MXPA98002179A

MXPA98002179A - Synthesis of oxides of amina tercia

Info

Publication number: MXPA98002179A
Application number: MXPA/A/1998/002179A
Authority: MX
Inventors: Sitaram Prabhu Vaikunth
Original assignee: General Electric Company
Priority date: 1997-03-20
Filing date: 1998-03-19
Publication date: 1999-02-24

Abstract

A process for the manufacture of solid, free-flowing tertiary amine oxides having N-nitrosodimethylamine levels of less than about 250 ppb is provided, the process comprising heating a mixture of a tertiary amine, a polar hydroxyalkyl solvent, an organic acid and peroxide of aqueous hydrogen, followed by the removal of the solvent and water, preferably by azeotropic removal, the resulting tertiary amine oxides have a suitable color without bleaching and are sonless without further purification

Description

SYNTHESIS OF TERCIARY MINE OXIDES FIELD OF THE INVENTION The present invention relates to a process for the manufacture of free flowing solid tertiary amine oxides having nitrosamine levels of less than 100 ppb. The process comprises heating a mixture of a tertiary amine, a polar hydroxyalkyl solvent, an organic acid and an aqueous hydrogen peroxide, followed by the azeotropic removal of the solvent and water. The resulting solid tertiary amine oxides have a suitable color without bleaching and are useful without further purification.

BACKGROUND OF THE INVENTION The tertiary amine oxides are widely used in commercial form as organic surfactants. Such surfactants have properties that make them very useful in shampoos, hair conditioners, dishwashing and laundry detergents, fabric softeners and the like. In these applications, the tertiary amine oxides are used as aqueous solutions. However, recently there has been an interest in the use of tertiary amine oxides as additives for thermoplastic resins. In these new additive applications it is important to have a high level of solids, preferably a solid tertiary amine oxide containing a minimum amount of volatile solvents to avoid difficulties in the removal of the solvent during the mixing and processing operations. N-rosamines have been reported as minor byproducts in the conventional preparation of tertiary amine oxides using aqueous hydrogen peroxide. Although the amount of nitrosamine is very small, in the order of only a few parts of one hundred per billion (ppb), this small amount makes amine oxide unsuitable in many applications including human contact. This is because it has been reported that nitrosamines are carcinogenic and / or mutagenic agents. Therefore, there is a need for a method for manufacturing tertiary amine oxides in high conversion and yield and at a rapid reaction rate, while producing tertiary amine oxide products which are solid at ambient temperatures and which are substantially free of charge. nitrosamines (ie, having a level of N-nitrosodimethyl amine of less than about 100 ppb). The present invention provides said method.

TECHNICAL BACKGROUND It has been generally reported that tertiary amine oxides are manufactured by the reaction of a suitable tertiary amine with aqueous hydrogen peroxide. Said procedures are reported in the patent of E.U.A. No. 4,748,275 (Smith et al.) And in the references mentioned herein. The reaction is typically conducted at 50-75 ° C and requires a long reaction period to obtain a complete conversion of the amine. It has been reported that promoters increase the speed and degree of conversion. Carbon dioxide appears to be a preferred example, as reported in the procedures of the U.S. patent. No. 4,247,480 (Murata et al.). These aqueous procedures are quite satisfactory for the products that will be used in applications in which their water content can be tolerated. Oxidation of tertiary amines has also been reported in organic solvents, such as in the U.S. Patents. Nos. 3,776,959 (Stalioraitis et al.); 4,659,565 (Smith et al.); 4,48,275 (Smith et al.) And 5,130,488 (Smith et al.). These procedures are also very satisfactory for some purposes, but the products formed or are oily in nature, or the procedures have undesirable limitations in the water to solvent ratios that can be used. For example, the process described in the U.S.A. No. 5,130,488 (Smith et al.) Limits the ratio of water to organic solvent to 2.1 / 1 in order to recover the amine oxide from the reaction mixture. It has now been discovered that solid tertiary amine oxides which are substantially free of nitrosamines (i.e., have a level of N-nitrosodimethyl amine of less than about 100 ppb) can be produced in a high yield and at a rapid reaction rate, by reacting a suitable tertiary amine in a polar hydroxyalkyl solvent with an organic acid and aqueous hydrogen peroxide , followed by the azeotropic removal of the solvent and water. The resulting tertiary amine oxides are free-flowing solids which have a suitable color without bleaching and which are useful without further purification.

DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of the invention is a process for making an amine oxide substantially free of nitrosamine which is a free flowing solid at room temperature (ie, 23 ° C), by reacting a tertiary amine capable of forming an oxide of amine in a polar hydroxyalkyl solvent at about 50-100 ° C with a promoter and with aqueous hydrogen peroxide, followed by azeotropic removal of the solvent, organic acid and water. By free flowing solid it is intended to mean a solid material that does not agglomerate (ie, agglutinate) in the form of particles and / or does not adhere to other surfaces. A free flowing solid can be characterized as easily transferable between containers without appreciable loss of the solid due to its adhesion to the first container.

In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: L wherein Ri and R2 are each independently an alkyl portion of Cs-30. In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: ## STR2 ## wherein R1 and R2 are each independently an alkyl portion of Ciß-is; and wherein the amine oxide absorbs less than about 10% by weight of water when stored at 23 ° C and 80% relative humidity, and is a solid at 23 ° C. In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: H3C-N-RI, < 2 wherein R1 and R2 are each independently an alkyl portion of C20-22; and wherein the amine oxide absorbs less than about 5% by weight of water when stored at 23 ° C and 80% relative humidity, and is a solid at 23 ° C. In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: 0 t, wherein R1 and R2 are each independently an alkyl portion of Cio; and wherein the amine oxide has a loss index at 10% by weight of at least about 120 ° C, when measured at a heating rate of 20 ° C / minute. In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: < 2 wherein R1 and R2 are each independently an alkyl portion of Ciß-is; and wherein the amine oxide has a loss rate at 10% by weight of at least about 145 ° C, when measured at a heating rate of ° C / minute. In another preferred embodiment, the present process produces a tertiary amine oxide of the general formula: wherein R1 and R2 are each independently an alkyl portion of C20-22; and wherein the amine oxide has a loss rate at 10% by weight of at least about 220 ° C, when measured at a heating rate of 20 ° C / minute. In general, the process of the present invention is applicable to any tertiary amine capable of forming an amine oxide. However, to obtain a tertiary amine oxide which is solid at room temperature, the tertiary amine should have the general formula: R3 -N-R5 A. wherein R3 is an alkyl portion of C1-30 and R4 and R5 are each independently an alkyl portion of Cs-30. For use as thermoplastic additives, it is preferred that R3 is a methyl group and R * and R5 are each independently an alkyl portion of Cs-30. However, at least one group R may optionally contain at least a portion -0-, -S-, -SO-, -CO2-, -CO- or -CON-. In another embodiment of the present invention, the tertiary amine may be a polymethyl amine. A polymethyl amine is intended to mean a compound or resin that contains on average more than one tertiary amine. Illustrative poly tertiary amines include the tertiary amine analogs of aliphatic and alicyclic diamines such as, for example, 1,4-diaminobutane; 1,6-diaminohexane; 1,10-diaminodecane and 1,4-diaminocyclohexane; and aromatic base diamines such as, for example, diaminoanthraquinones and diaminoanisoles. Also included are tertiary amines derived from diamine oligomers and polymers. Useful tertiary amines also include tertiary amines attached to polymers, for example, polyolefins, polyacrylates, polyesters, polyamides, polystyrenes and the like. When the tertiary amine is attached to a polymer, the average number of tertiary amines per polymer can vary widely, since not all polymer chains need to contain a tertiary amine. Generally, a useful number of tertiary amine portions in the complete polymer is between about 0.001% by weight and about 5% by weight, based on the weight of the polymer. All the aforementioned tertiary amines may optionally contain at least a portion -0-, -S- -SO-, -CO2-, -CO- or -CON-. Especially preferred tertiary amines, due in part to their wide commercial availability at a high purity and a relatively low cost, include didecyl methylamine (i.e., R * and R5 are each mainly a Cι), dicocomethylamine (i.e., R-) 4 and R5 are each mainly a Cio-e), disbomethylamine (i.e., R * and R5 are each mainly a Cie-is), diethylsilyl-methylamine (i.e., R-4 and R5 are each primarily a C20), and didocosanylmethylamine (ie, R * and R5 are each mainly a Q22), as well as mixtures of tertiary amines containing at least one of the amines mentioned above. It should be noted that these tertiary amines are generally commercially available enriched by at least 80% with the aforementioned alkyl groups; however, other alkyl amine fractions are present in the tertiary amines. Although a higher purity of a single tertiary amine may be desirable