PL206376B1 - Method for obtaining polyol component intended for the synthesis of flexible polyurethane porous materials - Google Patents

Description

(12) PATENT DESCRIPTION (19) PL (11) 206376 (13) B1 (21) Application number: 372612 (51) Int.Cl.

C08G 18/36 (2006.01) C07C 41/03 (2006.01) (22) Date of notification: 04/02/2005

A method of obtaining a polyol component intended for the synthesis of flexible, polyurethane porous materials

(73) The right holder of the patent: CRACOW UNIVERSITY OF TECHNOLOGY THEM. TADEUSZA KOŚCIUSZKI, Cracow, PL (43) Application was announced: 07.08.2006 BUP 16/06 (72) Inventor (s): JAN PIELICHOWSKI, Krakow, PL ALEKSANDER PROCIAK, Krakow, PL PIOTR CZUB, Krakow, PL (45) The grant of the patent was announced: August 31, 2010 WUP 08/10 (74) Representative: item. stalemate. Andrzej Stachowski

PL 206 376 B1

Description of the invention

The subject of the invention is a method of obtaining a polyol component intended for the synthesis of flexible, polyurethane porous materials with the use of vegetable oil.

Polyhydric alcohols used in the production of polyurethanes are petrochemical products. These compounds are not renewable raw materials, and their production is energy-consuming and poses a threat to the natural environment. Moreover, the price of polyols is unpredictable due to the fluctuating value of crude oil. Therefore, attempts are being made to replace polyester and polyetherols used in the production of polyurethanes with materials of natural origin, more versatile, regenerable, cheaper to produce and more environmentally friendly. Polyols can be replaced with such vegetable oils as: soybean, linseed, rapeseed, cotton, peanut and palm oil. Epoxidized higher fatty acids of plant origin are also introduced into the production of polyurethane plastics. Natural oils are cheap, versatile in use, ecological and desirable as ingredients for the production or modification of plastics.

Vegetable oils, before being used as a polyol component for the production of polyurethane foams, are subjected to two unit processes. In the first stage, unsaturated bonds of higher fatty acids are epoxidized (most often with peracids, generated in the reaction medium), and then the oxidized oils are reacted with alcohol in order to open epoxy rings.

The solutions known from the English patents No. 739 609, 769 127 and 790 063 describe the epoxidation processes of natural oils, which are most often carried out in the system: hydrogen peroxide and aliphatic carboxylic acid, in the presence of an acid catalyst. The actual oxidizing agent is the organic peracid which is formed in situ by the reaction of the acid with hydrogen peroxide and reacts with the unsaturated bonds present in the oil. The most commonly used are carboxylic acids containing from 1 to 7 carbon atoms. However, reactions carried out with formic acid have to be carried out over a longer period of time than is the case with other carboxylic acids. Moreover, it is difficult to recover formic acid due to its close to water boiling point, hence the cost of using formic acid is quite high; here, the performic acid is considered to be very unstable. On the other hand, when acetic acid is used, products with a lower iodine number are obtained than in the case of the reaction with formic acid, however, acetic acid remains the most frequently used component of the oxidation mixture. In the known solutions, the amounts are introduced in the amount of 0.05-0.7 moles for each double bond in one mole of the ester. In another embodiment, however, the amount of acetic acid is preferably 0.25-1.00 moles for each mole of unsaturation. The lower the amount of acid used, the slower the reaction rate, and the slower the reaction rate, and in the case of an excess amount of acid, the epoxidized product is contaminated with the hydroxyacetone by-product. Acetic anhydride in an amount of 0.6 to 2 moles for each double bond in each mole of ester can also be used in the solution known from English Patent Specification No. 790,063. In the known solutions disclosed in British Patent Nos. 739,609, 769,127, 790,063, 811,852 and 1,020,779, the most commonly used oxidizing agent is hydrogen peroxide. It is used in an amount of at least 1.0 mole for each ester double bond, with the concentration of the aqueous solution depending on the amount of the acid component used. As a rule, these are 35-90% solutions, although it is preferable to use solutions containing at least 50% by weight of hydrogen peroxide. Higher concentrations of hydrogen peroxide solutions are used at lower temperatures and with lower amounts of acetic acid, while more dilute solutions are used at higher temperatures in combination with larger amounts of acid agent. Typically a slight excess of H 2 O 2, on the order of 0.1 mol, is used, but can be as high as 1.0 mol.

