arylene and alkarylene groups containing from 1 to 14 carbon atoms, R3 is hydrogen or an alkyl, aryl or aralkyl group containing from 1 to 10 carbon atoms, and n is 0, which comprises the steps of: preparing an aqueous medium having a pH of 2-6 comprising water and an effective amount of thickening agent to prevent coalescence of the amido acid in the water at a temperature at or above the melting point of the amido acid composition, heating said aqueous medium at a temperature sufficient to melt the amido acid composition, add said amido acid composition before, during or after heating in order to form a two-phase emulsion. is continuous, and cooling said two-phase emulsion to a temperature below the crystallization temperature of the amido acid at a controlled cooling rate to crystallize the amide

Description

"PROCEDURE FOR CRYSTALLIZATION BY FUSION AND PROCEDURE TO PRODUCE A SUSPENSION OF A COMPOSITION OF AMIDOACIDO AND SUSPENSION OBTAINED" Inventories): JUR3E ENBBERT DUINT3ER and CORNELIS ADRIAIMUS HUL, Dutch, with registered address en- ieermuidenseweg 27, 7361 TE Twello and Schipbeeksweg 4, 7437 BW Bathem, The Netherlands, respectively.

Causahabiente: AKZO NOBEL N.V., a Dutch company domiciled at: Velperweg 76, 6S24- BM Arnhep., The Netherlands.

SUMMARY OF THE DESCRIPTION The present invention relates to a process for the melt crystallization of an amido acid composition containing at least one amido acid represented by the formulas I and II: R 3 ~ -C-N-R 8-C ~. 0), - 0H R - -C-Ra-C- (0) r? 0H Formula I Formula II wherein R-1 is selected from C- alkenyl. ^, Aren i lo and alearen i lo, PZ-1'- is selected from alkylene, arylene and full alloy groups containing from 1 to 14 carbon atoms, R3 is hydrogen or an alkyl, aplo or aralkyla containing from 1 to 10 carbon atoms, and n is 0 or 15 comprising the steps of: preparing an aqueous medium having a pH of 2-6 comprising water and an effective amount of thickening agent to prevent coalescence of the amido acid in the water at a temperature at or above the melting point of the amido acid composition, heating said aqueous medium to a temperature sufficient to melt the amida acid composition, adding said amido acid composition before, during or after heating in order to form an emulsion of two continuous phases, and cooling said two-phase emulsion to a temperature below the crystallization temperature of the amido acid at a controlled cooling rate to crystallize the amido acid.

