CN1322726A - Method of preparing silicate ester directly from silicate - Google Patents

Abstract

Artificial or natural silicate as main material is first acidified with bronsted acid in alcohol at 0-30 deg.c to eliminate metal ion and then dewatered by adding strong dewatering agent to eliminate water produced during reaction to obtain silicate ester. The method of the present invention scheme can shorten reaction period to less than 5 hr and raise yield to over 70 %. The method is suitable for use in industrial production and has low production cost, high yield and no pollution.

Description

The method of preparing silicate ester directly from silicate

The invention belongs to the preparation method of silicon ester, be specifically related to method by preparing silicate ester directly from silicate.

Silicon ester is very extensive in Application for Field such as chemical novel agent, organic synthesis, glass, potteries, and preparing various silicon ester and all be with silicon-dioxide is starting raw material.Its traditional preparation method has two kinds: the one, and with SiCl ₄Method for intermediate.The 2nd, the Rochow direct synthesis technique.These two kinds of method persons will need high-intensity smelting equipment and consume lot of energy, thereby increase the cost of silicon ester product through the carbo-thermal process flow process of silicon-dioxide, have limited its development.SiO ₂Take up an area of 1/4th of ball mineral wealth, raw material is easy to get, and is cheap, therefore with the cryochemistry method chemistry of silicones frontier that silicon-dioxide directly changes into silicon ester had very tempting prospect.From Rosenheim reported first in 1931 by SiO ₂Directly since the cryochemistry method of synthesizing organo-silicon, especially since nearly ten years, the research in this field becomes increasingly active.

Cut till the present, bibliographical information use four kinds of different organic monomers with SiO ₂Change into the method for silicon ester.These four kinds of organic monomers are pyrocatechol, aliphatic diol, organic amine, gasiform methylcarbonate respectively.

1.1 Rosenheim method

This method is that Rosenheim finds, he uses silica gel and pyrocatechol in the aqueous solution of alkalescence, at room temperature reacts, and obtains containing the hexa-coordinate compound M of crystal water ₂[Si (C ₆H ₄O ₂) ₃] nH ₂O, its productive rate are 78%.

Alkali in this reaction is ammoniacal liquor (NH ₃H ₂O) or KOH, M ⁺=NH ₄ ⁺, n=9; M ⁺=K ⁺, n=8, its reaction conditions gentleness, transformation efficiency are higher.In the environment of water is arranged, SiO ₂React with pyrocatechol, what obtain is the product that contains crystal water, and A.Boudin has found that preparation does not conform to the method for the six coordinate complex of crystal water: promptly in the solution of sodium methylate/methyl alcohol, and reflux, following reaction takes place in silica gel and pyrocatechol, and transformation efficiency reaches 70%:

Complexing ion [Si (C ₆H ₄O ₂) ₃] ^2-Negative charge with 2 units, and central atom Si is surrounded by three bigger groups, on electrocharge effect and steric effect two aspects, going up the generation nucleophilic substitution reaction at the central atom Si of product (II) is the comparison difficulty, and therefore the silicon ester with (II) and protonic acid (as HCl) prepared in reaction pyrocatechol is the comparison difficulty.

2.2 Laine method one

Because title complex (II) is more stable, can only react with stronger nucleophilic reagent, be unfavorable for further conversion, in order to overcome this problem, Laine aliphatic diol (as ethylene glycol) and SiO ₂Under highly basic, react, obtain the higher pentacoordinate complex compound M of reactive behavior ₂Si ₂(OCH ₂CH ₂O) ₅, M is Na, K, Cs in this reaction, alkali also can be used alkaline-earth oxide (as MgO, CaO etc.).