The most commonly used catalysts for the oxidation process are: inorganic acids (phosphoric (V), sulfuric (VI), hydrochloric, boric) or their salts (sodium bisulfate, potassium bisulfate, zinc chloride); organic sulfonic acids (e.g. p-toluenesulfonic acid) or other organic acids (maleic, fumaric, oxalic); acid esters (ethyl diphosphate, isopropyl diphosphate, monohydroxymethyl sulfate). The acid catalyst should have low solubility in the organic ester phase and be insoluble in the epoxidized ester. Hence, inorganic acids are most often used. The acid catalyst should also not decompose more than 35% of the epoxy groups formed. The most common types of acid are phosphoric (V) and sulfuric (VI) acid, in amounts ranging from 0.5 to 5% based on the total weight of acetic acid and hydrogen peroxide. According to the solutions presented in the English patents No. 739 609, 769 127 and 811 852 at

When no or too little catalyst is present, the yield of oxidation to epoxy groups is significantly reduced. The advantage of carrying out the process in the presence of sulfuric acid is a high degree of converted double bonds and a small amount of by-products.

Epoxidation reactions are also catalyzed by basic or permanently neutral salts of metals from groups IA and IIA of the periodic table (sodium, potassium, lithium, calcium and barium acetate; sodium and potassium phosphates, sodium and potassium bromides and fluorides; sodium and potassium borates and fluoroborates; formates , oxalates, tartrates, citrates and chloroacetates). The hydroxides, oxides, carbonates and bicarbonates of metals of Groups I and II of the Periodic Table may also be used, since they react with the acetic acid present in the reaction mixture and form the corresponding acetates. Salt oxidizing in the reaction medium and heavy metal salts which catalyze the decomposition of hydrogen peroxide should not be used. According to the solutions presented in the English patents No. 739 609 and 769 127, the catalyst together with acetic acid should provide a pH in the range between +1.0 and -1.0 at the beginning of the reaction (as presented in the solutions known from the English patents No. 769 127 and 811). 852 if the pH exceeds +1.5, the epoxidation rate slows down).

The oxidation reaction can be carried out without the use of a solvent (the organic phase consists of vegetable oil itself) or in a solvent.

The solvents used should not be miscible with water and are usually hydrocarbons such as toluene, xylene, heptane and octane as well as ethylene dichloride and carbon tetrachloride. The reaction temperature should be kept in the range of 10 to 100 ° C, with the most commonly used temperatures being in the range of 60 to 80 ° C.

By opening the oxirane rings of epoxidized fatty acids or their esters by reaction with a hydrogen donor, products with long polyol chains are obtained. The epoxy group located centrally in the fatty acid chain is not very active and the opening of its ring requires carrying out the reaction at high temperature, in the presence of strong catalysts, and often even under increased pressure. The following are used as nucleophilic factors in epoxy ring opening reactions: water, aliphatic alcohols, glycols and aliphatic amines. Depending on the type of fatty material and the nucleophilic factor, the reactions are carried out at the temperature of 50-250 ° C for 1-6 hours. The oil derivatives obtained in this way are the raw material from which it is possible to obtain hydroxy fatty acids with two adjacent hydroxyl groups by transesterification and hydrolysis. As a rule, a ring-opening efficiency of 94-100% is obtained, and the polyol product has a hydroxyl number in the range of 10-400. As shown in the disclosure of U.S. Patents Nos. 4,826,944 and 6,057,375, the products can be highly viscous liquids, which may in individual cases be described as low viscosity solids or liquids. For example, described in the "Chemical Industry", 2001, vol. 80, page 154, the hydroxyl derivative of rapeseed oil has the form of a thick, semi-solid, smooth mass, has a very high viscosity, brown color, and the hydroxymethoxy derivative is a thick, oily liquid with a large viscosity and orange color. As shown in US Patent Nos. 6,057,375 and 6,281,392 products with a high content of epoxy groups can form dispersions and emulsions in water without additional external emulsifiers (self-emulsifying compounds in water).