TECHNICAL FIELD The present invention relates to a process for the melt crystallization of amidacids which leads to improved properties of suspensions made of these melt crystallized amidacids. The invention also relates to a process for making suspensions that modalizes the melting crystallization process and suspensions made by this procedure. BACKGROUND OF THE INVENTION Organic peroxyacids are useful as fabric bleaching agents. As such, they are usually formulated in the form of either dry, granular, or aqueous suspension compositions, any of these products can be used in combination with detergent compositions. European Patent Application No. 106 627 describes a method for the manufacture of aqueous suspensions of solid organic peroxides whereby peroxides having at least a difference of 5 ° C between their melting points and the decomposition temperatures are suspended in an aqueous medium. In particular, an aqueous phase is prepared by dissolving or dispersing a protective colloid and at least one surfactant in water. The aqueous phase is mixed with an organic oxide. This mixture is stirred at a temperature above the melting point of the peroxide sufficient to allow the peroxide to be divided into fine particles in an aqueous emulsion. This emulsion is rapidly cooled to form an aqueous suspension of the peroxide. This process suffers from the disadvantage that it is limited to suspensions of particles with a diameter smaller than 30 μm as can be seen in the examples where the particle diameters are in the scale of a diameter of 10-15 μm and from the example Comparative 1 demonstrating that a suspension of particles having an average diameter of 50 μm can not be stably suspended by this method. A similar procedure is described in the Japanese patent nos. Mo. 35 9093-04-4 which again employs a protective colloid and a surface-active agent. This method differs in that the aqueous medium is first preheated to a temperature above the melting point of the peroxide before the addition of peroxide. European patent application 7 290 also describes a process for the preparation of peroxide suspensions wherein the initiator is heated to its melting point, then the initiator is finely divided in water while in the molten state, preferably in the presence of one or more emulsifiers and / or protective colloids, and the initiator is rapidly cooled in water so that the initiator does not melt for more than 5 minutes. minutes This procedure is only suitable for making suspensions of very fine peroxide particles, 90% of which have a diameter no greater than 10 jum. These suspensions are designed to be used in PVC polymerization. Additional methods for suspending some peroxyacids are known from European application 0 34-7 966, European patent application publication No. 0 4-35 379, European patent publication No. 0 1 6 124, European patent publication No. 0 160 34-2 and European Patent Publication No. 0 201 956, among others. However, none of these publications teaches or suggests a method for preparing a solvation of the amidoperoxy acids herein that do not suffer from a significant viscosity increase in storage. In addition, another method for suspending peroxyacids is described in the international patent application No. PCT / EP 92/02176 filed on September 21, 1992. More particularly, this process comprises the steps of running an aqueous suspension having a pH of 2-6 of a composition comprising at least one aidoperoxyacid, agglomerating said aqueous suspension of peroxyacid at a temperature of 0-20 ° C below the melting point of said peroxyacid composition, and cooling said agglomerated peroxyacid composition. at a temperature below 30 ° C. Although this method provides some improvement over the previously known suspension procedures for amide peroperoxides, the resulting suspension still tends to become significantly more viscous when stored at higher temperatures. In this way, the product may require storage at low temperatures in order to maintain its Theological stability. Accordingly, there is a need in the art for Theologically stable amido acid suspensions, as well as a method for being such Theologically stable suspeneions without adversely affecting one or more of the other properties of the bleaching materials and without the need for significant amounts of waterproof materials. In addition, there is a need in the art for suspensions of large particles containing amido acids, and, in particular, particle suspensions having an average diameter greater than about 30 μm.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a process for the crystallization by melting of a composition of a-Iacido acid containing at least one amido acid represented by the formulas I and II: R iCN-Ra-C- i 0) ... OH R INCR 2-C- (0) pOH U »I 1 - Formula I Formula II wherein R" * • is selected from C-x alkynyl arehenyl and alkanyl, R3 is selected from the group alkylene, arylene and alkarylene containing from 1-14 carbon atoms, Ra is hydrogen or an alkyl, aryl or aralkyl group containing from 1 to 10 carbon atoms and n is 0 or 1; comprises the steps of: A. preparing an aqueous medium having a pH of 2-6 comprising water and an effective amount of thickening agent to prevent coalescence of the amido acid in the water at a temperature above the melting point of the composition of amido acid B. heating said aqueous medium to a temperature sufficient to melt the amido acid composition and form a continuous two phase emulsion of the amide, said amido acid composition being added to the aqueous medium with agitation either before, during or after the heating, and C. cooling the two-phase emulsion to a temperature below the crystallization temperature of said amido acid composition at a controlled cooling rate to crystallize the amido acid. The present invention also relates to a process for making amido acid suspensions that modalizes the melt crystallization process described above and to suspensions made by this process. It has surprisingly been found that melt crystallization of the amido acids at elevated temperatures provides relatively large amido acid particle suspensions that are physically and chemically stable, and that remain pourable through an acceptable storage period, when compared to suspensions of the prior art. The invention and its additional advantages will be explained in greater detail in the following description.