for some applications, the cost of producing tertiary amines of extremely high purity may be prohibitive. As previously mentioned, it is an object of the present invention to provide a simple and inexpensive process for preparing tertiary amine oxides which are free-flowing solids at room temperature and which have a low nitrosamine content. To achieve this objective, the tertiary amine used as the starting material must have a total content of primary and secondary amines of no more than about 1% by weight, preferably less than about 0.5% by weight. These tertiary amines can be obtained by distillation from the relevant tertiary amines having unwanted primary and / or secondary amines present from the tertiary amine preparation. Alternatively, sweepers can also be added which selectively react with the primary and secondary amines to reduce the level of primary and secondary amines. The sweepers that can be used for this purpose are in principle substances that react faster with primary and secondary amines than with tertiary amines, and whose reaction with these amines takes place as completely as possible after a short time. Useful sweepers include those found in the U.S.A. No. 5,543,515. Illustrative scavengers include the following classes of compounds: halogen formates, halogenformamides, carboxylic anhydrides, acyl halides, carboxylic esters, ketenes and their dimers, phosgene, carbonic esters, rhomboid pyrophos, isocyanates, phosphinyl halides, phosphonyl halides, phosphoryl halides. , sulfenyl halides, sulfonyl halides, sulfonic esters and anhydrides. The compounds formed can remain in the treated tertiary amine without interfering with the subsequent generation of the tertiary amine oxide with a peroxide, in particular hydrogen peroxide. However, it is preferable to remove the scavengers and their derivatives that are formed in the reaction with the primary and / or secondary amines from the tertiary amine by distillation, extraction, filtration and / or centrifugation. Any aqueous hydrogen peroxide can be used including those containing 3-100% hydrogen peroxide. Preferably, the hydrogen peroxide is between about 20-70% by weight, most preferably between 45-70% by weight of active hydrogen peroxide. Due to the presence of the solvent in the present process, more concentrated hydrogen peroxide can be used without difficulties in stirring the reaction mixture. A useful amount of hydrogen peroxide must be at least a stoichiometric amount. The scale is typically between about 1-5 moles of hydrogen peroxide, preferably 1-1.5 moles of hydrogen peroxide, per mole of tertiary amine. A highly preferred amount is about 1.05-1.3 moles of hydrogen peroxide, and especially about 1.1-1.2 moles of hydrogen peroxide per mole of tertiary amine. Any excess hydrogen peroxide remaining after the reaction can be destroyed by the addition of a reducing agent, for example, sodium sulfite, sodium thiosulfate and / or sodium thiosulfite. Also useful are peroxide decomposition catalysts such as, for example, those based on platinum or manganese. Additionally, enzymes known in the art, such as those available from Novo Nordisk under the trade name Catazyme, including the 50L product, which have been shown to be efficient in destroying any remaining excess hydrogen peroxide can also be used. The organic solvent used in the present invention can be any organic liquid in which the tertiary amine and the tertiary amine oxide are soluble at the reaction temperature, and which is capable of forming an azeotrope with water. However, to avoid the danger of explosion, this solvent must be substantially inert. In a preferred embodiment of the invention, the solvent is able to keep the reaction mixture fluid and agitated without being used in an amount which would reduce the solids content of the reaction mixture to below about 15% by weight, preferably below about 30% by weight. Excellent results have been achieved at a solids level of approximately 50% by weight. On the basis of cost and availability, as well as effectiveness, the solvents that are preferred to be used in the process are lower alkyl alcohols, such as Ci-s alcohols, and especially C1-4 alcohols containing one or more hydroxyl groups . Exemplary alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-butyl alcohol, 1-hexanol, 2-hexanol, 3- hexanol, 2-methyl-1-propanol, 2-methyl-2-propanol, tert-amyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, neopentyl alcohol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-2-butanol, 1-hexyl alcohol, 2-hexanol, 3-hexanol and the like, as well as various mixtures thereof. Especially preferred solvents include 1-propyl alcohol, 2-propyl alcohol, 1-butanol and 2-butanol. The solvent may optionally contain another solvent such as an aliphatic, cycloaliphatic or aromatic hydrocarbon such as hexane, isohexane, heptane, 2-ethylhexane, octane, isooctane, cyclohexane, cyclooctane, toluene or the like, or a halohydrocarbon such as chlorobenzene, dichlorobenzene, bromobenzene , chlorotoluene, 2,4-dichlorotoluene and the like. Ester solvents are also useful as a co-solvent and exemplary ester solvents include methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, t-butyl acetate, isobutyl acetate , amyl acetate and the propionates, butyrates and corresponding amounts. When the optional cosolvent is used, the amount is generally limited to an amount of up to about 25% (e.g., 1-25%) by weight, based on the weight of the polar solvent. The use of the non-polar solvent reduces the solubility of the tertiary amine and / or the amine oxide in the reaction mixture. The present process also includes the use of a promoter for the oxidation of the tertiary amine. Promoters that are preferred include lower organic acids that are capable of being removed from the reaction mixture by distillation upon completion of oxidation. Preferred acids include: formic acid, acetic acid and propionic acid, with acetic acid being especially preferred. Other organic carboxylic acids such as diethylenetriaminpentaacetic acid or ethylenediaminetetracarboxylic acid are also useful. Other promoters include ammonium carbonate, ammonium bicarbonate and ammonium carbamate, as well as promoter mixtures. Carbon dioxide and aluminum are also effective promoters. The amount of promoter can vary over a large scale. It is required that the amount of promoter in the reaction mixture, in any form that exists, be an amount that causes the reaction to proceed at a faster rate than the rate achieved without the addition of the promoter. In other words, there must be at least a catalytic amount of the promoter. Useful concentrations of the promoter include from about 0.001-10% by weight, based on the weight of the tertiary amine. A preferred concentration is about 0.005-1% by weight. A concentration that is even more preferred is about 0.001-0.8% by weight. When carbon dioxide is added as a promoter, it can be added as a cover over the reaction mixture, or most preferably, the carbon dioxide can be dissolved in the aqueous hydrogen peroxide and / or in the solvent. The reaction can be conducted over a wide range of temperatures. The temperature must be high enough to cause the reaction to proceed at a reasonable speed, but not so high that it leads to the decomposition of the reactants or products. A useful temperature scale is approximately 0 * -140ßC. A temperature scale that is most preferred is approximately 40o-140oC. An even more preferred temperature scale is about 45 ° -130 ° C. Most preferably, the reaction is conducted at about 45 <; > -110oC At this temperature scale the reaction is quite fast and is normally completed in less than about 30 hours, generally less than about 20 hours. Excellent results have been achieved with temperatures of approximately 55 < , -90 ° C. The process of the invention is carried out by adding the aqueous hydrogen peroxide to a solution of the tertiary amine in the solvent containing the promoter. The organic solvent is generally present throughout the reaction, although the amount present at any point during the reaction is quite flexible. The organic solvent can be minimized during the start of the reaction and then added gradually during the course of the reaction to keep the reaction mixture fluid and agitable. Alternatively, the organic solvent may be added completely at the start of the reaction or may be added later during the course of the reaction, as long as the solvent is present for the azeotropic removal of the water from the aqueous hydrogen peroxide. The hydrogen peroxide is preferably added at a controlled rate so that the temperature is preferably maintained within the scales mentioned above. Cooling may be necessary to maintain the temperature within the scale desired. The rate of addition of the hydrogen peroxide is preferably such a rate that a large accumulation of unreacted hydrogen peroxide does not occur at any time. The reaction temperature is maintained within the temperature range until the oxidation has been substantially completed, generally in less than about fifty hours, generally less than about forty hours. When the reaction has been completed, the amine oxide can be immediately recovered by removing the organic solvent and water as an azeotrope. Alternatively, the azeotropic mixture can be removed during the course of the reaction by adding additional solvent to the reaction. The azeotropic mixture is preferably removed with the aid of a vacuum, typically at least 25 mm of mercury, by adding sufficient organic solvent to ensure complete removal of the water from the hydrogen peroxide. The tertiary amine oxide is thus recovered as a solid, in either dihydrate, monohydrate and / or anhydrous form. The recovered amine oxide can be used as it has been collected or its purity can be improved by recrystallizing it one or more times from an organic solvent in which it can be dissolved at a higher temperature and from which it can be precipitated at a temperature more low.

