MXPA99011616A - Hydrophobically modified anionic cellulose ethers - Google Patents

Abstract

La presente invención se refiere a unéter de celulosa aniónico hidrófobamente modificado obtenible mediante un procedimiento que comprende hacer reaccionar una celulosa de metal alcalino, con por lo menos tres reactivos de alquilación, A, B y C;el reactivo A se selecciona del grupo deácidos halogenoacéticos, halogenoacetatos de metal alcalino, vinil sulfonatos de metal alcalino yácido vinil sulfónico;el reactivo B tiene la fórmula Rl-(OCH2CH(R2))n-P, en donde R1 representa un grupo de C2-C7, R2 es hidrógeno o un grupo metilo, n es de 0 a 2, y P representa un grupo deéter glicidilico, un grupo deéter 3-halógeno-2-hidroxipropilico, un grupo 1,2-epoxi, o un halogenuro, y el reactivo C tiene la fórmula R3-(OCH2CH(R2))m-P , en donde R3 representa un grupo de C8-C30, m es de 0 a 10, y R 2 y P tienen el significado descrito anteriormente.

Description

HYDROPHOBLY MODIFIED ANIONIC CELLULOSE ETHERIES DESCRIPTIVE MEMORY The present invention relates to a hydrophobically modified anionic cellulose ether, such as hydrophobically modified carboxymethyl cellulose. Methods for preparing polysaccharides such as cellulose, starch and guar gum, which have hydrophobic substituents are known in the art. For example, EP-A-0384167 discloses a suspension process, using a diluent system, to prepare water-soluble polysaccharides, in particular hydroxyethylcellulose (HEC) derivatives, which contain alkylaryl substituents having at least about 10 carbon atoms. carbon, for use in latex compositions. The process comprises reacting a substituted polysaccharide with ether, with a hydrophobic alkylaryl-containing compound. It is mentioned that as a result of reacting a polysaccharide ether with a hydrophobic alkylaryl, substitution with ether in the polysaccharide provides an increase in hydrophobic substitution comparatively with the unsubstituted saccharide. Examples 35 and 36 of EP-A-0384167 show that when nonylphenyl glycidyl ether is used, a higher alkylation efficiency is observed with polysaccharides having a higher molar substitution value (MS) of ethylene oxide (as hydroxyethyl). MS is defined as the average mole of one substituent per mole of repeating sugar unit. With an MS of ethylene oxide of 3.5, a hydrophobic MS of 0.059 was obtained with an efficiency of 24%, while with an MS of ethylene oxide of 2.3, a hydrophobic MS of 0.025 was observed with an efficiency of 10%. Therefore, the hydrophobic substitution efficiency obtained is low. In this way, a disadvantage of this method is that the hydrophobic substitution proceeds with a low efficiency, resulting in waste of chemicals and charge to the environment. A further drawback is that the efficiency with which the hydrophobic groups are incorporated depends on the presence of hydroxyethyl groups per se, and only increases with an increasing number of said groups. This is due to the fact that the hydroxyalkyl substituents are more prone to undergo alkylation than the hydroxyl groups in the repeating sugar unit. Methods for preparing hydrophobically derived polysaccharides are also known from EP-A-0566911 and EP-A-037915. The process of EP-A-0566911 comprises reacting a polysaccharide with an alkyl halide, an alkylene oxide or a chloroacetic acid in the presence of an alkali, by reacting the modified polysaccharide with a hydrophobic alkyl or alkylaryl reactant having 8 to 24 carbon atoms and containing a nucleophilic reactive group selected from a glycidyl ether and an isocyanate, to produce a water-soluble hydrophobically modified polysaccharide. This hydrophobically modified polysaccharide is subsequently depolymerized by reaction with hydrogen peroxide at the desired level. The following polysaccharides have been hydrophobically modified: polyvinyl alcohol, carboxymethyl hydroxypropyl starch, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxypropyl guar, carboxymethyl hydroxyethyl cellulose, and HEC. EP-A-0566911 describes, among other things, a suspension process in which stearyl isocyanate and nonylphenyl glycidyl ether were used. The HEC was modified using hexadecyl glycidyl ether, and the percentage by weight of hydrophobic compound in the product (depolymerized) was 0.4 to 1.4% (example 1). This corresponds to a low hydrophobic MS of approximately 0.005 and 0.02, respectively. A similarly low hydrophobic MS of about 0.01 was calculated for carboxymethyl hydroxyethyl cellulose (CMHEC) derived with hexadecyl glycidyl ether (Table 4, No. 13). The hydrophobic substitution efficiencies could not be calculated based on the information given in this publication, but it is estimated that they are also low. EP-A-0307915 describes a process for preparing hydrosoluble hydrophobic CMHEC modified with an alkyl, a-hydroxyalkyl or acyl group having from 8 to 25 carbon atoms. In the preparation example, the hexadecyl hydrophobe represents only 0.7 weight percent of the cellulose. A hydrophobic substitution efficiency of 6.7% was calculated. The suspension process is preferably carried out by first hydroxyethylating the cellulose, then joining the hydrophobe, and finally carboxymethylating the product. The processes of EP-A-0566911 and EP-A-0307915 have the same disadvantages mentioned above in EP-A-0384167, that is, a low hydrophobic substitution efficiency and the incorporation