DETAILED DESCRIPTION OF THE INVENTION The present invention is applied to a Ioacid. As used herein, amidacids include amidocarboxylic acids as well as amidoperoxycarboxylic acids. The amido acids can be represented by formulas I and II: R? -C-N-Ra-C- (0) r, 0H R 3 ~ -C-RS-C- (O) pOH Formula I Formula II wherein RA is selected from alkenyl of Ct_1 > +, aren, and alloy, R22 is selected from the groups alkylene, arylene, and alloy containing from 1-4 carbon atoms, R3 is hydrogen, or an alkyl, aryl, or aralkyl group containing from 1 to 10 carbon atoms and n is 0 or 1. These amido acids and methods for making them are described in the US patents 4-, 634, 551 and 4,666,063 and European Patent Application Publication No. 0 445 096, all of which are incorporated herein by reference. The preferred amido acids are the aidoperoxyacids of the formula III: wherein R 1 is an alkyl group containing 6-12 carbon atoms and R 4e a full alkyl group containing 1-6 carbon atoms. Preferred amidoperoxyacids are 4- non? Lam? Do-4-oxopero? But? Nono and 6-non? La? Da-6-oxo? Er oxy-hexanoic acid. At the end of the amido acid synthesis, the reaction is typically quenched with water and the products are filtered and washed. The wet cake thus obtained can be further processed according to the process of the present invention. Pure amido acids can also be used in the process of the present invention. The first step in the process of the present invention is to prepare the aqueous medium. The aqueous medium is set at a pH between 2 and 6 by the addition of an appropriate amount of a pH adjusting agent. The exact pH used will depend on the amido acid. For example, with the preferred amido acids a preferred pH is 2.5-4.5, with a pH of 3 being most preferred when an amido acid of the formula I is used., The aqueous medium also contains at least a thickening people. The thickening agent is used to adjust the viscosity. In the present process, some thickener is initially added to the aqueous medium to provide a structured liquid and to prevent coalecence of the deoxy acid composition. Once the melt rectalization procedure is complete, additional thickener can be added. The thickening agent comprises one or more polysaccharides, wherein at least 60% of the saccharide units in the polysaccharide bae structure are bound by a 1,4-β-ax ?. More particularly, from the publication, "Applications of Novel Biogume," Clare,. . Chemspec USA '' 6 Svmposium, the structures of vanas gomas are known. This article characterizes the structure of biogomas by the units in the base structure and the units in the side chains. Accordingly, the thickening agents for use in the present invention are polymers that have a base structure in which at least 60% of the saccharide units in the base structure are linked by the l, 4- bond. -ß-ox? and said polysaccharides are compatible with amido acids. By compatible, it is meant to imply that polysaccharides do not unduly influence the chemical and / or physical stability of azo acids. The desired Theological properties of the aqueous medium can be achieved by the use of these polysaccharide thickeners. Examples of such polysaccharides include natural gums such as xanthan gum, gum arabic, cartagenagen and agarose obtained from marine algae, and synthetic gums such as Alpha FloR, Rhamsan gum and Whelan gum. A sufficient amount of palisapartite used to provide a physically and chemically stable, pourable aqueous medium and generally about 0.1-5% by weight of the total aqueous medium and of the amido acid is a thickening agent, and most preferably 0.1-1 ° >; in peeo it is thickening agent. The aqueous medium also contains one or more optional ingredients including pH regulating agents, exothermic control agents, electrolytes and chelating agents, for example. The electrolyte can be formed in situ from the residual acid present in the wet cake or am-docid, or the electrolyte can be added separately to the aqueous medium. Examples of suitable electrolytes include sodium sulfate, potassium sulfate, magnesium sulfate, aluminum sulfate, sodium nitrate and borate salts. The amount of electrolyte will depend, among other things. of the specific amido acid, as well as the particular aqueous medium. In general, up to 30 by weight of the total composition can be electrolyte. Be can optionally incorporate chelators in the aqueous medium. Examples of suitable chelators are carboxylates, talents such as the ethylenediamine tetraacetate (EDTA), and the dietetic isopatin pentaacetate. DTPA)? polyphosphates, such as sodium acid pnofoephate (SAPP), tetrasodium pyrophosphate CTSPP) and sodium tripole phosphorylate (STPP); phosphonates, such as ethexydroxydi phosphonate (Dequest® 2010) and other sequestering agents sold under the trade name Dequest®; dipicolic acid, picolinic acid, citric acid and 6-h idroxiqu mol ina; and combinations of the above. Preferably, 0.01-10% by weight of talar chelate is employed. Most preferably, 0.1-5% by weight of the chelator is employed. The amido acid composition, and especially the aperoperoxyacid compositions, are preferably employed in the form of a wet cake which is fresh from the synthesis process. A typical composition will contain 30-60% by weight of amido acid, 35-65% by weight of water and the rest of organic impurities that comprise mainly unreacted starting materials. The a-acid composition is mixed in the aqueous medium by means of a suitable mixing apparatus. For example, a step blade driver may be used. The a-acid composition can be added to the aqueous medium before, during or after heating to a temperature at or above the melting point of the a-acid composition. The amido acid composition can be added to the aqueous medium at any temperature below the decomposition temperature of the araidoacid such as room temperature, but, in a preferred embodiment, the aqueous medium is first heated to a temperature at or above the melting point of the composition of a aidoacid. Then, the amido acid composition is added to it. In this way, the decomposition of the amido acid, which can occur at elevated temperatures, is kept to a minimum. Most preferably, the aqueous medium is 0-1-15 ° C above the melting point of the amido acid composition when the a-acid composition is added. Although an aqueous medium is used, this places a limitation of 100 ° C on the melt crystallization temperature. However, the amido acid compositions having a higher