JPH03170529A - Production of metal-coordinatable organosilicon polymer - Google Patents

Abstract

PURPOSE:To prepare the title polymer contg. a large amt. of metal ion- coordinatable groups and having an excellent metal ion-scavenging ability by hydrolyzing and condensing a specific metal ion-coordinated alkoxysilane, compd. and removing the metal ion. CONSTITUTION:A metal ion-coordinated alkoxysilane compd. obtd. by coordinating a metal ion (e.g. Cu ion) with a metal ion-coordinatable alkoxysilane compd. of the formula (wherein R<1> is an org. group contg. a metal ion-coordinatable group; (n) is 1-3; R<2> is an org. group contg. a metal ion-non-coordinatable group; and (m) is 0-2) (e.g. gamma-aminopropyltrimethoxysilane) is hydrolyzed and condensed, and the metal ion is removed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the adsorption and separation of metal ions. This invention relates to a method for producing metal-coordinating organosilicon polymers used for concentration and the like.

[Prior Art J] Inorganic porous bodies with large surface areas such as silica gel and porous glass with metal ion coordinating functional groups introduced onto the surface are used as substances, catalysts, and the like.

A widely used method for introducing metal-coordinating functional groups is through covalent bonding with the polymer surface. For example, it is reported in "Surface", Vol. 27, No. 360, that the surface of silica gel is modified by applying trialkoxysilane having various metal-coordinating functional groups to the silica gel to give it the ability to separate various metal ions. Page (written by Kikuo Terada)
It is described in. Also, (Meal ssl (CH
The use of rhodium-osmium mixed clusters supported on silica gel surface-treated with gl-PPhi as a catalyst for hydrogenation of ethylene and isomerization of butene was reported in "Surface", Vol. Written by Masaru Ichikawa). However, when metal coordinating functional groups are introduced by these methods, the amount introduced per unit weight of silica gel is small, and the metal ion adsorption ability of the resulting product is not sufficient.

In order to increase the amount of metal-coordinating functional groups introduced, it is necessary to finely crush the carrier to be treated to increase its surface area. However, fine powders with a large surface area have high surface activity, making handling and storage complicated and troublesome. [Problems to be Solved by the Invention] In order to solve such problems, the present inventors have discovered that organosilicon polymers produced by a sol-gel method using an alkoxysilane compound as a starting material are generally hydrophilic and porous. In view of the fact that the sol-gel method is a solid substance ("Science of sol-gel method, published by Agne Seifusha, 1988, written by Masao Sakuhana, pp. 28-35), sol-gel can be produced directly from an alkoxysilane compound having a metal ion coordinating functional group. We attempted to synthesize metal ion-coordinating organosilicon polymers by this method.

Organosilicon polymers produced from this alkoxysilane compound by the sol-gel method have high wettability with solutions.
Since it is expected to have a high mass transfer rate, we thought that it would be a metal ion adsorbent with excellent adsorption ability. However, as shown in the examples below, the metal ion extraction rate was extremely low. The inventors considered the cause of this as follows. In other words, organosilicon polymers synthesized by the conventional sol-gel method are macroscopically porous. However, in order to coordinately adsorb metal ions, it is necessary that the metal ion coordinating functional group forms a certain coordination space, and the organosilicon polymer has that coordination space. I haven't. Therefore, an object of the present invention is to produce an organosilicon polymer capable of coordinating and introducing a metal coordinating functional group at a high introduction rate by improving the method for producing an organosilicon polymer.

[Means for Solving the Problem] In order to achieve the object, the present invention provides a metal ion represented by the formula (R')fi(R'').Sx(OR]4-11-1 ・(1) After previously coordinating a metal ion to a coordinating alkoxysilane compound and subjecting the obtained metal ion-coordinating alkoxysilane compound to hydrolysis-condensation treatment,
It is characterized by removing the metal ions. Further, a metal-coordinating organosilicon polymer can also be produced from a system in which the compound of the above formula (1) is mixed with the compound of the following formula (2) through a similar process.