of hydroxyethyl groups. In particular, these publications do not disclose a process for preparing hydrophobically modified anionic cellulose ethers, for example, hydrophobically modified carboxymethyl cellulose (CMC) which does not possess a hydroxyalkyl group. Several other methods have been described in the art, in particular with respect to the preparation of hydrophobically modified nonionic cellulose ethers; see, for example, US 4228277, US 4243802, EP-A-0390240, US 5120838, US 5124445, EP-A-0362769, EP-A-0471866 and US 5504123. In US 5566760, a process is described for the preparation of hydrophobically modified guar derivatives. Finally, EP-A-0189935 discloses hydrosoluble polysaccharides containing quaternary nitrogen hydrophobically derivatives, in particular HEC derivatives. Only quaternary ammonium cellulose derivatives are described. The HEC is hydrophobically modified by alkylation with a quaternary nitrogen containing compound, such as 3-chloro-2-hydroxypropyl trimethyl ammonium chloride, and a hydrophobe of alkyl halide, for example dodecyl bromide. In run 35, a low hydrophobic MS of 0.016 was obtained. A hydrophobic substitution efficiency of 13% was calculated. However, it is not always convenient to incorporate a quaternary ammonium group in a hydrophobically modified polysaccharide. The prior art mentioned above does not disclose hydrophobically modified anionic cellulose ethers, in particular hydrophobically modified CMC, which do not possess a hydroxyalkyl group. The present invention provides such ethers and an inexpensive process for preparing them. The hydrophobically modified anionic cellulose ether according to the present invention is obtained by a process comprising reacting an alkali metal cellulose with at least three alkylating reagents, A, B and C, one or more reagents A being selected from the group of halogenoacetic acids, alkali metal halogenoacetates, alkali metal vinyl sulfonates and vinyl sulfonic acid, one or more reagents B having the formula R1- (OCH2CH (R2)) n- P, wherein R1 represents a group of C2 -C7, R2 is hydrogen or a methyl group, n is from 0 to 2, and P represents a glycidyl ether group, a 3-halogeno-2-hydroxypropyl ether group, a 1,2-epoxy group, or a haiogenide , and one or more reagents C having the formula R3- (OCH2CH (R2)) mP, wherein R3 represents a group of C8-C30, m is from 0 to 10, and R2 and P have the meaning described above. The hydrophobically modified anionic cellulose ethers according to the present invention can be prepared from easily obtainable cellulose starting materials. These materials include cotton lint and highly purified alpha wood pulp. Typically, the cellulose is reacted with an aqueous solution of an alkali metal hydroxide to prepare the alkali metal cellulose. Suitable alkali metal hydroxides include sodium hydroxide, potassium hydroxide and lithium hydroxide, with sodium hydroxide being preferred. Reagents A suitable for the process of the present invention include chloroacetic acid, sodium chloroacetate and sodium vinyl sulfonate. A mixture of, for example, chloroacetic acid and sodium vinyl sulfonate can also be used, and this results in the preparation of a hydrophobically modified carboxymethyl sulfoethyl cellulose. It is preferred that reagent A consists essentially of chloroacetic acid. Suitable reagents B include benzyl chloride, allyl chloride, chloroethyl butyl ether, ethyl glycidyl ether, butyl glycidyl ether, butoxyethyl glycidyl ether, tert-butyl glycidyl ether, isobutyl glycidyl ether, allyl glycidyl ether, propyl glycidyl ether, isopropyl glycidyl ether , benzyl glycidyl ether, and benzyl halides. Preferably, P is a glycidyl ether group. It is also preferred that R2 is hydrogen. In addition, it is preferred that n is equal to 0. Preferred alkylation reagents B are butyl glycidyl ether and benzyl chloride. Reagent C contains the hydrophobic group. The group R3 preferably has from 8 to 22, more preferably from 12 to 22, carbon atoms. Reagents C suitable for the process of the invention include compounds wherein R3 represents a nonylphenyl group, 2-ethylhexyl, dodecyl, tetradecyl, hexadecyl, octadecyl or hexacosyl. R3 can be derived from naturally occurring fatty acids, such as coconut, tallow and hydrogenated tallow fatty acid. Reagent C may optionally contain 1 or more oxygen atoms in the form of ethyloxy or propyloxy groups. Typical examples thereof are tetradecyl-penta-oxyethyl glycidyl ether, hexadecyl-bis-oxyethyl glycidyl ether and octadecyl-bis-oxyethyl glycidyl ether. Preferred alkylating reagents C are dodecyl glycidyl ether, tetradecyl glycidyl ether, hexadecyl glycidyl ether, octadecyl glycidyl ether, dodecyl-bis-oxyethyl glycidyl ether, tetradecyl-bis-oxyethyl glycidyl ether, hexadecyl-bis-oxyethyl glycidyl ether, octadecyl ether, bis-oxyethyl glycidyl, tetradecyl-penta-oxyethyl glycidyl ether, and mixtures thereof. Preferably, m is from 0 to 5 and R2 is hydrogen. It will be noted that for n = 1-2 and m = 1-10, n and m are average numbers. The process of the present invention can be carried out at any suitable reaction temperature, typically between 20 and 125 ° C, and preferably at about 55 to 105 ° C, for a sufficient time to provide the desired level of hydrophobic substitution, typically around 1 to 24 hours, or more. The reaction can be carried out in a relatively large amount of