melting point can be melt crystallized by the process of the present invention. More particularly, it can be added to be crystallized by melting by the pi presentment of the present. More particularly, a material can be added to the aqueous medium to raise the boiling point. Certain salts and glycols can be used. Another alternative is to employ one or more fatty alcohols, fatty acids or fatty esters as diluents in the amido acid composition, whereby the melting point of the amido acid composition can be reduced below 100 ° C. The most suitable material is lauric acid. The references to the melting point of the amido acid composition do not refer to the melting point of the pure amido acid, but refer to the melting point of the composition comprising the amido acid, such as the wet cake. After the addition of the composition of amido acid to the aqueous medium, if necessary, the pH is returned 2-6 by another addition of the appropriate agent, in this case, usually sodium hydroxide. Afterwards, the aqueous medium is heated to a temperature sufficient to melt the amido acid composition and stirred until a doe-faees emulsion of the finely divided amido acid is formed. The emulsion is normally formed in a period of 2-15 minutes. It is desirable to minimize the time during which the amido acid is maintained at a temperature above the melting point in order to minimize decomposition thereof. Accordingly, it is preferred to add the amido acid composition to the aqueous medium only after it has been heated. In addition, once the emulsion is formed, it is preferable to immediately initiate cooling to crystallize the amida acid. the cooling of the doe faee amido acid emulsion should be carried out at a carefully controlled rate, such as 0.1-10.0 ° C per minute, until the crystallization of the amido acid is complete. If the emulsion is cooled very rapidly, for example by extinction, a poor crystal structure is formed which leads to the inetability of the crystalline structure of the amido acid. In order to obtain an optimum crystal structure with a minimum decomposition of the amido acid, a cooling speed of 0.5-5.0 ° C per minute is preferred. Most preferred is a cooling rate of 1-3 ° C per minute. The cooling rate specified above only applies in the vicinity of the crystallization temperature of the amido acid. Since the solubility of the amido acids in the aqueous medium is very poor, the crystallization is complete when the aqueous medium reaches a temperature just below the crystallization temperature. In the euceeivo, the speed of cooling is no longer critical since it can not influence the crystal structure. In this way, for an a-acid composition with a melting point of 67 ° C, the cooling rate should be controlled on a scale of 75 ° C-60 ° C to ensure the formation of a stable crystal structure. In general, the cooling rate is important within approximately 10 ° C of the melting point of the amidacid composition and, most preferably, the cooling rate ee maintained until 1 ° C. The suspension obtains a temperature of at least 5 ° C below the melting point of the amido acid composition. Once the cooling is complete, a product of a hydrochloric acid is obtained. This product has a more stable crystalline structure, as well as a larger particle size than the amino acid in the wet cake and thus leads to the production of stable amido acid suspensions. The above melt crystallization process can be used advantageously as an integral part of a melting process. More particularly, the melt crystallization process in an aqueous suspension medium can be advantageously carried out in order to produce aqueous suspensions of eetablee of amido acid. When a suspension is made, in addition to water, a thickening agent and the other optional ingredients mentioned above, the aqueous suspeneion medium may also contain a second polymer. The second polymer improves the physical stability of the suspensions particularly in the case where high concentrations of amidacid are desired. The second polymer is selected from the group consisting of polyvinyl alcohols, including partially saponified polyvinyl acetates, polyvinylpyrrolidone, and one or more cellulose derivatives including cellulose ethers. Of particular advantage to be used in the suspensions of the preeent are met i Iceluíosa, put lh idrax iprop i Icelulosa, put ihidro ibutil-cellulose, hydroxyethylcellulose and carboxymet icelluloea. The amount of the second polymer it is generally from about 0.02 to about 2% by weight of the suspension. Any one or more of the thickening agents within the scope of the invention can be combined with one or more of the second polymers and / or one or more of the other optional ingredients to provide sleep-keeping within the scope of the invention. The aqueous suspension medium may also contain one or more additional optional ingredients such as brighteners and perfumes. In order to make suspensions using the melt crystallization process of the present inventionThe melting crystallization process is carried out just as described above, until a stable amido acid succination is obtained. After, instead of separating the amido acid, simply the suspension formed is used. In certain cases, it may be desirable to subject the suspension to high shear conditions in order to break some of the larger agglomerates that form during the melt crystallization process. It is generally desirable, in the present invention, to make suspensions with an average particle diameter of 30-100 μm and, most preferably, an average particle diameter of 40-70 μm. Additional thickeners may also be added to adjust the viscosity of the suspension to the desired level. These stable suspensions exhibit good physical and chemical stability, as well as stability under high temperature storage conditions that normally cause significant stickiness of comparable substances. The suspensions may be used, for example, as a liquid bleaching agent composition for washing textiles or bleaching. The present invention will now be described by the following examples. In the following and use, the viscosity is measured by a Brayfield type RVT viscometer equipped with a spindle set. The loss of active oxygen was measured by iodometca titration. The pH was measured with a normal pH glass electrode (example Ingald) and a pH meter (Metrohm). All suspensions were made in normal glass reactors equipped with step blade glass impellers.