Recrystallization may also be used to reduce the water content of the recovered amine oxide, if desired, using an organic solvent such as ethyl acetate, in which the water is at least partially soluble. For example, if the amine oxide is recovered as a dihydrate, and it is desired to convert it to an oxide containing a lower amount of water, e.g. , to a mixture of dihydrate, monohydrate and anhydrous oxide or to the monohydrated or anhydrous form, the amine oxide can be recrystallized from said organic solvent until the desired degree of dehydration is achieved. The invention is advantageous as a means for preparing free flowing solid tertiary amine oxides which can be used in the preparation of powder compositions, such as mixtures of dry polymer additives, without having been first subjected to further treatments which could increase their cost and / or contaminate them with the materials used in subsequent treatments or with the decomposition products formed during subsequent treatments. The amine oxides formed by the process can be considered all solids, although those of lower molecular weight have melting points that place them at the threshold between solids and liquids at certain temperatures of use; and the amine oxides which are recovered as dihydrates have the additional advantage of being substantially non-hygroscopic, or of having a low hygroscopicity. By low hygroscopicity it is meant that the tertiary amine oxide has an accumulation of water of about 10% less by weight after a 24 hour exposure at 80% relative humidity at 23 ° C. The preferred tertiary amine oxides of the present invention will remain as a solid at room temperature (i.e., 23 ° C) even with a water absorption level of about 10% by weight. These products, whether they are dihydrates, amine oxides that are less than 100% dihydrated, monohydrated or anhydrous amine oxides, have general utility in the same applications as mixed ter-amine oxides which are prepared by conventional techniques, although Their main attractiveness is that they have a shape that makes them very adapted for their incorporation into dry formulations. It should be clear that the present invention provides a process for producing anhydrous amine oxides, and said processes comprise reacting a tertiary amine oxide of the formula wherein R1 and R2 are each independently an alkyl portion of C-30, with aqueous hydrogen peroxide and an amount of an organic carboxylic acid, effective to catalyze the oxidation of the tertiary amine to produce a tertiary amine oxide; wherein said reaction is carried out in a polar hydroxyalkyl solvent; wherein said solvent can form an azeotrope of at least 1% by weight of water; and isolate the tertiary amine oxide by removing the solvent. It should also be clear that at least one of the aforementioned R groups can optionally contain at least a portion -0-, -S-, -SO-, -CO2-, -CO- or -CON-. More specifically, it should be clear that the present invention provides a process for manufacturing solid tertiary amine oxides, said process comprising heating under a nitrogen atmosphere a tertiary amine, isopropyl alcohol, acetic acid and an aqueous hydrogen peroxide at a temperature from about 50 ° C to about 100 ° C until at least about 95% of the tertiary amine oxide has been reacted, and stirring the isopropyl alcohol and water, preferably as an azeotrope, to produce a solid tertiary amine oxide and free flowing. A preferred embodiment of the present invention includes a process for making an oxide of the formula wherein R1 and R2 are each an alkyl portion of C14; and wherein the amine oxide has a loss index at 10% by weight of at least about 120 ° C, when measured at a heating rate of 20 ° C / minute. In another preferred embodiment of the present invention is included a process for making an amine oxide of the formula wherein R1 and R2 are each alkyl portions of Cie-is; and wherein the amine oxide absorbs less than about 10% by weight of water when stored at 23 ° C and 80% relative humidity, and remains solid at 23 ° C. Another preferred embodiment of the present invention includes a process for making an amine oxide of the formula 0 wherein R1 and R2 are each alkyl portions of Q20-22; and wherein the amine oxide absorbs less than about 5% by weight of water when stored at 23 ° C and 80% relative humidity, and remains solid at 23 ° C. All of the cited patents are incorporated herein by way of reference. For those skilled in the art to be able to practice the invention in a better manner, the following examples are given by way of illustration and not by way of limitation.