diluent, or with a minimum amount of diluent, as desired, that is, using so-called suspended or dry processes. In this specification, the term suspension process means a process wherein the weight ratio of liquid medium: cellulose is greater than 10, while a dry process means a process wherein the weight ratio of liquid medium: cellulose is equal a, or less than, 10, preferably less than 5, more preferably less than 3. Typically, a dry process is carried out in a high efficiency, intensive mixer, for example, a grate mixer. Suitable diluents include ethanol, isopropyl alcohol, tert-butyl alcohol, acetone, water, methyl ethyl ketone, and mixtures thereof. The reaction can be carried out in any reactor or reaction vessel. The vessel or reactor is suitably equipped with a mixing agitator or gear, a nitrogen inlet pipe, a condenser, and heating means. A particularly suitable reactor is a Drais® or Lódige® reactor. The molar ratio of alkali metal hydroxide per repeating unit of sugar may vary, depending on the alkylating agents used. Typically, a molar ratio of between 0.001 and 5 is used. Depending on the nature of the alkylation reagents used, more alkali metal hydroxide is added. For example, when chlorinated alkylating agents, for example, chloroacetic acid, are used, an additional molar equivalent of hydroxide is required. When a glycidyl ether is used, a catalytic amount of alkali metal hydroxide is sufficient. Many polysaccharides when they come in contact with any base are easily degraded by oxygen. Accordingly, it is preferred to exclude oxygen from the reaction vessel during the time that the alkali metal hydroxide is present. The reaction is suitably carried out in an atmosphere of an inert gas, preferably nitrogen. After the reaction of the cellulose with a suitable amount of an aqueous solution of an alkali metal hydroxide, the alkali metal cellulose can be reacted first with the alkylation reagent A, followed by reaction with the alkylation reagent B, and then C, or with a mixture of B and C, at a suitable temperature and for a sufficient time to provide the desired level of hydrophobic substitution. Alternatively, the alkylation reagent B followed by C or a mixture of B and C can be added first, after which the alkylating reagent A is allowed to react., or the alkali metal cellulose can be reacted simultaneously with the alkylating reagents A, B and C. It was found that if the alkali metal cellulose is first reacted with a mixture of B and C, and then with A, the The first reaction step can be carried out in the presence of only water. An additional alternative reaction route is to first add a small amount of reagent A, then reagents B and C, either sequentially or simultaneously, and finally the remainder of reagent A. A preferred embodiment of the process of the invention is the reaction of the alkali metal cellulose first with a mixture of alkylation reagents B and C, and then with reagent A, in particular when chloroacetic acid is used. It is preferred to carry out the process of the invention by the so-called dry process using a minimum amount of a suitable diluent, in particular water, ie barely enough to allow the polysaccharide to swell while preventing dissolution. The cellulose, in the form of fibers, fluffs or powder, is allowed to react with an aqueous solution of an alkali metal hydroxide, ie the so-called alkalinization, and the obtained alkali metal cellulose is reacted with reagents A, B and C as described above, wherein the temperature is gradually increased from about 10 to about 105 ° C. The reagents can be added pure or as a solution in a suitable diluent, for example, a solution of chloroacetic acid in ethanol can conveniently be used. A particularly preferred process according to the present invention comprises a dry process in which reagent B, followed by C, or a mixture of B and C, is reacted with alkali metal cellulose in the presence of water, before its reaction with reagent A. Typically, the amount of water present during alkylation is between 2 and 12 moles per mole of cellulose. Preferably, an amount of 3.5 to 10 moles / mol of cellulose is used. The reaction with the reagent A is preferably carried out in an aqueous alcohol medium, in particular, it is carried out in the presence of isopropanol or ethanol, water being derived from the alkalization. The person skilled in the art will be able to easily select suitable molar ratios of the reactants per repetitive unit of sugar for the process of the invention. For reagent A, a molar ratio between 0.3 and 3.5 is adequate. A ratio between 0.5 and 2.5 is preferred. For reactant B, a molar ratio between 0.02 and 1.5 is adequate, a ratio between 0.05 and 1 being preferred. For reagent C, a molar ratio of between 0.001 and 1 is adequate, preferably a ratio between 0.005 and 0.5. In another embodiment of the process of the present invention, a fourth alkylation reagent, ie, a quaternary ammonium compound, is used. Polysaccharides containing hydrophobically modified quaternary ammonium are known in the art, for example from EP-A-0189935. Typically, compound D is a 3-trialkylammonium-1,2-epoxypropane haiogenide, wherein each of the alkyl groups is a methyl, ethyl, benzyl or long chain alkyl group. Preferably, 3-trimethylammonium-1,2-epoxypropane chloride or 1-chloro-2-hydroxy-3-trimethylammoniopropane chloride is used.