EXAMPLES! - «+ AND COMPARATIVE EXAMPLE A Preparation of aqueous suspensions by fusion crystallization. As the starting material, a wet cake containing noni acid idoperoxydic acid (NAPAA) with an average particle diameter of 15 μm was used. First, an aqueous suspension medium containing water, effector agent, second polymer and chelating agent was prepared and heated to 75 ° C. After drying, the wet NAPAA cake was dosed for a period of 10 minutes with stirring to form a 2-phase emulsion of molten bath of = -m? Doperox? Acid. After. , the emulsion was cooled to the cooling rate presented in block 1. For examples 1-4, the cooling rate refers to cooling on the temperature scale of 75-60 ° C, while for example A Cooling speed refers to cooling on the temperature scale of 70-55 ° C. April lantadoi and perfume were added and the pH adjusted to 4-.S. The stability data for this = materials are presented in table 1. The formulations for each example were identical and are stated below.

Component% by weight NAPAA 11.50 Dipicolinic acid 0-25 Rhodopol ™ 23 (xanthan gum) 0.50 Polyvinyl alcohol3 1.00 Brightener FWA-4-953 0.10 Rainforest ™ perfume 3 # * 0.10 Water Polyviol ™ Rest M0E.-290 (ex. Wack er-Chemie) 3 Tinopal ™ CBS-X FWA-49 (fluorescent whitening agent) 3 e. J.E. Sozío Inc., New Jersey, SZ-4767.

The exact procedure to prepare the suspensions is as follows: A 2-liter glass reactor was charged with 1100 g of demineralized water and 3.75 g of dipicolinic acid (DPA). As the DPA dissolves, the pH falls to 2. The pH was then adjusted, with stirring, to 3 with a solution of caustic soda (10% NaOH). Successively, 4.5 g of Rhodopol 23 and 15.0 g of polyviol ™ M05-290 were sprayed into the solution with agitation at 300 rpm. Then, the aqueous suspension medium was heated to 75 ° C.