(R”)t SifORli-g * m j @
(2) [Function] In the present invention, a metal ion is coordinated in advance to an alkoxysilane compound having a metal ion coordinating functional group, and then the alkoxysilyl group is hydrolyzed and polycondensed to form a polymer by a sol-gel method. Finally, metal ions are removed from the polymer by chemical treatment such as acid treatment. According to this method, a metal ion coordination environment is formed in advance through a complexing treatment and then a polymerization treatment is performed, so that the synthesized organosilicon polymer has a fixed metal ion coordination space inside it. ．． In addition to this unique state, the mass transfer rate is high due to the porous structure that is a characteristic of the sol-gel method, and the obtained organosilicon polymer is thought to exhibit a high metal ion trapping effect. The metal-coordinating alkoxysilane compound used in the present invention is not particularly limited as long as it has the structure of the following formula. Formula [R')-(R"l- Si(ORI<----
"" fil However, R1 represents an organic group having a metal ion coordinating group, and R is methyl, ethyl, proyl,
Indicates a hydrolyzable lower alkyl group such as butyl, acetoxy, acetylacetonate, etc. Further, n is an integer of 1 to 3, and when n is 2 or 3, the organic groups R' may be the same or different. Further, R2 is an organic group having a metal ion non-coordinating group, and m represents an integer of 0 to 2. Specifically, the following metal-coordinating alkoxysilane compounds are listed as relatively easily available. Nitrogen-containing type -Me01sSi-CHi)i-NHz, (EtO)
sSi-(CH*)s-Nut,MeOlsSi-C
H* s-NHMe, Meal sSi- (CH*l
．． -NH-CH*CH=CHMeal mSi- (
CH mountain-NH-cut0Meal sSi- CH. +
1-NHOMeal sSi- (CHx) s-N
HφMeO sSi- CHm s-NMe*MeO
sSi-CHx s-NEtvMeO]sSi-C
H* 4-NHIMeO sSi- Hz ++-N
HzNeo) xsi-C:>N}lg Eto) -Si-C>NHI EtOl sSi- fcHi) s-] z-NHM
eO ssi-CH*-NH-CHzCHz-NHxM
en) *si- (CH.l.-NH- ELI
1-NH*Meal ssi- fcH. l s-NH
- (cHrl @-NH.(Meal sSi- (
CH. )1(}CHs-Nl{- (cHal z-N
Ht(Meal sSi- (CH*l s-NH-
(CH*l x-NH- (CHx) .-Si (O
Mel sfMe01 sSL- (CH.) s-N
H- (CH.) t-NH- (CHz) *-NH
*(Meal -Si- (CHz) *-CN(Et
a) sSi-(CHxl x-CN(Meal s
Si- fcH*l s-CM[EtO) sSi-
(CHJ s-CN(Eto).si- (cHt)
*eC}lx-CN(Et01 sSi- (CHil
s-NHC (01 NHt(Et01 sSL-
(CH*l s-NHC fol N}ICHMeφ-nitrogen and oxygen-containing type-fEto) sSi- (CHx) s-N (CHz
CHxOHl m(Eta) sSi-CH”CHCM
e*-0- (CHJ s-NH! Mononitrogen and sulfur containing type (Eta) xSi- (CL) t-S-C}IxC
HJHt-oxygen-containing type (EtOl sSl- (CHzl s-CH (CO
OEt) s(Et01 sSi- (CH-) s-
NHC (ol eCOOH-phosphorus-containing type 1 (Et01 -Si- (CH*) *-P sulfur-containing type 1 fMe01 xsi-CH.-SH (Men) *Si- (CHt) s-S}I(Et
O] sSi- (CL) 3-SH(Meal sS
i- (CHJ s-S-CH*CH"CHx-heterocyclic type one (Meal sSi- (CHxl me(Me01
xSl-(CHxl"Q(Meal sSi-(
CHil zcNfMeo) 3Sl- fcHxl
g -0(Meal sSi- ((:Hxl s-○
(Et01 xSi- (CHa) s-^(Men)
aSi- (CHa). -NO Among these metal-coordinating alkoxysilane compounds, those compatible with Class 81 of the metal ion to be collected are selected. At this time, the metal ion coordinating alkoxysilane of formula (11) may be one that undergoes hydrolysis and polycondensation as long as it is dissolved in the solvent used in the next complexing process. A solution in which a positional alkoxysilane compound is dissolved or dispersed is prepared, and a predetermined amount of a metal salt solution containing the metal ions to be collected is added to this solution. Examples of metal salts include halides, nitrates, sulfuric acid, etc. There are salts, carboxylic acid salts, etc. At this time, the solvent is not particularly limited, but hydrophilic solvents such as water, alcohol, and tetrahydrofuran are recommended from the viewpoint of solubility for both the alkoxysilane compound and the metal salt. The presence or absence of complexation of metal ions with the alkoxysilane compound can be easily recognized by the color development of the mixed and added solution.The complexation reaction proceeds instantaneously in terms of 1M. Depending on the situation, it is also possible to heat-treat the mixed additive solution.After the complexation reaction, the alkoxysilane compound is subjected to a hydrolysis/polycondensation reaction to form a polymer.This reaction It can be carried out using a solution of the compound as it is, or it can be carried out using a metal-coordinating alkoxysilane compound after distilling off the solvent.For example, alkoxysilyl group SiOR
A sufficient amount of water is added for hydrolysis, and the hydrolysis is allowed to proceed under the addition of a catalyst. The catalysts used here include mineral acids such as hydrochloric acid and sulfuric acid, carboxylic acids such as acetic acid,
Ammonia, amine. There are basic substances such as sodium hydroxide. Hydrolysis and polycondensation reactions can be further accelerated by heat treatment. After hydrolysis and polycondensation reactions, metal-coordinating organosilicon polymers are obtained in the form of precipitates or gels. When a precipitate is precipitated from the solution, the precipitate is collected by filtration and heated to remove the solvent and the like. In this way, the desired organosilicon polymer is obtained in powder form.