The hydrophobically modified celluloses of the present invention can be used, for example, in anti-sedimentation, associative thickening and in foam, emulsion and suspension stabilizations. These celluloses are important for several industries that include the drilling industry and paints, for example, latex compositions; cosmetics such as shampoos; biomedicine, such as in oral care, including toothpaste or in pharmaceutical compositions that include synchronized release formulations or controlled release formulations; detergents, such as in surface cleaning or laundry compositions; release of dirt; several other synchronized release applications including pesticides; and other areas in which a rheology modifier, thickener, emulsifier, stabilizer or protective colloid is desired. The process defined in claim 1 can also be used for the preparation of hydrophobically modified anionic polysaccharide ethers derived from hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, guar gum and starch. Using a combination of reagents B and C as described herein, starch, guar gum, ethyl hydroxyethyl cellulose, hydroxyethyl cellulose, and hydrophobically modified nonionic cellulose can be prepared. The invention is illustrated by the following examples.

EXPERIMENTS Materials: Cellulose fluff (milled at 0.5 mm), for example, Buckeye N-butyl glycidyl ether, 95%, eg, CFZ Dodecyl ether / tetracyclyl glycidyl, for example, from Aldrich Ether Nafol®1214-2EO glycidyl: a mixture of dodecyl-bis-oxyethyl glycidyl ether and tetradecyl-bis-oxyethyl glycidyl ether, 85% Nafol®1214, for example, Condea isopropyl alcohol, 99.5%, for example, Fluka Ethanol, 95%, for example, Baker sodium hydroxide, 50% in water, for example, Acros Chloroacetic acid, 99%, for example, from Akzo Nobel Acetic acid, 99.8%, for example, Baker Benzyl chloride, 99%, for example, Fluka Naphol®1214-2EO glycidyl ether was prepared according to the method described in EP-A-0390240 in Example A, starting with a mixture of 1-dodecanol and 1-tetradecanol, ie Nafol®1214. Following the same method, tetradecyl-penta-oxyethyl glycidyl ether, a mixture of hexadecyl- and octadecyl-bis-oxyethyl glycidyl ether and a mixture of dodecyl- and tetradecyl-bis-oxy-glycidyl ether were prepared from the corresponding mixture of alcohols.