In used glycol, mostly adopt the vicinal glycol.Main raw material SiO ₂, can use in theory any type of, other SiO of any level ₂This method weak point has: generate more water, at high temperature hydrolysis M in the reaction process ₂Si ₂(OCH ₂CH ₂O) ₅Alkalescence in the reaction system is strong not enough, and this two aspects factor makes that the speed of reaction is slow and productive rate is not high.Bibliographical information, though with specific surface area greater than 600m ²g ^-1Silica gel be raw material, complete reaction need be used the 1-2h time, its productive rate is 80%, uses through melting treatment, fineness is greater than 300 purpose SiO ₂, complete reaction need be used 3-6h, and productive rate also surpasses 80%, but makes starting raw material with natural siliceous sand, and even be crushed to 300-400 order fineness, complete reaction need be used the above time of 200h, and this and industrial requirement have certain distance.Laine has reported M ₂Si ₂(OCH ₂CH ₂O) ₅Generate silicon ester and oligopolymer thereof with protonic acid (as HCl) reaction, but the processing condition of not research the best.

1.3 Laine method two

Laine can obtain silazane with the alkali in the organic amine replacement aforesaid method, and in heat-processed, condensation reaction can take place silazane, and product is an oligopolymer.As do close dose with ethylene glycol, be heated to

The ethylene glycol boiling, trolamine and SiO ₂Following reaction takes place:

This method requires the boiling point of organic amine higher, at least than the boiling point height of ethylene glycol.Normally used organic amine is polyamines or amino alcohol, because this class amine has stronger alkalescence, makes reaction be easy to carry out.

1.4 gas-solid phase reaction synthetic method

The Japan scholar utilizes gas-solid phase reaction directly to wait SiO ₂Change into methyl silicate Si (OMe) ₄, this method is: under 500K-600K, the gasiform methylcarbonate by with alkaline silica gel, is obtained product methyl silicate Si (OMe) ₄, the reaction times, its productive rate surpassed 90% in 1 hour.

This reaction conversion ratio is higher, and speed of response is very fast, product S i (OMe) ₄With unreacted SiO ₂Easily separated.But this method also has weak point: at first, it only can use the carbonic ether of lower alcohol to make raw material, this is because the carbonic diester gasification temperature of higher alcohols is too high, need high strength equipment and consume lot of energy, and the gasification temperature of the carbonic diester that has is too high, just do not decompose before reaching gasification, the mechanism of gas-solid phase reaction is RO in addition ^-The Si-O-Si key on attack silica gel surface, and the RO of higher alcohols ^-Activity is lower.

More than be up to now bibliographical information directly by SiO ₂Four kinds of methods of preparation silicon ester.In addition, Kenney and Goodwin directly synthesize tetraethoxy with silicate.Silicate is earlier with protonic acid (as HCl) acidifying, mix azeotropic in the solvent at toluene and alcoholic acid then, slowly boil off the water that produces in the reaction process, but since this method get rid of water that reaction generates inadequately rapidly, thorough inadequately, so final product is the miscellany of the end polymers of tetraethoxy, triethoxy silanol and tetraethyl silicate.And productive rate is the end of than, generally between 30%-50%.

In addition, Kcnny etc. reported that they adopted the protonic acid acidifying with the direct synthetic silicic acid ester of silicic acid in 1988, dewater with toluene, ethanol and water azeotropic method in the back, productive rate reaches 70%, but its final product is positive tetraethyl orthosilicate and its dimer, tripolymer, tetrameric mixture.

The object of the present invention is to provide a kind of method, to overcome the deficiency of above-mentioned each method by preparing silicate ester directly from silicate.

By the method for preparing silicate ester directly from silicate, it is to be main raw material with synthetic or natural silicate, at first uses the protonic acid acidifying in alcohol, removes metal ion, and souring temperature is controlled at 0 ℃～30 ℃; Fully react the back at it and add strong dewatering agent, remove the water that generates in the reaction process, obtain silicon ester.

Silicate is selected water glass, Calucium Silicate powder, monticellite, willemite stone, calcium magnesium feldspar or rankinite.Dewatering agent is selected thionyl chloride, diacetyl oxide, acetate chlorine or molecular sieve.Alcohol selects methyl alcohol, ethanol, propyl alcohol, with propyl alcohol or butanols, protonic acid is selected thionyl chloride, hydrochloric acid or sulfuric acid.

The method that this technical scheme proposes has not only shortened the reaction times greatly, and the reaction times was controlled in 5 hours, and had improved productive rate by a relatively large margin, and productive rate is more than 70%.This method is easier to suitability for industrialized production, and production cost is low, and the productive rate height is pollution-free.