Mineral acids and Lewis acids are used as catalysts for the epoxy ring opening reaction, in an amount of 1-4 g per mole of epoxy groups. For example, phosphoric (V) acid, phosphoric (III) acid and phosphoric (I) acid, sulfuric (VI) acid, p-toluenesulfonic acid, succinosulfonic acid (according to US Patent No. 5,380,886), strong acid bleaching earth are used or active earth additionally activated with a solution of sulfuric acid (VI) to an acidity corresponding to a concentration of 4.9-6.2% H2SO4 (described in "Przemysł Chemiczny", 2001, vol. 80, page 154). All catalysts, except phosphoric acid, are removed after the reaction in order to accurately determine the epoxy number. Acids can be removed from the reaction medium by standard methods, e.g. by absorption on solid materials or by neutralization with bases, e.g. NaOH, KOH, LiOH (according to the solution presented in US Patent No. 5,688,989, lithium salts can also be used), Na2CO3 or amines, e.g. diethylethanolamine, dimethylethanolamine, ethanolamine, morpholine or ammonia. Sodium methoxide can also be used for neutralization in the solution disclosed in US Patent No. 4,826,944. The neutralized acid catalyst residues remain in the resulting product. The catalyst can be introduced into the reaction mixture entirely or dissolved in alcohol and dosed in small portions, bearing in mind that the introduction of the catalyst increases the temperature of the reaction mixture.

PL 206 376 B1

Nucleophilic factors most often used to open the rings of epoxidized vegetable oils are water and monohydric alcohols containing from 1 to 22 carbon atoms in the alkyl chain (in the solution known from US Patent No. 5,380,886) but also up to 54 carbon atoms (as shown in in another embodiment known from US Patent No. 6,057,375). They can also contain from 1 to 3 double bonds, a straight or branched chain hydrocarbon and are usually: methanol, ethanol, 1-propanol, 2-propanol, n-butanol n-pentanol, n-hexanol and 2-ethylhexanol used in a stoichiometric amount in relation to the epoxy group content in the oil, or with a molar excess from 1.05 to 10 times (according to US Patent No. 4,826,944). The most commonly used monohydric alcohols are methanol and ethanol. The second group consists of fatty alcohols containing from 6 to 22 carbon atoms (according to US Patent No. 6,057,375, preferably when they contain from 8 to 18 carbon atoms): cyclohexanol, benzyl alcohol, octanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol , oleic, erucic or diol dimers / trimers obtained by hydrogenation of fatty acid esters. A very important group of compounds are polyhydroxy alcohols with a preferred content of hydroxyl groups from 2 to 8, e.g. ethylene glycol, diethylene glycol, polyethylene glycols with molecular weights in the range 300-1500 g / mol, propane-1,2-diol, propan-1, 3-diol, butane-1,4-diol, hexane-1,6-diol, neopentyl glycol, glycerol, oligoglycerols with a condensation degree of 2-10 on average, trihydroxymethylpropane, pentaerythritol, sorbitol, sorbitan. Ethylene glycol, 1,2-propane diol, glycerol, and trihydroxymethylpropane are preferred. It is known from the solution disclosed in US Patent No. 4,825,004 that the following were also used: a fatty alcohol polyglycerol ether, a fatty alcohol ether containing a linear or branched hydrocarbon chain consisting of 6-22 carbon atoms and from 1 to 3 double bonds; carboxylic acids contain from 1 to 8 carbon atoms (preferably 1-3), e.g. formic acid, acetic acid, propionic acid; fatty acids containing 6-22 carbon atoms, fatty acid dimers and trimers; ricinoleic acid, hydroxystearic acid, benzoic acid or a mixture of these acids. It is most preferred to use mixtures of fatty acids with a chain length of 6 to 12 carbon atoms. The chemical structure of the alkyl radical of carboxylic acids and the alcohol components of the epoxidized fatty acid esters should be the same. The solution known from US Patent No. 4,825,004 also produces alcohol esters which give the corresponding triols in the hydroxylation reaction. On the other hand, in another embodiment described in US Patent No. 3,931,075, acrylic and methacrylic acid are also used to open epoxy rings.