EXAMPLE 1 A reaction vessel is charged with 62.2 g (0.2 mol) of didecyl ethylamine and 0.3 g of acetic acid in 62.2 g of 2-propanol. The mixture is heated, with stirring, to about 50 ° -55 ° C, followed by the dropwise addition of 16.32 g (0.24 mole) of 50% aqueous hydrogen peroxide over a period of about 60 minutes. The temperature is increased to 60 ° -65 ° C, and the reaction mixture is stirred at that temperature for about 18 hours. Proton NMR analysis shows a conversion of 99 +% of the amine (ie, the level of unreacted tertiary amine was undetectable). The product was recovered by removing the azeotrope of solvent at about 40 ° -50 ° C under a vacuum of about 15-20 mm of mercury, followed by increasing the vacuum to about 1 mm of mercury and increasing the temperature to about 65. -70 ° C for approximately 1 to 4 hours. The analysis showed that the product was anhydrous N, N-didecyl-N-methylamine oxide, a solid having a melting point of about 400-45 ° C. The level of N-nitrosodimethylamine was measured as less than 93 ppb. The recovered yield was 61.44 g (93.3%) as a free flowing white solid. Using the procedure described in Example 1 a variety of tertiary amine oxides were produced. The analysis of some of these illustrative tertiary amine oxides is found in Table 1 TABLE 1 1 The lowest detection limit was 100 ppb. 2 Water absorption was measured at 80% relative humidity and 23 ° C. 3 Measure with a universal TGA V1-5B TA Instruments using a nitrogen purge of 50 mL / min and a temperature scale of 20o-500 ° C at a speed of 20 ° C / min. These results illustrate that solid and free-flowing tertiary amine oxides can be prepared by the process of the present invention. Solid tertiary amine oxides have N-nitrosodimethylamine levels of less than 100 ppb and are obtained in high yields. The amine oxides are useful without further purification.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A process for the production of amine oxides, which is further corrected by the reaction of a reactive amine of the formula: H3 CN-RI R2 in which R1 and R2 are each independently C8-30 alkyl portion, with aqueous hydrogen peroxide and an amount of a carboxylic acid effective to catalyze the oxidation of the tertiary amine to produce an amine oxide; further characterized in that said reaction is carried out in at least one polar hydroxyalkyl solvent; further characterized in that said solvent can form an azeotrope of at least one percent by weight of water; isolating the tertiary amine oxide by removing said solvent.

