SU945156A1 - Process for producing aluminia having phosphonyl surface groups - Google Patents

Description

(Sk) METHOD FOR GETTING SILICON WITH PHOSPHONILE GROUPS ON SURFACE

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The invention relates to chemical technology, specifically to methods for producing silica with phosphonyl groups on the surface, which can be used as carrying metal complex catalysts.

A known method for producing silica with phosphonyl groups on the surface, which consists in treating silica gel dried at 150 ° C with ROCS vapors and subsequent hydrolysis with vapors without being reacted) DOES (

Ps-C1 connections

However, the product thus obtained is hydrolytically unstable, since the phosphonyl groups are easily washed with water.

A known method for producing silica containing phosphonyl groups is bonded to the surface of the silica by means of bonds.

This method is multi-stage and includes the following stages: processing of silica in the gas phase or in an organic solvent to graft vinyl groups to the surface of the silica; joining to the vinyl groups of phosphorus pentachloride by the interaction of silica in an organic solvent environment with PCI; hydrolysis of the obtained

10 compounds with water and obtaining the final product, a modified silica with phosphonyl, groups on the surface. However, after each stage, it is necessary to remove reaction by-products and residues of initial reagents. The multi-step process makes it difficult, reducing the yield of the desired reaction product.

The aim of the invention is to simplify the process for producing silica with phosphonyl groups on the surface.

This goal is achieved in that the silica is treated in the gas phase or in the medium of an organic solvent with a silicon-organic compound - dimethylchlorosilylmethylphosphonic acid dichlorohydride, followed by hydrolysis of the resulting product with water.

In addition, when processing in the medium of an organic solvent, the process is carried out at a temperature from to the boiling point of the solvent.

Moreover, when processing in the gaseous phase, the process is carried out in an isolated system at 150–200 ° C.

Toluene or its mixtures with more polar solvents (pyridine, dioxane) are used as solvents. content of the last up to 25% by volume of the mixture of solvents.

The product obtained after treatment in the liquid or in the gas phase is hydrolyzed with water to convert the acid chloride to phosphonic acid and remove the reaction by-products. As a result, hydrolytically stable acid phosphonyl groups are grafted onto the surface through a bond.

Si-s:

At the stage of silica processing with dimethylchloro silylmethylphosphonic acid dichloride in the liquid or in the gas phase, the process proceeds in two directions:

a) silica surface silanol groups interact with modifier groups to form a grafted compound

 V o

I am 1 se

SiO-SiCH.p

I si e

b surface silanol groups of silica interact with groups of Ci.-P S. modifier to form a grafted compound

io- | i-cH, sr-S

ABOUT

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At the next stage, hydrolysis of the modified silica with water or an aqueous acetone mixture results in hydrolysis of P-C1 bonds (and formation of grafted phosphonic acid), as well as hydrolysis of Si-OR - bonds, as a result of which the Si OH group is reduced on the surface. The hydrolyzed modifier is removed along with the water or with the water-acetone mixture during filtration. A. Carrying out the process in gas

phase.

Example 1. Silica gel brand: KSK in the amount of 100 g, dried at 250 C for i h, is loaded into a laboratory reactor equipped with

5 by an electric heater, 10 g of dimethylchloroxy-methylmethylphosphonic acid dichloride are introduced thereto and the reactor is cooled with liquid nitrogen. Vacuum the reactor to 0.5-0.05 mm Hg.

0 and seal the system. The reaction is carried out at 150 ° C in modifier vapors for 2 hours. After cooling the reactor, the modified silica gel is discharged into a beaker, where hydrolysis is carried out in 10.0 ml of distilled water with stirring for 1 h. The silica gel is filtered and dried at 120 C for 2 h. The phosphorus content in the resulting sample is

0 0.71 wt.%.

Measure 2. ASKG silica gel in the amount of lOOiO g, dried for 3 hours, loading. 12 g of dimethylchloro silylmethylphosphonic acid dichloride hydride are introduced into the reactor, and the reactor is cooled with liquid nitrogen. Vacuum the reactor to 0.5 mM Hg. and seal the system. The reaction is carried out for T h at 200 ° C, then the reactor is cooled, the silica gel is discharged and hydrolysis is carried out in 1000 ml of distilled water with occasional stirring. Then the silica gel is filtered off and dried at 110 C. The phosphorus content in the sample obtained is 0.60% by weight.