In order to ensure the opening of all epoxy rings present in the modified oil, an excess of nucleophilic factor in relation to the content of epoxy groups is most often used. The molar ratio presented in the solution known from US Patent No. 6,057,375 is as a rule: 1: 2 or 1: 3, but extreme ratios are also used, starting with a slight excess of nucleophilic factor, in the order of 1.05 (according to the US description Patent No. 4,826,944), up to 10: 1 (in accordance with US Patent No. 5,380,886). After the reaction, excess nucleophile is distilled off under reduced pressure. However, in the case of the reaction of epoxidized fatty acid esters with dicarboxylic acids or glycols, an equal ratio of the two components is maintained.

As catalysts for the epoxy ring opening reaction, mineral acids or Lewis acids are used in an amount of 1-4 g per mole of epoxy groups. If sulfuric (VI), p-toluenesulfonic or acetic acid is used, neutralize them after the reaction is completed so as not to distort the epoxy number determination. The most commonly used neutralization methods are: ethanolamine, morpholine, diethylethanolamine, diethanolamine or dimethylethanolamine.

The aim of the invention is to develop a method for the preparation of a polyol component that can be used for the synthesis of flexible, polyurethane porous materials with the use of natural vegetable oil.

The method of obtaining a polyol component intended for the synthesis of flexible, polyurethane porous materials in a two-stage process consisting in epoxidation of vegetable oil using an oxidizing system consisting of acetic acid and hydrogen peroxide solution in the first stage and reacting the oxidized oil with ethylene glycol in the second stage, according to the invention on the fact that rapeseed oil is subjected to the epoxidation reaction in an oxidation system containing 30% hydrogen peroxide solution, with the molar ratio of acetic acid to the content of unsaturated bonds in the oil being 0.3 to 1.0 and the molar ratio of peroxide

Hydrogen to an unsaturated content of the oil of 1.0 to 1.4. The epoxidation reaction is carried out in a solvent, preferably toluene, in the presence of a sulfuric acid catalyst, introduced in an amount of 3 to 12 parts by weight per 100 parts by weight of the total weight of acetic acid and hydrogen peroxide used in the reaction, with a reaction temperature of from 50 to 70 ° C for 4 to 12 hours. In the second step of the process, the oxidized oil is reacted with ethylene glycol in a stoichiometric amount with respect to the epoxy group content in the oil, in the presence of an acid catalyst, the acid catalyst being used in an amount of 0.8 to 2 g, preferably 1 g of acid per oil. 1 mole of epoxy groups in the oil, and the reaction is carried out at a temperature of 100 to 120 ° C for 3 to 24 g of hours. Preferably, the acid catalyst in the second process step is 85% phosphoric acid or 95% sulfuric acid.

After the first stage of the process, products with an iodine number from 1 to 61 and an epoxy number from 0.131 to 0.379 are obtained. The product is washed with hot water to remove acetic acid and then toluene and water are removed by vacuum distillation. After completion of the second stage and neutralization of the acid catalyst with diethylethanolamine, light or dark products are obtained, with a viscous liquid or solid consistency and with a hydroxyl number from 60 to 84, depending on the type of acid catalyst used, the reaction time and the degree of conversion. The obtained oil modified by the method according to the invention can be used in the process of polyurethane foam synthesis by replacing from 5 to 100% of the polyol component.

Depending on the hydroxyl number of the rapeseed oil-based polyol used in the synthesis, microporous materials or flexible foams are obtained.

The method according to the invention allows for partial or complete replacement of petrochemical polyols with easily obtainable, cheap and ecological products of natural origin, with modified rapeseed oils.

P r z x l a d I.

100 g of soybean oil (iodine number 129), 100 g of toluene, 12.5 g of glacial acetic acid and 1.96 g of 95% sulfuric acid ( VI). The mixture is heated to 55-60 ° C and then 84.1 g of 30% H 2 O 2 are introduced over an hour. After all of the H 2 O 2 had been given up, the reaction was carried out for 6 h at a temperature between 60-65 ° C. The lower aqueous layer is then separated and the oil layer is washed with hot water until the acetic acid is washed out. The acid-washed oil is subjected to vacuum distillation at 60-70 ° C to remove residual solvent and water.

