CN101735254B - A kind of synthetic method of borate - Google Patents

Abstract

The invention provides a synthesis method of borate, which takes acidic ionic liquid as a solvent and a catalyst to catalyze the esterification reaction of inorganic boric acid and alcohol to obtain borate, wherein the alcohol can be monohydric, dihydric aliphatic alcohol or monohydric cycloalkyl alcohol, the prepared borate can be trialkyl borate or mixed alkyl and cycloalkyl borate, the acidic ionic liquid adopts imidazole ionic liquid, pyridine ionic liquid or quaternary ammonium salt ionic liquid, and the following molecular structural formula substances are selectedCompared with the traditional preparation method, the method adopts the acidic ionic liquid to replace a large amount of benzene organic solvents used in the traditional method, reduces the environmental pollution, has mild reaction conditions, simple and convenient operation, easy separation of products, reusability of the ionic liquid and large-scale application prospect.

Description

A kind of synthetic method of borate

technical field

The present invention relates to the preparation method of borate. Specifically, the boric acid ester is prepared by using a water-stable and water-soluble acidic ionic liquid as a reaction medium and a catalyst.

Background technique

Boric acid ester is a kind of inorganic acid ester compound, itself and its derivatives can be applied in many fields. For example, it can be used as an efficient and environmentally friendly lubricant, antirust agent, modified nanomaterial rubber filler, surfactant, bonding agent in solid propellant, composite graphite sealing material, epoxy resin curing accelerator, automobile brake fluid, Metal-rubber adhesion promoters, antistatic agents, flame retardants, emulsifiers, photoinitiators and thermal initiators, preservatives and anti-neutron radiation materials, etc.

There are five main methods for traditionally preparing boric acid esters: (1) the reaction of boron trichloride and alcohol or phenol, (2) the reaction of boric acid and alcohol or phenol, (3) the reaction of boric anhydride and alcohol or phenol, (4) The reaction of borax with alcohol or phenol under acid catalysis, (5) transesterification reaction. The first method uses lively and expensive boron trichloride, which is not suitable for mass production. The second method uses a large amount of aromatic hydrocarbons as solvent and water-carrying agent, which will cause greater harm to the environment. The third method can produce more by-products, and the yield is not high. The fourth method uses strong acids such as corrosive sulfuric acid, which requires high equipment use and maintenance costs and pollutes the environment. The fifth method has a two-step reaction. Firstly, a simple and easy-to-obtain borate is prepared, and then exchanged with alcohol or phenol to obtain the corresponding borate. Therefore, the production efficiency of this method is not high.

Since the ionic liquid was synthesized, people have been exploring its application in chemistry and chemical industry. In recent years, ionic liquids have shown a multifunctional development trend, and various functional ions have been synthesized, such as chiral ionic liquids. Acidic ionic liquids, basic ionic liquids, supported ionic liquid catalysts and reagents, and ionic liquids for target molecular carriers, etc. The application of ionic liquids in the chemical field is also becoming more and more extensive, such as oxidation of olefins and alcohols, Baeyer-Villiger reaction, esterification reaction, reduction and reverse catalytic hydrogenation reaction (, Friedel-Crafts reaction, Diels-Alder reaction, carbon-carbon Coupling reaction (Heck, Suzuki), addition reaction (Knovenagel, Michael), hydroformylation reaction, substitution reaction, etc. In addition, the development of ionic liquid research is not limited to the application in synthetic chemistry and catalytic reaction, has been Expanded to many fields such as process engineering, functional materials, environmental engineering and life sciences. Utilizing the selective dissolution characteristics of ionic liquids, BASF successfully developed a process for the preparation of alkylphenylsulfone in 2002, which is considered by the industry to be an ionic The earliest example of large-scale application of liquid.

Contents of the invention

All the technical problems solved by the present invention are aimed at the problems existing in the traditional esterification method for preparing inorganic boric acid and alcohol, and develop a new synthetic method of boric acid ester with water-soluble acidic ionic liquid as reaction medium and catalyst. Compared with the traditional method, the method has the advantages of simple operation, short reaction time, easy separation, avoids the use of aromatic hydrocarbons as solvents, has little environmental pollution, and is suitable for large-scale production.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a synthetic method of boric acid ester, which is characterized in that in acidic ionic liquid, the esterification reaction of boric acid and alcohol is catalyzed to obtain boric acid ester; the acidic ionic liquid used Using imidazole ionic liquid, pyridine ionic liquid or quaternary ammonium salt ionic liquid, the acidic ionic liquid is one of the following, which can be imidazole ionic liquid (I-1), pyridine ionic liquid (I-2) Or quaternary ammonium salt ionic liquid (I-3):

Wherein, the meaning of R ¹ is H, or sulfonic acid propyl group; the meaning of R ² is H, or sulfonic acid propyl group; the meaning of X is HSO ₄ , BF ₄ , o-CH ₃ C ₆ H ₅ SO ₃ , or _CH3COO .

