MX2007000298A

MX2007000298A - Composition comprising choline hydroxide and process for preparing the same.

Info

Publication number: MX2007000298A
Application number: MX2007000298A
Authority: MX
Inventors: Reinhard Broucek; Hendrikus A Workel; Johannes Wilhelmus Franc Seetz; Gerrit Jan Oudendijk
Original assignee: Akzo Nobel Nv
Priority date: 2004-07-09
Filing date: 2005-07-04
Publication date: 2007-04-02
Also published as: RU2007104939A; WO2006005692A1; CA2573213A1; US20070193708A1; EP1781594A1; CN1984875A; JP2008505867A

Abstract

The present invention relates to a composition comprising choline hydroxide, a solvent, and one or more stabilizers selected from the group consisting of a hydride and choline sulfite.

Description

COMPOSITION THAT INCLUDES HIDROXIDE OF HILL AND PROCEDURE TO PREPARE DESCRIPTIVE MEMORY The present invention relates to a composition comprising choline hydroxide, a stabilizer and a solvent, to a process for preparing the composition, and to the use thereof. Choline hydroxide, also known as choline base or (2-hydroxyethyl) thmethylammonium hydroxide, is a well-known organic base which is suitable for many uses. However, choline hydroxide compositions, especially in water, undergo a gradual decomposition process. It is believed that the main reason for this decomposition is the tendency of the choline base to attack itself, resulting in the products of this decomposition reacting additionally. The underlying chemistry of this degradation is quite complex and not yet fully understood, but it results in choline-based solutions turning from brown to black during longer storage and developing precipitates. It is known that to avoid this decomposition a stabilizer is added to the aqueous compositions of choline hydroxide, which allows a longer storage of the choline-based solution as a clear solution. US 4,294,911 describes the addition of a stabilizing concentration of a sulfite to an aqueous composition of choline hydroxide. Sulfite is usually added as the sodium sulfite salt that is cheap and readily available. A disadvantage of using sodium sulphite is that solutions based on concentrated choline continue to darken in a relatively short period, it is believed that the reason for this is due to a low solubility of sodium sulfite in solutions based on concentrated choline . For example, in an aqueous solution based on choline at 45% by weight, less than 0.5% by weight of sodium sulfite is soluble. There are more soluble sulfites, but these are much more expensive and / or are not readily available. US 4,686,002 describes the addition of a stabilizing concentration of formaldehyde to the aqueous composition of choline hydroxide. Formaldehydes have been discarded from many applications due to environmental issues. The aim of the present invention is to provide a stabilized composition of choline hydroxide which is free from the above drawbacks. This object is achieved by providing a composition comprising choline hydroxide, a solvent, and one or more stabilizers selected from the group consisting of a hydride and choline sulphite.