Upon reaching 75 ° C, 4-50 g of the NAPAA wet cake containing 39.3% by weight of NAPAA were added during a period of 10 minutes with continuous agitation. When the whole NAPAA was merged, it obtained an emulation of homogeneous doe faee, liea. With a few drops of a caustic soea solution, the? F-i was adjusted to 3 and jacket cooling initiated. A cooling rate of 75-60 ° C was used for 1 ° C / min. And the stirring was continued at 400 rpm. The crystallization of NAPAA started at 67 ° C indicated by an increase in viscosity and a slight increase in temperature due to the heating of the crystallization. At 60 ° C, cooling was continued more rapidly until the ambient temperature was reached. When the temperature reached 30 ° C, 1.5 g of FWA-4-9 polish was slowly sprayed into the suspension to improve whiteness and brilliance. Finally, after reaching room temperature, the pH was adjusted to 4-5 with a caustic soda solution and the euepeneion was deagglomerated with an Ultra-Turrax ™ for 4 minutes with a coarser TP 45/28 generator and 1.5 minutes with the fine generator T 45 / 6G. At the end of the agglomeration with Ultra-Turrax ™, the temperature of the suspeneion was 30 ° C. The suspension was again cooled to room temperature with a cold water bath and vacuum deaerated to remove dispersed air. Finally, an addition of 0.15% by weight of the Rhodapol ™ 23 thickener was added to adjust the viscosity to the desired level. Finally, 0.10% by weight of Rainforest ™ perfume was added to the suspension and the rheological and chemical properties of the suspension were measured during a storage period of 10 weeks at both ambient and 37 ° C temperatures. For example 2-4 and A, the cooling rate varied. In addition, for each of these examples, the NAPAA was added to the suspeneion medium before heating to 75 ° C. Also, the absolute quantities of each ingredient were varied slightly, using 1170 g of water and 290 g of the NAPAA wet cake in the plos 2-4- axis. Finally, in Example A, 670 g of water and 290 g of the NAPAA wet cake were used and the hot euepension was first cooled by rapidly cooling to 70 ° C by adjusting the heating jacket and then emptying 300 g of cold water ( 1 ° C) to the emulsion for a period of 30 seconds to cool from 70-55 ° C. At 55-20 ° C, the cooling rate was 3 ° C per minute.

TABLE 1 Example the perfume-free Ib with perfume Viscosity Brookfield RVT spindle 3. RPM 100 starts 276 mPas 273 mPae 1 day room temperature 317"305" 2 days "312" 307"5 days" 322 316"1 week" 326"326" 2 weeks "330" 316 4 weeks "333" 326"0 weeks" 355"343" beginnings 276 mPas 261 mPas 1 day 37 ° C 351 353"2 days" 347"349" 5 days "376" 366 1 week "366" 401"2 weeks" 4-10"4-26" 4- weeks "4-02" 4-22"0 weeks" 4-16"446" Loss of 0 available 6.6% after 10 weeks at 37 ° C early pH 4. '+9 after 10 weeks 3.92 Particle Size Distribution (DTP) (Malvern) d 10 - d 50 - d 90 - d 99 -.

Density s (kq / m3) start 1022 4 weeks; TABLE 1 Execute 2 3 1+ A (0.3 ° C / mip) (1.0 ° C / min) (3. 0 ° C / min) (3 .0 ° C / min) extinction Viscosity: (mPas) Brookfield (RVT) spindle 3 RPM 100 Start s 216 266 262 279 1 week 37 ° C 364 402 416 553 2 weeks 37 ° C 417 4-36 452 647 4 weeks 37 ° C 426 4-61 476 652 deepuée 4- after 4 after 4- after 4 weeks weeks week and weeks 2mm without without separating. of separ. of separ. of separ. of f se phase f se f Loss of OD (37 ° C) (4 weeks) (-6.4%) (-5.6% &) (-4 -.!%) (-4.2%) pH: beginnings 4-.52 4.4-5 4.53 4- . 5 after 4 weeks 4.09 4.21 4-.29 4.29 (37 ° C) DTP (Malvern) (mieras) d 10 6.3 14-.4 14.7 6.2 d 50 31.0 77.1 65.9 32.2 d 90 65.6 135.6 119.2 64.6 d 99 121.0 17 .7 164.4 124.6 Density (Ka / m3) start; 1020 1026 1024 1023 after 4 years 1025 1023 1029 - * EXAMPLES 5- > Suspensions of NAPAA, noni lamidoadipic acid (NAAA) and noni idoperoxysuccinic acid (NAPSA). In example 5, the following procedure was employed. A 2 liter glass reactor was charged with 460 g of demineralized water, 2.50 g of DPA and 500 g of the NAPSA wet cake. The mixture was stirred at 350 rpm and made homogeneous and then 3 g of Rhodopol "rM 23 and 10 g of Palyvial ™ M05 / 290 were added with continuous stirring.The pH was adjusted to 3 with a 10% hydroxide solution of sodium and the mixture was heated to 66 ° C to obtain a two-phase emulsion of NAPSA, melted.From 66.55 ° C, the cooling rate was 1 ° C / min.Two temperature stabilizations occurred, one at 63 ° C and the other at 59 ° C. When the temperature reached 55 ° C, the cooling rate was increased to approximately 3 ° C / min and cooling was continued at room temperature At about 40 ° C, FWA brightener was added. -4-9 and at 22 ° C the pH was adjusted to 4 -.5 with a 10% solution of sodium hydroxide, then the suspension was deaggregated with Ulta-Turrax ™ as in Example 1 and no extra thickener was required. Before storage, the Rainfarest ™ perfume was added with agitation.The results- appear in table 2 ac The suspension of Example 6 was prepared by loading a two-liter glass reactor with 1290 liters of demineralized water, 3.75 g of DPA, 160 g of NAAA flakes, 4-5 g of the Rhodopol ™ thickener and 15 g of Polyviol. ™ M05 / 290. While stirring, the pH of the suspension was adjusted to 3 with caustic soda. The suspension was heated after 67 ° C to obtain a two-phase emulsion. The emulsion was cooled to 67 ° C-75 ° C at 1 ° C / min and then reattached to room temperature. At 30 ° C, 1.5 g of the brightener 49 was added. The pH was adjusted to 4.5 and the de-agglomerated with Ultra-Turrax®. Finally 0.2% of the Rhodopal ™ thickener and 0.1% of the Rainforest ™ perfume were added. The results appear in table 2 below.