2. The process according to claim 1, further characterized in that the amine oxide is a solid at 23 ° C after isolation.

3. The process according to claim 1, further characterized in that the amine oxide contains less than about 100 ppb of N-nitrosodimethylamine after isolation.

4. - The method according to claim 1, further characterized in that the solvent is removed with a vacuum.

5. The process according to claim 1, further characterized in that the amine oxide has the formula: wherein R * and R2 are each alkyl portions of Cie-is; and wherein the amine oxide absorbs less than about 10% by weight of water when stored at 23 ° C and 80% relative humidity, and remains as a solid at 23 ° C.

6. The process according to claim 1, further characterized in that the amine oxide has the formula: wherein R1 and R2 are each alkyl portions of Q20-22; and wherein the amine oxide absorbs less than about 5% by weight of water when stored at 23 ° C and 80% relative humidity, and remains as a solid at 23 ° C.

7. The process according to claim 1, further characterized in that the amine oxide has the formula: wherein R1 and R2 are each an alkyl portion of C14; and wherein the amine oxide has a loss index at 10% by weight of at least about 120 ° C, when measured at a heating rate of 20 ° C / minute.

8. The process according to claim 1, further characterized in that the amine oxide has the formula: wherein R1 and R2 are each an alkyl portion of Ciß-is; and wherein the amine oxide has a loss rate at 10% by weight of at least about 145"C, when measured at a heating rate of 20 ° C / minute. claim 1, further characterized in that the amine oxide has the formula: 0 H3C-N-RI R2 wherein R1 and R2 are each an alkyl portion of C20-22; and wherein the amine oxide has a loss rate at 10% by weight of at least about 220 ° C, when measured at a heating rate of 20 ° C / minute. 10. The process according to claim 1, further characterized in that the polar hydroxyalkyl solvent is selected from the group consisting of Ci-β alcohols containing one or more hydroxyl groups. 11. A process for manufacturing solid tertiary amine oxides, said process comprising heating under a nitrogen atmosphere a tertiary amine, a polar hydroxyalkyl solvent, an organic acid and aqueous hydrogen peroxide at a temperature of between about 50 ° C and about 100 ° C. ° C until about 95% of the tertiary amine oxide has reacted, and remove the polar hydroxyalkyl solvent, the organic acid and water as an azeotrope to produce a solid, free-flowing tertiary amine oxide. 12. The process according to claim 11, further characterized in that the tertiary amine oxide comprises at least 90% tertiary amine oxide. 13. The method according to claim 11, further characterized in that the polar hydroxyalkyl solvent is selected from the group consisting of Ci-β alcohols containing one or more hydroxyl groups. 14. The process according to claim 11, further characterized in that the organic acid is at least one acid selected from the group consisting of acetic acid, formic acid and propionic acid. 15. The process according to claim 11, further characterized in that the aqueous hydrogen peroxide contains between about 20% to 90% by weight of hydrogen peroxide. 16. The process according to claim 11, further characterized in that the molar ratio of the tertiary amine to hydrogen peroxide is between about 1: 1 to about 1: 2. 17. The process according to claim 11, further characterized in that said process produces less than about 250 parts per billion of a nitrosamine based on the weight of the tertiary amine oxide. 18. The process according to claim 11, further characterized in that the weight ratio of the tertiary amine to the organic acid is between about 50: 1 to about 500: 1. 1

9. The process according to claim 11, further characterized in that the tertiary amine is at least one amine of the formula: wherein R1 and R2 are each independently an alkyl portion of C1-30, and wherein at least one of R1 and R2 may optionally contain at least a portion -0-, -S-, -SO-, -CO2-, -CO- or -CON-. 20. The process according to claim 19, further characterized in that the weight ratio of the tertiary amine to the organic acid is between about 50: 1 to about 500: 1. 21. A process for manufacturing solid tertiary amine oxides, said process comprising heating under a nitrogen atmosphere a tertiary amine, isopropyl alcohol, acetic acid and aqueous hydrogen peroxide at a temperature between about 50 ° C and about 100 ° C until that approximately 95% of the tertiary amine oxide has reacted, and remove the isopropyl alcohol and water to produce a solid, free-flowing tertiary amine oxide. 22. The process according to claim 21, further characterized in that the tertiary amine is at least one tertiary amine selected from the group consisting of didecylmethylamine, dicocoalkylmethylamine, ditallow alkylmethylamine, diethylsilylmethylamine and didocosanylmethylamine.