The stabilizer that is used in the composition of the present invention causes the composition to retain its white color for a longer period compared to sodium sulfite. The stabilizers of the present invention also have the advantage that they generally introduce less salt into the composition. composition, a lower amount of hydride is generally required to avoid darkening the composition compared to conventional compositions comprising a sodium sulfite salt, and choline sulfite does not introduce any salt into the composition. It should be noted that in the US 6,065,424 describes an aqueous composition comprising a choline hydroxide or a borohydride salt. However, this publication does not disclose compositions of a choline hydroxide and a borohydride salt. This publication also does not refer to choline hydroxide stabilizing solutions, even to the knowledge of the bed that salts bo Rohydride can stabilize choline hydroxide In a preferred embodiment of the composition according to the present invention, the solvent is water or an alcohol, more preferably water or methanol, preferably water. However, a mixture of these solvents may also be used. In another preferred embodiment the invention relates to a composition comprising choline hydroxide and a borohydride compound, wherein the amount of the borohydride compound is smaller than the amount of choline hydroxide in a base by weight. In another embodiment, the composition according to the invention comprises from 10 to 60% by weight of choline hydroxide, based on the total weight of the composition. In a more preferred embodiment the composition comprises from 20 to 55% by weight of choline hydroxide, based on the total weight of the composition, and in a more preferred embodiment comprises from 30 to 50% by weight. In another preferred embodiment the composition according to the invention comprises a hydride as a stabilizer in an amount of 1 ppm to 1,000 ppm, preferably 10 ppm to 500 ppm, and more preferably 50 ppm to 200 ppm. The stabilizer is choline sulphite, the composition according to the invention comprises from 0.1 to 19% by weight, based on the total weight of the composition, from 0.2 to 5% by weight preferences, and more preferably from 0.5 to 1% in weight of choline sulphite. Compositions comprising these amounts of stabilizer reveal greater color stability than conventional choline-based compositions containing sodium sulfite as a stabilizer. The present invention also relates to a masterbatch comprising from 10 to 60% by weight of choline hydroxide, from 5 to 20% by weight of one or more stabilizers selected from the group consisting of a hydride and choline sulphite, with the remaining part being solvent based on the total weight of choline hydroxide, stabilizer and solvent. Said masterbatch, which normally comprises a large amount of stabilizer can be added to a solution of choline hydroxide in a desired amount to stabilize the solution. Said master batches preferably comprise from 8 to 15% by weight of stabilizer and more preferably from 10 to 12% by weight, based on the total weight of the masterbatch. The stabilizer of the present invention is selected from the group consisting of hydrides and choline sulphite. The hydride is generally a strong reducing agent and can be any hydride known to those skilled in the art. Suitable examples of hydrides are lithium hydrides, aluminum hydrides and borohydrides. Preferred hydrides are borohydrides. In this application the term "borohydride" refers to any compound or mixture of compounds, comprising a molecule of boron and hydrogen, also known as hydroborons, with the formula BxHy, x and y are integers >; 0, such as B2H6, (borohetane), B2H10 (borobutane), B5H9, and B10H1 (borodecane), and anions derived therefrom such as BH4. Gaseous borohydrides are less preferable, as they are difficult to handle and can pose safety risks. Preferred borohydrides comprise one or more anions derived from borohydride. The preferred borohydride is a salt of BH "and the alkali metal borohydride salts are particularly preferred.A preferred alkali metal borohydride salt due to its commercial availability and the fact that it is relatively safe to handle, handle and use, is sodium borohydride (NaBH4).

In an alternative preferred embodiment according to the invention, the composition comprises a hydride, in particular a borohydride compound, which is fixed to a polymer carrier. The use of said borohydride compound has the advantage that the borohydride stabilizer can be easily removed from the choline base solution when desired, for example, when the choline base solution is used in an application where the borohydride or inorganic counterion have a determining effect. In another preferred embodiment the composition comprises one or more additional stabilizing compounds. Suitable examples of said stabilizing compounds include sulfites, formaldehyde, hydroxylamines, derivatives and mixtures thereof, preferably, the second stabilizing compound is a sulfite or a sulfite derivative. Sulfite derivatives include, for example, dithionites. In a more preferred embodiment sulfite is sodium sulfite. In another more preferred embodiment, two or more additional stabilizer compounds are used. The advantages of the stabilizer in particular of the borohydrides are its reducing power and its compatibility with the choline base production processes. Due to its reducing power the choline base solution is clear and pain white paper. The hydrides, and in particular the borohydride compounds, can even be added to a choline-based mixture that is already yellow and still provides a clear, white solution.