TABLE 2 EXAMPLES 7-6 AND COMPARATIVE EXAMPLE B Use of other additives in suspensions. In Example 7, exemplary 2 was repeated except that 7.5 g of citric acid was used in place of dipicolinic acid as the chelating agent. The results are presented in Table 3. In Example 6, Example 2 was repeated except that 1% by weight of polyvinyl Ipirralidone was used instead of PVA. The results are presented in Table 3. In Example B, 0.7% guar gum was used instead of xanthan gum. The guar gum being a polysaccharide which does not receive 60% of 1,4-β-oxy bonds in its polymer structure, is outside the scope of the present invention. The results with guar gum are shown in table 3.

TABLE 3 Example 7 6 B% by weight Water rest rest rest NAPAA 11.50 11.50 11.50 DPA 0.25 - 0.25 Citric acid 0.50 Rhadapal ™ 23 0.50 0.50 Gum Guar 0.70 PVA M05-290 1.00 1.00 PVP K15 1.00 Brightener 49 0.10 0.10 0.10 Perfume 0.10 0.10 0.10 Viscosity (mPas) Brookfield RTT Spindle 3, RPM 100 Start 267 256 303 1 week 37 ° C 4-66 376 72 2 weeks 37 ° C 4-72 417 separate 4 weeks 37 ° C 502 457 after 1 week Loss of OD (37 ° C) after 4 weeks (-5.6%) (-7.4%) PH Home 4-.4-9 4.49 4.51 DTP; (Malvern) (mieras) d 10 12.9 7.0 16.6 d 50 66.6 35.4 62.6 d 90 126.5 66.4 139.3 d 99 172.7 109.7 176.4 Density s (kq / m3) Start 1020 1027 1022 COMPARATIVE EXAMPLE C Starting with some of the wet peroxyacid cake as used in Example 1, a pellet containing 10.2% in pepa of NAPAA, 0.25% in peeo of dipicol acid was prepared. only 1% in polyethylene alcohol, 0.5% in weight of xanthan gum and the rest water by mixing the ingredients with stirring at a temperature below the melting point of the amido peroxyacid composition. The suspension of desaglamero later with Ultra-Turran ™ to provide a suspension with an average particle size of 13pm. This suspension was emptied and had an initial viscosity of 270 mPa.s. After one week of storage at 37 ° C, a gel structure was formed and the suspension was no longer pourable and had a viscosity of more than 10,000 mPa.s.