Embodiment 1:

Prepare tetraethoxy by wollastonite (Calucium Silicate powder): silicate is selected Calucium Silicate powder, and alcohol is selected ethanol, and protonic acid is selected thionyl chloride, dewatering agent selection thionyl chloride, and the mass ratio of four kinds of raw materials is 1: 25～56: 2: 1.5～3.

To capacity is that to add the wollastonite, the 800ml that contain pure Calucium Silicate powder 25 grams in the three-necked flask of 1L heavily be 630 gram ethanol and 7.8 gram water, ice bath, and slowly dripping 32ml under the mechanical stirring heavily is 53 gram thionyl chloride SOCl ₂, dropwise the back and stir 4h, filter, keep filtrate, add hot filtrate then to boiling, the limit steams the solvent limit, and to drip 65ml lentamente heavily be 108 gram thionyl chloride SOCl ₂, last underpressure distillation obtains product 31.2 grams, and productive rate is 70%.

Detected result: infrared spectra IR:V _Max/ cm ^-1: 1044 (Si-O), 2980,2800,1500 (CH ₃), 2930,1400,800 (CH ₂-); Nuclear magnetic resonance spectrum ¹HMR δ: 1.12～1.5 (12H ,-CH ₃), 3.87～4 (8H ,-CH ₂-).

Embodiment 2:

Prepare tetraethoxy by bubble flower alkali.Silicate is selected water glass, and alcohol is selected ethanol, and protonic acid is selected hydrochloric acid, and dewatering agent is selected thionyl chloride, and the mass ratio of four kinds of raw materials is 1: 10～20: 1: 3～5.

To capacity is to add the bubble flower alkali that contains pure water glass 36 grams, the ethanol of 515 grams, ice bath in the three-necked flask of 1L, under the mechanical stirring, with 36 gram hcl acidifyings, reaction 5h after-filtration, add then hot filtrate to the boiling, the limit steam the solvent limit drip lentamente 85ml heavily be 141 the gram SOCl ₂, last underpressure distillation obtains product 29.6 grams, and productive rate is 81%.

Detected result:

Infrared spectra IR:V _Max/ cm ^-1: 1050 (Si-O), 2950,2800,1500 (CH ₃), 2900,1400,750 (CH ₂-); He Ci resonance spectrum ¹HMR δ: 1.22 ∽ 1.56 (12H ,-CH ₃), 3.63,4.5 (8H ,-CH ₂-).

Claims (6)

1, a kind of method by preparing silicate ester directly from silicate, it is to be main raw material with synthetic or natural silicate, at first uses the protonic acid acidifying in alcohol, removes metal ion, souring temperature is controlled at 0 ℃～30 ℃; Fully react the back at it and add strong dewatering agent, remove the water that generates in the reaction process, obtain silicon ester.

2, according to claim 1 by the method for preparing silicate ester directly from silicate, silicate is selected water glass, Calucium Silicate powder, monticellite, willemite stone, calcium magnesium feldspar or rankinite.

3, according to claim 1 by the method for preparing silicate ester directly from silicate, dewatering agent is selected thionyl chloride, diacetyl oxide, acetate chlorine or molecular sieve.

4, according to claim 1 by the method for preparing silicate ester directly from silicate, alcohol selects methyl alcohol, ethanol, propyl alcohol, with propyl alcohol or butanols.

5, according to claim 1 by the method for preparing silicate ester directly from silicate, it is the preparation tetraethyl silicate, and silicate is selected water glass, alcohol is selected ethanol, protonic acid is selected thionyl chloride, and dewatering agent is selected thionyl chloride, and the mass ratio of four kinds of raw materials is 1: 25～56: 2: 1.5～3.

6, according to claim 1 by the method for preparing silicate ester directly from silicate, it is the preparation tetraethyl silicate, and silicate is selected Calucium Silicate powder, alcohol is selected ethanol, protonic acid is selected hydrochloric acid, and dewatering agent is selected thionyl chloride, and the mass ratio of four kinds of raw materials is 1: 10～20: 1: 3～5.