Another advantage of the stabilizers of the invention is that they are stable under strongly alkaline conditions. This means that the concentration of the stabilizer in the choline base can be increased to sufficiently high amounts to combine the desired properties of both the choline hydroxide and the stabilizer. This is particularly advantageous when borohydrides are used as a stabilizer. The process also relates to a process for preparing the composition according to any of claims 1 to 5, by combining one or more stabilizers selected from the group consisting of a choline hydride and sulfite with a choline hydroxide solution. The fact that the stabilizer of the invention is compatible with the production process of the choline base makes it possible to add the stabilizer to the starting materials and / or to the reaction mixture in the process to produce choline hydroxide. Therefore, the present invention also relates to a process for preparing the composition of the invention, comprising the steps of reacting ethylene oxide with trimethylamine in the presence of one or more stabilizers, selected from the group consisting of a hydride and choline sulphite, said stabilizer is added to the ethylene oxide, the trimethylamine and / or the reaction mixture. This process for preparing the choline base is generally carried out by reacting ethylene oxide with tpmethylamine in an inert atmosphere at a temperature of 0 to 70 ° C. If choline sulphite is used as a stabilizer, the preparation of the sulfite of hill in situ by submitting the choline hydroxide solution produced by reacting ethylene oxide and tmethylamine to sulfur dioxide The resulting amount of choline sulfite in the choline hydroxide solution will depend on the period during which the choline hydroxide solution is subject to sulfur dioxide. By submitting the choline hydroxide solution to the sulfur dioxide for some time, the resulting amount of choline sulfite can be established as desired. In a preferred embodiment of the process for preparing the choline base, the stabilizer, in particular borohydride, it is used in an amount as 1 -1 000 ppm, preferably 10-500 pp m, more preferably 50-200 ppm of borohydride which is present in the total weight of the solution of the final product In the case that it is desired to prepare a master batch according to the invention with the above procedures, the stabilizer is used in an amount such as 5 to 20% by weight, preferably 8 to 15% by weight, and more preferably 10 to 12% by weight which is present in the total weight of the product solution. In an alternative preferred embodiment of the process the choline base is prepared at a temperature between 10 and 50 ° C and an inert atmosphere is created by flooding the reactor and the solution with an inert gas, while maintaining a safety pressure of inert gas, usually nitrogen, during the reaction step. In a more preferred embodiment of the method, the temperature is between 15 and 45 ° C, more preferably it is a temperature of about room temperature. The compositions according to the present invention are suitable for many applications. As already indicated above, since the amount of the stabilizer in a choline base can be relatively high, the compositions can also be used in applications in which the stabilizer is also active. With respect to this, the stabilizers of the invention, and in particular borohydride, are particularly suitable for use in the production and bleaching of paper. Accordingly, a method for bleaching paper pulp is also covered by the present application. In this method the paper pulp is contacted with the compositions according to the present invention. Aqueous compositions comprising a borohydride salt are known for bleaching paper and are described, for example, in WO 88/10334. However, aqueous solutions comprising choline hydroxide and a borohydride salt for paper bleaching are not described for this use. In addition, known borohydride solutions that are used in applications in which borohydride is active, are often encaustic-borohydride solutions, which often make them less suitable for applications that are not compatible with a caustic solution, such as the production of borohydride. paper. The present invention will be further illustrated with the following examples: EXAMPLE OF PREPARATION A A solution based on choline in water is prepared in a one liter pressure autoclave by reacting 116 g of ethylene oxide with a solution of 150 g of trimethylamine in 417 g of water. When using a cooling jacket the temperature during the reaction is maintained between 15 and 45 ° C. Before the start the reactor is flooded with nitrogen and a safety pressure of 2-3 bar of nitrogen is maintained during the ethoxylation step. The resulting solution of 45% by weight of choline base in water is used in the following Examples 1 to 3.

EXAMPLE OF PREPARATION B A solution of choline sulphite is prepared by adding gaseous sulfur dioxide in a stoichiometric amount to the aqueous solution of choline base I 45% by weight of preparation example A. The resulting solution to 53% by weight of choline sulphite is used in the following examples 1, 2, 5 and 6.

EXAMPLE OF PREPARATION C A solution of sodium borohydride in choline base is prepared by adding solid sodium borohydride to an aqueous solution based on choline at 45% by weight of Preparation Example A, until a concentration of 12% by weight of borohydride is reached. The resulting aqueous composition is used in the following preparation example D.

EXAMPLE OF PREPARATION D A solution based on choline in water is made in a one liter pressure autoclave by reacting 116 g of ethylene oxide and 150 g of trimethylamine in 417 g of water. When using a cooling jacket the temperature during the reaction is maintained between 15 and 45 ° C. Before starting the reactor, it is flooded with nitrogen and a safety pressure of 2-3 bar is maintained during the ethoxylation step. Before starting the reaction, 0.85 g of the borohydride solution described in example C are added. The resulting aqueous composition is used in the following examples 4 and 5.