EXAMPLE 9 AND COMPARATIVE EXAMPLE D In Example 9, the procedure of Example 1 was followed except that the aqueous suspension medium contained 1200 g of demineralized water, 7.5 g of lac citric acid. and 15 g of Rhodapol ™ thickening agent. A stable emulsion was obtained. In Comparative Example D the procedure of Example 9 was followed except that the spiking agent was replaced by polyvinyl alcohol (Polyviol ™ M05 / 290). During the heating, the coagulation of the molten amidoperoxy acid occurred and an unstable emulsion was obtained. If the agitation is discontinued, the phase separation is established instantaneously. The above examples were presented for the purpose of illustration and description only and are not constituted as limiting the scope of the invention. The subject matter of the invention will be determined from the appended claims thereto.

Claims (7)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for the crystallization by melting of a composition of a-Iaacid containing at least one amido acid represented by the formulas I and II; R * -C-N-R «-C- (0) r, QH R J-N-C-R2-C-> 0) -. GH Formula I Formula II wherein R is selected from Cx-m alkenyl, arenyl and alkanyl, Rs is selected from alkylene, aplene and alkylene group containing from 1-14 carbon atoms, R3 is hydrogen or an alkyl group, eg aralkyl containing 1 to 10 carbon atoms, and n is 0 or 1? being characterized in that it comprises the steps of A. preparing an aqueous medium having a pH of 2-6 comprising water and an effective amount of thickening agent to prevent coalececence of the amido acid in the water at a temperature above the flash point. the composition of amidacid? B. heating said aqueous medium to a temperature sufficient to melt the amidocid composition and form an emulsion of two continuous phases thereof, said combination of amido acid being added to the aqueous medium with agitation either before, during or after the heating, and C. cooling the two-phase emulsion to a temperature below the crystallization temperature of said amido acid composition at a controlled cooling rate to crystallize the amida acid.

2. A process for the fusion crystallization of an amidacid composition according to claim 1, further characterized in that the aqueous medium comprises an effective amount of a chelating agent for the ores by subtracting all metal ions that can to be present in the aqueous medium and / or composition of a-acid.

3. A process for the melt crystallization of an amido acid composition according to any of claims 1-2, further characterized in that the a-ida acid comprises 1-40% by weight with respect to -. the total composition.

4. A process for producing a suspension of an amido acid composition containing at least one amido acid represented by formulas I and II; R ^ -CN-R8-C (0) ... OH R i_ | M_c-Ra-C-> 0) - OH Formula I Formula II wherein R ee is selected from alkenyl of 0 .-.! - » , arenyl and alcarenyl, R2- 'is selected from the groups alkylene, apleno and full alloy containing i-Í4 carbon atoms, R3 is hydrogen or an alkyl, aplo or aralkyl group containing 1 to 10 carbon atoms, and n is O or 1? being characterized because he learns the steps of; A. Preparing an aqueous suspension medium having a pH of 2-6 comprising water and an effective amount of a thickening agent to prevent coalescence of the amido acid in the water at a temperature above the melting point of the composition of a Iatinate, B. Heating said aqueous suspension medium to a temperature at or above the melting point of the a-acid composition to form a continuous, 2-phase emulsion, said a-amino acid composition being added to the aqueous medium with agitation either antee, during or after the warming; and C. Cooling said two faee emulsion to a temperature below the crystallization temperature of said amido acid composition at a controlled cooling rate to form a suspension of said amidacid.

5. A method according to claim 4, further characterized in that said aqueous suspension medium comprises 0.02-2.0% by weight of at least one second polymer. 6.- A procedure in accordance with any 3- of claims 4-5, further characterized in that it comprises the step of de-agglomerating the amido acid suspension by subjecting it to high shear stress. 7. A method according to any of claims 4-6, further characterized in that the aqueous suspension medium comprises an effective amount of at least one chelating agent to sequester substantially all the metal ions in the suspension.

6. A method according to any of claims 4-7, further characterized in that it comprises the step of adding at least one brightening agent and at least one perfume to the suspension either during or after said cooling step. 9. A suspension of amido acid made by the process of any of claims 4-ß. In testimony of which I sign the above in this Mexico City, D.F. , on the 13th day of the month of April 1994. By AKZO NOBEL N.V. GD / crg * gfc * mvs *