The borates prepared are any of the following, homo-alkyl borate (II-1), homo-cycloalkyl borate (II-2), mixed cycloalkyl-1,2-oxo Hetero-alkyl borates (II-3):

Wherein R ³ is one of methyl, ethyl, propyl, isopropyl, n-butyl, or n-octyl.

The technical solution provided by the invention is a method for catalytically synthesizing boric acid ester with an acidic ionic liquid, specifically:

Mix the ionic liquid, boric acid, and alcohol in a certain molar ratio (ionic liquid: boric acid: monohydric alcohol = 0.5-10:1:3, or ionic liquid: boric acid: monohydric alcohol: dihydric alcohol = 0.5-10:1:1:1 ) was added to the reaction flask, and the reaction was stirred. The reaction temperature can be from room temperature to 90 degrees, and the reaction time is 2 to 15 hours. After the reaction was completed, the mixture was allowed to stand for stratification. The upper organic layer was taken out, and fractional distillation was carried out to obtain the product boric acid ester. For a non-layered system, a small amount of organic solvent can be added to extract the boric acid ester, and then the product can be obtained by fractional distillation. The lower ionic liquid layer is washed 2-5 times with a small amount of organic solvent, heated and decompressed to remove water and organic matter, and then reused.

The organic solvent used above can be diethyl ether, petroleum ether, benzene, or toluene and the like.

When preparing borate II-1, which is easier to absorb moisture and hydrolyze, the reaction and separation should be carried out under inert gas nitrogen or argon; when preparing borate II-2 or II-3 with better hydrolytic stability, the reaction Can operate in air.

Compared with the prior art, the present invention has the advantages of: (1) no need to use strong acids such as highly corrosive sulfuric acid, which reduces environmental pollution and equipment maintenance costs; (2) no need to use a large amount of toxic and harmful The benzene solvent used as a solvent and water-carrying agent reduces the pollution to the environment; (3) the water-stable acidic ionic liquid constantly moves the water produced in the esterification process out of the organic layer and enters the ionic liquid layer to speed up and The progress of the esterification reaction is promoted; (4) the separation of the product is easy; (5) the acidic ionic liquid can be reused after simple dehydration treatment.

Detailed ways

Below in conjunction with embodiment the present invention is described in further detail.

The embodiments of the present invention will be described below through examples, which do not limit the protection scope of the present invention. The ionic liquid used in the implementation example: protonated methylimidazolium-hydrogensulfate anion ([Hmin] ⁺ HSO ₄ ^- ), protonated methylimidazolium-tetrafluoroborate ion ([Hmim] ⁺ BF ₄ ^- , protonated Triethylamine-acetate anion ([Et ₃ NH] ⁺ [CH ₃ COO ^- ]), methylimidazolium propanesulfonate-hydrogen sulfate anion ([(CH ₂ ) ₃ SO ₃ Hmin] ⁺ HSO ₄ ^- ), Triethylaminopropanesulfonic acid-hydrogensulfate anion ([(CH ₂ ) ₃ SO ₃ HTEA] ⁺ HSO ₄ ^- ), pyridinepropanesulfonic acid-hydrogensulfate anion ([(CH ₂ ) ₃ SO ₃ HPy] ⁺ HSO ₄ ^- ), protonated triethylamine-tetrafluoroborate ion ([Et ₃ NH] ⁺ BF ₄ ^- ), pyridine propanesulfonic acid-p-toluenesulfonate anion ([(CH ₂ ) ₃ SO ₃ HPy] ⁺ [o-CH ₃ C ₆ H ₅ SO ₃ ] ^- ), pyridine propanesulfonic acid-tetrafluoroborate ion [(CH ₂ ) ₃ SO ₃ HPy] ⁺ BF ₄ ^- ), prepared according to published methods (Yue Caibo , Wei Yuanyang, Lu Minjie, Applied Chemistry 2006, 23, 1282-1285. H.-P.Zhu, F.Yang, J.Tang, M.-Y.He; Green Chem., 2003, 5, 38-39. C.-M. Wang, L.-P. Guo, H.-R. Li, Y. Wang, J.-Y. Weng, L.-H. Wu; Green Chem., 2006, 8, 603-607. ACCole, JL Jensen, I.Ntai, KLTTran, KJWeaver, DCForbes, JHDavis, Jr.; J.Am.Chem.Soc., 2002, 124, 5962-5963. J.-Z.Guo, X.-H.Cong , D.Liu, X.-T.Zhang, Z.-D.Hu, Z.-L.Sun; Catal.Commun., 2004, 5, 473-477.C.-M.Wang, L.-P .Guo, H.-R.Li, Y.Wang, J.-Y.Weng, L.-H.Wu; Green Chem., 2006, 8, 603-607. Wang Tao, Xing Huabin, Zhou Zhenhuan, Dai Youyuan, Patent No. CN1594280A).