The reactions were carried out in a Drais® turbulent mixing reactor, type TR2.5. The blades were shaken at 180 rpm. The reactor was heated by a Thermomix UB water / oil bath. Epoxide conversions were determined by titration using an Impulsomat Methrom 614 in combination with a Methrom 625 dosimeter or an Methrom E536 potentiometer. The MS and DS values were determined using a Bruker 300 MHz NMR spectrometer, as specified by F. Cheng et al. In the Journal of Applied Polvmer Science. Vol. 61, 1831-1838 (1996). CM means carboxymethyl, BGE means n-butyl glycidyl ether, BEGE means butyloxyethyl glycidyl ether, and FAE means fatty alkyl ether (ethoxylated). The efficiency of the introduction of the alkylation group into the polysaccharide is given as a percentage in parentheses behind the DS and MS values. The viscosities of a solution at 1% of the products were measured at room temperature and at 30 rpm with a Brookfield LVT viscometer.

COMPARATIVE EXAMPLE A Approximately 50% of a solution of sodium hydroxide (80.8 g, 2.02 mol) in water (120 ml) was added to a stirred mixture of cellulose fluff (150 g), 40 ml of water and Naphol®1214-2EO glycidyl ether (120 g, 0.3 moles) under a nitrogen atmosphere at 20 ° C. After 1 hour, the mixture was heated at 85 ° C for 25 hours. The mixture was cooled, and 450 ml of ethanol, the remaining 50% of the sodium hydroxide solution and a solution of chloroacetic acid (76.5 g, 0.8 mole) in 20 ml of ethanol were added. The mixture was heated at 80 ° C for 90 minutes, cooled and neutralized with acetic acid (24 g, 0.4 moles). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder was obtained with the following analysis: DSCM 0.75 (83%), MSFAE 0.02 (6%), and a viscosity of 360 mPa.s (regular solubility in water).

EXAMPLE 1 About 30% of a solution of sodium hydroxide (80.8 g, 2.02 mol) in water (120 ml) was added to a stirred mixture of cellulose fluff (150 g), 40 ml of water, n-butyl glycidyl ether (60 g). g, 0.4 moles) and Naphol®1214-2EO glycidyl ether (90 g, 0.22 moles) under a nitrogen atmosphere at 20 ° C. After 1 hour, the mixture was heated at 85 ° C for 25 hours. The mixture was cooled, and 450 ml of ethanol, the remaining 70% of the sodium hydroxide solution and a solution of chloroacetic acid (76.5 g, 0.8 mole) in 20 ml of water were added. The mixture was heated at 80 ° C for 90 minutes, cooled and neutralized with acetic acid (24 g, 0.4 moles). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder was obtained with the following analysis: DSCM 0.75 (83%), MSBGE 0.23 (51%) and MSFAE 0.09 (36%). The product swells, but it is insoluble in water.