The reaction product is a light yellow oil with an iodine number of 27.79 and an epoxy number LEP = 0.236, i.e. with an oxidized unsaturation content of 78.5%.

Example 11-IV according to the invention

Proceeding as in Example 1, using rapeseed oil and the amounts of sulfuric acid, glacial acetic acid and 30% hydrogen peroxide used. In the aqueous solution given in Table I, epoxidized rapeseed oils are obtained as described in Example 1, which are then subjected to an epoxy ring opening reaction with ethylene glycol. Table I shows the epoxidation reaction parameters and product properties.

P r z k ł a d V

100 g of epoxidized soybean oil (LEP = 0.236), 14.63 g of ethylene glycol and 0.239 g of 85% phosphoric acid (V) are introduced into a 250 ml three-neck flask equipped with a thermometer, a reflux condenser and a stirrer. The reaction is carried out at 110 ° C for 4 hours (until all epoxy rings present in the oil are opened). After completion of the reaction, the sulfuric acid is neutralized with diethylethanolamine.

The reaction product is a yellow oil with an iodine number of 27.79 and a hydroxyl number of LOH = 95.

Example VI-VIII according to the invention

Proceeding as in Example 5 and using epoxidized rapeseed oil (Examples VI-VIII) and the type and amount of acid catalyst used, as well as the amount of ethylene glycol given in Table II, the modified vegetable oils are obtained as in Example 5 and which are then is used for the synthesis of flexible, polyurethane porous materials. Table II shows the performance of the oil-based polyols after the epoxy ring opening reaction.

PL 206 376 B1

T a b e l a I

Quantity used H2SO4 [moth] Number of used of this glacial CH3COOH [mol] Amount of H2O2 used [mol] number iodine before epoxy dinner Content bindings unassuming- what before epoxy dinner [moth] number iodine after epochs sidation Content bindings unassuming- post epoxidation [mol] Content of unsaturated bonds after epoxidation [%] LEP AND 0.032 0.233 0.568 129.0 0.507 58.11 0.228 45.05 0.206 II 0.007 0.080 0.193 112.0 0.441 61.40 0.241 54.74 0.131 III 0.047 0.441 0.575 112.0 0.441 46.30 0.182 41.28 0.227

T a b e l a II

number iodine LEP before reaction Type of catalyst used The amount of catalyst used [g] Amount of ethylene glycol used [mol] LEP after reaction LOH VI 58.11 0.216 85% Phosphoric (V) acid 0.216 0.216 0 77 VII 46.30 0.225 85% Phosphoric (V) acid 0.225 0.225 0 84 VIII 61.40 0.131 95% Sulfuric (VI) acid 0.131 0.131 0 60

Patent claims

Claims (2)

1. The method of obtaining a polyol component intended for the synthesis of flexible, polyurethane porous materials in a two-stage process consisting in epoxidation of vegetable oil using an oxidizing system consisting of acetic acid and hydrogen peroxide solution in the first stage and reacting the oxidized oil with ethylene glycol in the second stage, characterized by the epoxidation reaction is applied to rapeseed oil in an oxidation system containing 30% hydrogen peroxide solution, with the molar ratio of acetic acid to the content of unsaturated bonds in the oil being 0.3 to 1.0 and the molar ratio of hydrogen peroxide to the content of unsaturated bonds in the oil from 1.0 to 1.4, and the reaction is carried out in a solvent, preferably toluene, in the presence of a sulfuric acid catalyst fed in an amount of 3 to 12 parts by weight per 100 parts by weight of the total weight used in the reaction acetic acid and hydrogen peroxide at a temperature of from an epoxidation reaction ranging from 50 to 70 ° C for a period of 4 to 12 hours, while in the second stage, the oxidized oil is reacted with ethylene glycol used in a stoichiometric amount in relation to the content of epoxy groups in the oil, in the presence of an acid catalyst in the amount of 0.8 to 2 g, preferably 1 g of acid per mole of epoxy groups in the oil, the reaction being carried out at a temperature of 100 to 120 ° C for a period of 3 to 24 hours. 2. The method according to p. A process as claimed in claim 1, characterized in that the acid catalyst in the second process step is 85% phosphoric acid or 95% sulfuric acid. Publishing Department of the Polish Patent Office