Implementation example 1:

Put 1.8g (10mmol) ionic liquid [Hmim] ⁺ HSO ₄ ^- , 0.62g (10mmol) boric acid and 1.38g (30mmol) ethanol into the reaction flask, stir, heat, control the temperature at 80°C, react for 2h, the reaction solution Stand still, no layering, transparent solution, and extract the product triethyl borate with petroleum ether under nitrogen atmosphere. Qualitative and quantitative analysis by GC-MS gave a yield of 74%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 2:

Put 1.8g (10mmol) ionic liquid [Hmim] ⁺ HSO ₄ ^- , 0.62g (10mmol) boric acid and 1.8g (30mmol) isopropanol into the reaction flask, stir, heat, control the temperature at 80°C, and react for 2h, The reaction solution was allowed to stand, and the layers were separated, and the upper layer was a colorless clear solution. Under a nitrogen atmosphere, the esterification product triisopropyl borate was separated. The yield was 89.7% by GC-MS qualitative and quantitative analysis. The lower ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 3:

Put 1.8g (10mmol) ionic liquid [Hmim] ⁺ HSO ₄ ^- , 0.62g (10mmol) boric acid and 2.64g (30mmol) n-butanol into the reaction flask, stir, heat, control the temperature at 80°C, and react for 2h. The reaction solution was allowed to stand and separated into layers. The upper and lower layers were both colorless and clear solutions. Under a nitrogen atmosphere, the esterification product tributyl borate was separated. The yield was 98.9% through qualitative and quantitative analysis by GC-MS. The lower ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 4:

Put 1.8g (10mmol) ionic liquid [Hmim] ⁺ HSO ₄ ^- , 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, stir, heat, and control the temperature 80°C, react for 2 hours, let the reaction solution stand still, and separate layers, the upper and lower layers are light yellow transparent solutions, and the esterification product cyclohexanol pinacol borate is separated by liquid separation. The yield was 73.7% by GC-MS qualitative and quantitative analysis. The lower ionic liquid layer was washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter, and then reused 3 times. After qualitative and quantitative analysis by GC-MS, the yields were 83.9%, 64.87%, and 65.27%, respectively. %.

Implementation example 5:

Put 1.8g (10mmol) ionic liquid [Hmim] ⁺ HSO ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, at room temperature (30°C) Stir. After reacting for 2 hours, the reaction solution was allowed to stand still and layered. The upper and lower layers were light yellow transparent solutions, and the esterification product cyclohexanol pinacol borate was separated by liquid separation. The yield was 76.48% by GC-MS qualitative and quantitative analysis.

Implementation example 6:

Put 1.7g (10mmol) ionic liquid [Hmim] ⁺ BF ₄ ^- , 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, stir, heat, and control the temperature 80°C, reacted for 6 hours, the reaction solution was left standing, without stratification, it was a light yellow milky liquid, extracted with petroleum ether, and the esterification product cyclohexanol pinacol borate was obtained, which was obtained through qualitative and quantitative analysis by GC-MS The yield was 78.56%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 7:

Put 1.61g (10mmol) ionic liquid [Et ₃ NH] ⁺ [CH ₃ COO ^- ], 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, stir , heating, controlling the temperature at 80°C, and reacting for 6 hours. The reaction solution was allowed to stand still without delamination. Quantitative analysis gave a yield of 96.3%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 8:

Put 3.02g (10mmol) ionic liquid [(CH ₂ ) ₃ SO ₃ Hmin] ⁺ HSO ₄ ^- , 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask , stirring, heating, controlling the temperature at 80°C, and reacting for 6 hours. The reaction solution was allowed to stand and separated into layers. MS qualitative and quantitative analysis gave a yield of 82.1%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 9:

Put 3.21g (10mmol) ionic liquid [(CH ₂ ) ₃ SO ₃ HTEA] ⁺ HSO ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask , Stir, heat, control the temperature at 80°C, react for 6h, let the reaction solution stand, and separate layers. -MS qualitative and quantitative analysis obtained a yield of 72.71%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 10:

Put 2.99g (10mmol) ionic liquid [(CH ₂ ) ₃ SO ₃ HPy] ⁺ HSO ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask , Stir, heat, control the temperature at 80°C, react for 6h, let the reaction solution stand, and separate layers, the upper layer is a reddish-brown liquid, the lower layer is a yellow liquid, and the esterification product cyclohexanol pinacol borate is separated by liquid separation , the yield was 80.13% through GC-MS qualitative and quantitative analysis. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 11:

Put 2.99g (10mmol) ionic liquid [(CH ₂ ) ₃ SO ₃ HPy] ⁺ HSO ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask , Stir, heat, control the temperature at 80°C, react for 6h, let the reaction solution stand, and separate layers, the upper layer is a reddish-brown liquid, the lower layer is a yellow liquid, and the esterification product cyclohexanol pinacol borate is separated by liquid separation , the yield was 80.13% through GC-MS qualitative and quantitative analysis. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 12:

Put 1.88g (10mmol) ionic liquid [Et ₃ NH] ⁺ BF ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, stir, heat, Control the temperature at 80°C, react for 2 hours, let the reaction solution stand still, without stratification, light yellow solution, extract with petroleum ether, and obtain the esterification product cyclohexanol pinacol borate, which is obtained by qualitative and quantitative analysis by GC-MS The yield was 72.14%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 13:

3.73g (10mmol) ionic liquid [PrSPy] ⁺ pTSA ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) are put into reaction flask, stir, heating, control temperature is 80°C, reacted for 2 hours, the reaction solution was allowed to stand without stratification, and the reddish-brown solution was extracted with petroleum ether to obtain the esterification product cyclohexanol pinacol borate, which was obtained by qualitative and quantitative analysis by GC-MS. 81.37%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Implementation example 14:

Put 2.89g (10mmol) ionic liquid [PrSPy] ⁺ BF ₄ ^- and 0.62g (10mmol) boric acid and 1g (10mmol) cyclohexanol, pinacol 1.18 (10mmol) into the reaction flask, stir, heat, and control the temperature 80°C, react for 2 hours, let the reaction solution stand still, separate layers, the upper layer is a brownish yellow solution, the lower layer is an orange liquid, the esterification product cyclohexanol pinacol borate is separated by liquid separation, and it is qualitative by GC-MS , Quantitative analysis obtained a yield of 54.1%. The ionic liquid layer can be reused after being washed 2-5 times with a small amount of organic solvent, heated and vacuum-dried to remove water and organic matter.

Claims (5)

1. a synthetic method of boric acid ester is characterized in that in acidic ionic liquid, the esterification reaction of catalyzed boric acid and alcohol obtains boric acid ester; Used acidic ionic liquid adopts imidazole ionic liquid, pyridine ionic liquid or Quaternary ammonium salt ionic liquid, choose one of the following molecular structural formula substances, which are:

Wherein, the meaning of R ¹ is H or sulfonic acid propyl group; the meaning of R ² is H or sulfonic acid propyl group; the meaning of X is HSO ₄ , BF ₄ or CH ₃ COO; Described boric acid ester, its molecular structural formula is any one shown in the following:

Wherein R ³ is a kind of methyl, ethyl, propyl, isopropyl, n-butyl, n-octyl. 2. synthetic method according to claim 1, it is characterized in that described esterification reaction condition is a certain amount of acidic ionic liquid, the mixture of boric acid and monohydric alcohol or monohydric alcohol and dibasic alcohol, at room temperature～90 degree The reaction is stirred within the temperature range, and after 2 to 15 hours of reaction, the borate layer on the upper layer of the reaction system is separated, and the product is obtained by fractional distillation. 3. synthetic method according to claim 2, it is characterized in that the amount of each substance in the described esterification reaction system, for using monohydric alcohol, ionic liquid: boric acid: the mol ratio of alcohol is 0.5～10: 1: 3 ; For the use of monohydric alcohol and dibasic alcohol system, the molar ratio of ionic liquid: boric acid: monobasic alcohol: dibasic alcohol is 0.5～10:1:1:1. 4. The synthesis method according to claim 2, characterized in that the ionic liquid layer in the lower layer of the reaction system is subjected to repeated use of the ionic liquid after organic solvent extraction and washing, heating and dehydration under reduced pressure, and removal of organic matter. 5. according to the required synthetic method of claim 4, it is characterized in that described organic solvent is ether, sherwood oil, benzene, any one in toluene.