COMPARATIVE EXAMPLE B A solution of sodium hydroxide (80.8 g, 2.02 mol) in 120 ml of water was added to a stirred mixture of cellulose fluff (150 g) and 40 ml of water under a nitrogen atmosphere at 20 ° C. After 17 hours, a solution of chloroacetic acid (75.6 g, 0.8 mole) in water (20 ml) and Naphol®1214-2EO glycidyl ether (120 g, 0.3 mole) was added. The mixture was heated at 85 ° C for 26 hours. The mixture was cooled and neutralized with 24 g (0.4 mole) of acetic acid. The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder was obtained with the following analysis: DSCM 0.64 (71%), MSFAE 0 (0%), and a viscosity of 5800 mPa.s.

EXAMPLE 2 A solution of sodium hydroxide (80.8 g, 2.02 mol) in 120 ml of water was added to a stirred mixture of cellulose fluff (150 g) and 40 ml of water under a nitrogen atmosphere at 20 ° C. After 17 hours, a solution of chloroacetic acid (75.6 g, 0.8 mole) in water (20 ml), n-butyl glycidyl ether (60 g, 0.4 mole) and Naphol® 1214-2 EO glycidyl ether (90 g, 0.22 moles). The mixture was heated at 85 ° C for 26 hours. The mixture was cooled and neutralized with 24 g (0.4 mole) of acetic acid. The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder was obtained with the following analysis: DSCM 0.65 (72%), MSBGE 0.21 (47%), MSFAE 0.07 (28%), and a viscosity of 780 mPa.s.

EXAMPLE 3 A solution of sodium hydroxide (40 g, 1.0 mol) in 60 ml of water was added to a stirred mixture of cellulose fluff (150 g), 40 ml of water and n-butyl glycidyl ether (60 g, 0.4 moles). ) under a nitrogen atmosphere at 20 ° C. After 30 minutes, the mixture was heated at 100 ° C for 5 hours. The mixture was cooled and neutralized with acetic acid (60 g, * 1.0 moles). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder, ie, BGEC, was obtained with the following analysis: MSBGE 0.23 (51%). A solution of sodium hydroxide (40 g, 1.0 mol) in 60 ml of water was added to a stirred mixture of BGEC (154 g, 0.8 mol), 40 ml of water and Naphol®1214-2EO glycidyl ether (80 g). , 0.2 moles) under a nitrogen atmosphere at 20 ° C. After 30 minutes, the mixture was heated at 100 ° C for 5 hours. The mixture was cooled and neutralized with acetic acid (60 g, 1.0 mol). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder, ie BGE / FAEC, was obtained with the following analysis: MSBGE 0.23 (51%) and MSFAE 0.14 (56%). This product was subsequently carboxymethylated using a three-necked round bottom flask instead of a Drais mixer. A solution of sodium hydroxide (17.2 g) was added, 0.43 mol) in 26 ml of water, to a stirred mixture of BGE / FAEC (26.4 g, 0.11 mol) in 1 liter of isopropyl alcohol and 50 ml of water under a nitrogen atmosphere at 20 ° C. After 90 minutes, a solution of chloroacetic acid (15.6 g, 0.165 mol) in 20 ml of isopropyl alcohol was added. The mixture was heated at 65 ° C for 1 hour and at 80 ° C for 2 hours, cooled and neutralized with acetic acid (6 g, 1.0 mol). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C for 24 hours. A white powder was obtained with the following analysis: DSCM 0.99 (66%), MSBGE 0.23 (51%) and MSFAE 0.14 (56%). The product swells, but it is insoluble in water.

EXAMPLE 4 A solution of sodium hydroxide (28 g, 0.7 moles) in 28 ml of water was added to a stirred mixture of carboxymethyl cellulose (179 ml) with a degree of carboxymethyl substitution of 0.19, n-butyl glycidyl ether (41.9 g). , 0.3 mol), tetradecyl-penta-oxyethyl glycidyl ether (61.3 g, 0.1 mol) and 103 ml of water under a nitrogen atmosphere at 20 ° C. After 1 hour, the mixture was heated at 100 ° C for 5 hours. The mixture was then cooled and absorbed in 2 liters of 65% aqueous ethanol, and neutralized with acetic acid. The crude product was filtered and washed with 65% ethanol, 80% ethanol, 80% acetone and acetone, and dried under reduced pressure at 90 ° C for 24 hours. An off-white powder was obtained with the following analysis: DSCM 0.19, MSBGE 0.19 (63%) and MSFAE 0.039 (39%).