B. Carrying out the process in the environment of an organic solvent.

Example 3. In a laboratory reactor equipped with a stirrer, 5.0 g of pyrogenic silica grade A-300, 100 ml of toluene was charged and mixed until a homogeneous suspension was obtained. pensions. Injected with mixing

5 0.77 g of the modifier in the form of a solution in 10 ml of toluene. The reaction is carried out for 6 hours at. The sample is then washed with toluene and the excess is removed.

toluene by air drying. The modified silica is treated with 150 ml of a water-acetone mixture (10: 1) for 1 h with occasional stirring. The precipitate is decanted, filtered and dried at 110 ° C. The phosphorus content in the resulting sample is 0.8 wt.

Example C, Aerosil A-300 in the amount of 5 g is thoroughly mixed with 100 ml of toluene. While stirring continues, 0.77 g of the solution of the modifier in 10 ml of toluene is introduced and the mixture is heated for 2 hours at the boiling point of toluene. The silica is filtered off and dried from residues of toluene at. The precipitate is stirred in 250 ml of an aqueous-acetone mixture (9: 1) for 1 h, decanted, filtered and dried at 110 C. The phosphorus content in the obtained sample is 0.98.

Example 5- 5 g Aerosil-A-300 are thoroughly mixed with 100 ml of a toluene-dioxane mixture (3: 1). 0.77 g of modifier is added with stirring and the mixture is heated for 2 hours at the boiling point of the solvent. Silica is filtered off and dried from the solvent residue at 20 ° C, after which the synthesis conditions

Aerosil A-ZOO, in boiling toluene, rolls in for 3 hours.

The consumption of dimethyl chloro-silyl-methyl-ylphosphonic acid dichloride is 0.7 mmol per 1 g of SiOo From the data in the table it follows that in the first stage1 and the synthesis of modifiers it is almost completely chemisorbed on the surface of silica and is not removed from it with 250 ml of water-acetone mixture (9: 1) for 1 h, decanted, filtered and dried at. The phosphorus content in the resulting sample is 0.39% by weight.

Example 6. Aerosil A-300 in the amount of 5 g is thoroughly mixed with a 100.yl toluene-pyridine mixture (3: 1). With stirring, a solution of 0.77 g of the modifier in 10 ml of toluene is introduced and the mixture is heated for 2 hours at the boiling point of the solvent. The silica is filtered off and dried from the residue of solvents at 20 ° C. The sample is washed in 250 ml of an aqueous-acetone mixture (9: 1) for 1 h, decanted, filtered and dried at 110 ° C. The phosphorus content in the resulting sample is 0.37 wt.

The table presents the results of determining the phosphorus content in a sample of silica on various levels of synthesis. Removal of unreacted modifier residues is carried out by washing with toluene, removal of the modifier bound to the surface by hydrolytic unstable Si-0-P groups is carried out simultaneously with hydrolysis of the DEW groups when washing with a water – Cetone mixture.

The phosphorus content in the modified silica after washing with solvents at various stages of the synthesis,%

1.95

0.99

Claims (2)

0.95 ke toluene. The subsequent treatment with a water-acetone mixture (9: 1) leads to the hydrolysis of the formed x51-0-P bonds and to the removal of the hydrolysis products. The content of phospho79 pa in the sample after repeated washing with the water-acetone mixture confirms the sufficient completeness of the removal of the hydrolysis products after the first washing operation with the water-acetone mixture. in the process of modifying. The proposed method of modifying silica is technologically simple and contains only two stages of processing. The process is carried out on conventional equipment, with the removal of by-products occurring at the same time as -1. The product thus obtained possesses enhanced acidic properties and can be used as a carrier of a metal complex catalyst. Claim 1. The method of producing silica with phosphonyl groups on the surface by treating it in the gas phase or in an organic medium. Dissolving the silicon compound with subsequent hydrolysis of the obtained product with water , in order to simplify the process, dimethyl chloro or or dichloride is used as the silicon-containing compound methylphosphonic acid. . 2. The method according to claim 1, wherein the solution treatment is carried out at a temperature of from 20 ° C to the boiling point of the solvent. 3. The method according to claim 1, which is based on the fact that the processing in the slot phase is carried out at 150-200 C. Sources of information taken into account during the examination 1. A.Volkova . Malygin A.A. Koltsov S.I. Alesko.vsky V. .. B. Study of the Reaction of Phosphorus Oxychloride with Hydrated Silica.-Journal of General Chemistry, 1973, V. 43, p.724728. 2. Pavlik G.E. Surface chemical compounds with acidic functional groups on silica. Author. Cand. dis. IFH AN USSR, 1968 (prototype).