COMPARATIVE EXAMPLE 1 Two samples of 110 g of the choline base solution of preparation example A were placed in 100 ml sample bottles under a flood with nitrogen. The choline sulphite solution of Preparation Example B was added until the total choline sulphite concentration in the sample of 0.2% by weight was reached. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions were slightly yellow but still clear (ie free of precipitates).

COMPARATIVE EXAMPLE 2 Two samples of 110 g of the choline base solution of preparation example A were placed in 100 ml sample bottles under a flood with nitrogen. The choline sulphite solution of Preparation Example B was added until the total concentration of choline sulphite in the sample was 0.4% by weight. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions were slightly yellow but still clear.

COMPARATIVE EXAMPLE 3 Two samples of 1 10g of the choline-base solution of preparation example A were introduced into 100 ml sample bottles under a flood with nitrogen. It was added to formaldehyde until the total concentration of formaldehyde in the sample was 0.4% by weight. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions had darkened and a layer of brown precipitates had formed on the bottom of the sample bottles.

EXAMPLE 4 Two samples of 110 of the choline base solution of preparation example D were introduced into 100 ml sample bottles under nitrogen flooding. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions remained clear and the paper white.

EXAMPLE 5 Two samples of 110 g of the choline base solution of preparation example D were introduced into 100 ml sample bottles under nitrogen flooding. The choline sulphite solution of Preparation Example B was added until the total concentration of choline sulfite in both samples was 0.4% by weight. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions remained clear and the paper white.

EXAMPLE 6 Two samples of 110 g of the choline base solution of preparation example D were introduced into 100 ml sample bottles under nitrogen flooding. The choline sulphite solution of Preparation Example B was added until the total concentration of choline sulphite in both samples was 2.6% by weight. The sample bottles were closed and stored under ambient conditions. After 4 months the solutions remained clear and the paper white.

EXAMPLE 7 Two samples of 110 g of the choline base solution of preparation example B were introduced into 100 ml sample bottles under nitrogen flooding. Sodium sulfite was added until the total concentration of sodium sulfite in both samples was 0.5% by weight. The bottles were sampled and stored under ambient conditions. After 4 months the solutions remained clear and the paper white, but a white layer of undissolved sodium sulphite had formed on the bottom of the sample bottles.

NOVELTY OF THE INVENTION CLAIMS 1 - . 1 - A composition comprising a colloidal hydroxide, a solvent, and one or more stabilizers selected from the group consisting of a choline hydride and sulphyl 2 - The composition according to claim 1, further characterized in that the stabilizer is a borohydride salt of alkali metal, more preferably a sodium borohydride salt 3 - The composition according to any of claims 1 and 2, further characterized in that the amount of colloidal hydroxide is from 10 to 60% by weight based on the total weight of the composition, preferably 40 to 50% by weight 4 - The composition according to any of the preceding claims, further characterized in that the amount of stabilizer is between 1 and 500 ppm, preferably between 50 and 200 ppm 5 - composition according to any of the preceding claims, further characterized in that it comprises one or more additional stabilizing compounds In addition, the additional stabilizing compound is preferably sodium sulfite 6 - A masterbatch comprising from 10 to 60% by weight of choline hydroxide, from 5 to 20% by weight of one or more stabilizers

Claims

selected from the group consisting of a choline hydride and sulphite, and the remaining part is a solvent, based on the total weight of choline hydroxide, stabilizer and solvent. 7. A process for preparing the composition according to any of claims 1 to 5, combining one or more stabilizers selected from the group consisting of a choline hydride and sulphite, with a choline hydroxide solution. 8. A process for preparing the composition according to any of claims 1 to 5, comprising the steps of reacting ethylene oxide with trimethylamine in the presence of one or more stabilizers selected from the group consisting of a hydride and sulfite of choline, said stabilizer is added to the ethylene oxide, the trimethylamine and / or the reaction mixture. 9. The process according to any of claims 7 and 8, further characterized in that the stabilizer is an alkali metal borohydride salt, preferably sodium borohydride salt. 10. The use of the composition claimed in any of claims 1 to 5, in the production of paper.