COMPARATIVE EXAMPLE C A solution of sodium hydroxide (52 g, 1.3 mol) in 52 ml of water was added to a stirred mixture of cellulose (168 g), tetradecyl-penta-oxyethyl glycidyl ether (122.6 g, 0.2 mol) and 75 ml of water under a nitrogen atmosphere at 20 ° C. After 45 minutes, the mixture was heated at 100 ° C for 4 hours. The mixture was cooled and absorbed in 2 liters of 65% aqueous ethanol, and neutralized with acetic acid. The crude product was filtered and washed with 65% ethanol, water, 80% ethanol, ethanol and acetone, and dried in a fluid bed dryer. An off-white powder was obtained with the following analysis: MSFAE 0.01 (5%).

EXAMPLE 5 A solution of sodium hydroxide (52 g, 1.3 mol) in 52 ml of water was added to a stirred mixture of cellulose (168 g), 2-butoxyethyl glycidyl ether (BEGE) (58.6 g, 0.3 mol), tetradecyl ether -penta-oxyethyl glycidyl (61.3 g, 0.1 mole) and 75 ml of water under a nitrogen atmosphere at 20 ° C. After 90 minutes, the mixture was heated at 100 ° C for 4 hours. The mixture was cooled and absorbed in 2 liters of 65% aqueous ethanol, and neutralized with acetic acid. The crude product was filtered and washed with 65% ethanol, water, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C. An off-white powder was obtained with the following analysis: MSBEGE 0.14 (47%) and MSFAE = -025 (25%). This product was subsequently carboxymethylated using the procedure described in Example 3.

EXAMPLE 6 Preparation of benzyl carboxymethyl cellulose A solution of sodium hydroxide (148 g, 3.7 moles) in 148 ml of water was added to a stirred mixture of cellulose fluff (205 g) and benzyl chloride (467 g, 3.7 moles) under a Nitrogen atmosphere at 20 ° C.

After 4 hours, a solution of chloroacetic acid (116.6 g, 1. 23 moles) in 30 ml of water. The mixture was heated at 90 ° C for 5 hours.

The mixture was cooled and absorbed in 2.5 I of 65% aqueous ethanol, and neutralized with acetic acid. The crude product was filtered and washed with 65% ethanol, 80% ethanol, ethanol and acetone, and dried in a fluid bed dryer of 70 ° C. A white powder was obtained.

Preparation of hydrophobically modified benzyl carboxymethyl cellulose A solution of sodium hydroxide (32 g, 0.8 mole) in 48 ml of water was added to a stirred mixture of benzyl carboxymethyl cellulose (220 g) and a mixture of dodecyl ether and tetradecyl-bis oxyethyl glycidyl (6.16 g, 0.15 moles) under a nitrogen atmosphere at 20 ° C. After 60 minutes, the mixture was heated at 100 ° C for 4 hours. The mixture was cooled and neutralized with acetic acid. The crude product was taken up in 2 liter of 65% aqueous ethanol, filtered and washed with 65% ethanol, 80% ethanol and acetone, and dried under reduced pressure at 70 ° C. A white powder was obtained.

EXAMPLE 7 Approximately 38% of a sodium hydroxide solution (104 g, 2.6 moles) in 156 ml of water was added to a stirred mixture of cellulose (150 g), n-butyl glycidyl ether (30 g, 0.22 moles), a mixture of dodecyl ether and glycidyl tetradecyl (40 g, 0.15 mol) and 50 ml of water under a nitrogen atmosphere at 20 ° C. After 60 minutes, the mixture was heated at 100 ° C for 4 hours. The mixture was cooled and 250 ml of ethanol were added, the remaining 62% of the sodium hydroxide solution and a solution of chloroacetic acid (104 g, 1.1 mol) in 25 ml of water. The mixture was heated at 80 ° C for 2 hours, cooled and neutralized with acetic acid (24 g, 0.4 moles). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C. A white powder was obtained with the following analysis: DSCM 0.84 (69%), MSBGE 0.09 (37%) and MSFAE 0.019 (11%).

EXAMPLE 8 Approximately 33% of a sodium hydroxide solution (104 g, 2.6 moles) in 156 ml of water was added to a stirred mixture of cellulose (150 g), n-butyl glycidyl ether (30 g, 0.22 mole) and 50 ml of water under a nitrogen atmosphere at 20 ° C. After 60 minutes, the mixture was heated at 100 ° C for 1 hour. A mixture of hexadecyl- and octadecyl-bis-oxy-glycidyl ether (30 g, 0.06 mol) was added to the hot reaction mixture, and heated at 100 ° C for a further 4 hours. The mixture was cooled and 250 ml of ethanol, the remaining 67% of the sodium hydroxide solution and a solution of chloroacetic acid (104 g, 1.1 mol) in 25 ml of water were added. The mixture was heated at 80 ° C for 2 hours, cooled and neutralized with acetic acid (24 g, 0.4 moles). The crude product was washed three times each time with 65% ethanol, 80% ethanol, ethanol and acetone, and dried under reduced pressure at 70 ° C. A white powder was obtained with the following analysis: DSCM 0.87 (71%), MSBGE 0.043 (27%) and MSFAE 0.012 (18%), and a viscosity of 416 mPa.s.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - An ether anionic cellulose hydrophobically modified obtainable by a process comprising reacting cellulose alkali metal not possessing a hydroxyalkyl group, with at least three alkylating reagents A, B and C, one or more reagents A being selected from the group of halogenoacetic acids, alkali metal halogenoacetates, alkali metal vinyl sulfonates and vinyl sulfonic acid, one or more reagents B having the formula R1- (OCH2CH (R2)) nP. wherein R1 represents a group of C2-C, R2 is hydrogen or a methyl group, n is from 0 to 2, and P represents a glycidyl ether group, a 3-halogeno-2-hydroxypropyl ether group, a group 1 , 2-epoxy, or a haiogenide, and one or more reagents C having the formula R3- (OCH2CH (R2)) mP, wherein R3 represents a group of C8-C3o, m is from 0 to 10, and R2 and P have the meaning described above.

2. The cellulose ether according to claim 1, further characterized in that the reagent A consists essentially of chloroacetic acid.

3. The cellulose ether according to claim 1 or 2, further characterized in that P is a glycidyl ether group.

4. - The cellulose ether according to any of the preceding claims, further characterized in that the reagent B is butyl glycidyl ether.

5. The cellulose ether according to any of the preceding claims, further characterized in that R3 is a group of C.2-C22.

6. The cellulose ether according to any of the preceding claims, further characterized in that reagent C is sodium dodecyl glycidyl ether, tetradecyl glycidyl ether, hexadecyl glycidyl ether, octadecyl glycidyl ether, dodecyl-bis-oxyethyl glycidyl ether, tetradecyl ether bis-oxyethyl glycidyl ether, hexadecyl-bis-oxyethyl glycidyl ether, octadecyl-bis-oxyethyl glycidyl ether, tetradecyl-penta-oxyethyl glycidyl, or a mixture thereof.

7. The cellulose ether according to any of the preceding claims, further characterized in that the alkali metal cellulose is reacted with reagents A, B and C while the temperature is gradually increased.

8. The cellulose ether according to any of claims 1 to 6 above, further characterized in that the alkali metal cellulose is reacted first with reagents B and C, and then with reagent A. 9.- The ether of cellulose according to any one of claims 1 to 6 above, further characterized in that the alkali metal cellulose is reacted first with reagent A, and then with reagents B and C. 10. The cellulose ether in accordance with any of the preceding claims, further characterized in that the process is carried out using a minimum amount of a diluent. 11. The cellulose ether according to any of the preceding claims, further characterized in that the alkali metal cellulose is reacted with four alkylating reagents, A, B, C and D, wherein A, B and C have the The meaning described in any of the preceding claims, and D is a quaternary ammonium compound. 12. The use of a hydrophobically modified anionic cellulose ether according to any of the preceding claims as a protective colloid, stabilizer, emulsifier, thickener or rheology modifier.