Next, the powdered metal ion-coordinating organosilicon polymer is immersed in a dilute mineral acid aqueous solution such as dilute hydrochloric acid. This removes the metal ions coordinated to the organosilicon polymer. The progress of this demetallation ion can be confirmed by the decolorization or whitening of the organosilicon polymer. It is possible to accelerate the demetal ion reaction by exchanging the mineral acid aqueous solution or applying heat treatment during the demetal ion process. The metal-coordinating organosilicon polymer thus obtained is finally collected by filtration and dried. In addition, in order to adjust the crosslinking density of this metal-coordinating organosilicon polymer,
It is also possible to prepare a solution by adding the compound of the following formula (2) to the compound of the preceding formula (1), and then subject the solution to the same treatment. (R2)eSi(OR)4-1...(2)
R2 in formula (2) is methyl. Ethyl, proyl, butyl, octyl, octadecyl, phenyl, naphthyl, fluoroalkyl. Vinyl, allyl, γ-chlorobrovir, γ-glycidoxybrovir, γ-methacryloxyprovir, etc. Furthermore, or in place of the compound of formula (2), a metal alkoxy compound M (
ORI, silica sol, alumina sol, etc. can be added in combination. Note that there are no restrictions on the metal element M that can be added to Si, and most of the elements M are alkoxy compounds. However, since metal alkoxy compounds other than Sf are highly hydrolyzable, if this compound is added alone, it may form a precipitate. In such a case, it is preferable to prepare an adduct by mixing a predetermined amount of the compound of formula (1) and a metal alkoxy compound in advance before preparing the solution, and use this as the raw material. [Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

-Example 1- γ-Aminoprobyltrimethoxysilane [NHt(CI-)-
SifOCHals] 10 parts by weight were dissolved in 100 parts by weight of methyl alcohol, and 35 parts by weight of a methyl alcohol solution of CuCβ2 (5% by weight) was added thereto. After stirring the solution at room temperature of 20° C. for 2 hours, methyl alcohol was separated by distillation under reduced pressure to prepare a blue alkoxysilane solution coordinating copper ions. 25 parts by weight of this copper ion alkoxysilane solution was dissolved in 50 parts by weight of methyl alcohol, and the resulting solution had 0. I
10 parts by weight of N aqueous ammonia was gradually added. This caused the solution to gel.

Therefore, when this was placed in a vacuum dryer and heat treated at 150°C for 3 hours, a blue powder was obtained. When this blue powder was immersed in an IN hydrochloric acid aqueous solution and stirred for 1 hour, the blue color of the powder disappeared. At this time, the IN hydrochloric acid aqueous solution was replaced three times. Then, the mixture was finally filtered and dried to produce a white aminobrovir organosilicon polymer.

The metal ion adsorption performance of the synthesized aminobrovir organosilicon polymer was measured by the following method.

First, aminobrovir organosilicon polymer 0. 1 part by weight was immersed in 100 parts by weight of a 1% by weight CuCβ2 aqueous solution, left for one day and night, and filtered. It was collected, washed with water, and dried.

Then, the copper ion collection rate of the treated organosilicon polymer was measured using an XIa photoelectron spectrometer ESCA.

As a result, it was found that copper ions were adsorbed at an atomic ratio of 20% to the SL atoms in the organosilicon polymer. Comparative Example 1 - 25 parts by weight of γ-aminobrobyltrimethoxysilane was dissolved in 50 parts by weight of methyl alcohol, and 0.5 parts by weight was dissolved in it. IN aqueous ammonia was added. Thereafter, an organic silicon polymer was synthesized in the same manner as in Example 1. When the copper ion collection rate of the obtained organosilicon polymer was measured by the same test method as in Example 1, the adsorption amount of copper ions was found to be below the detection limit (0
．． 01%) or less.

Example 2 - As a metal ion coordinating alkoxysilane compound, N-
A metal-coordination organosilicon polymer was synthesized in the same manner as in Example 1, except that (β-aminoethyl)-γ-aminopropyltrimethoxysilane and FeCJ2s were used as the metal salt. The O. 1 part by weight, 1
After being immersed in 100 parts by weight of an aqueous solution of F e C 12 m at % by weight and left for one day and night, the iron ion collection rate was measured by treating in the same manner as in Example 1. As a result, it was found that iron ions were adsorbed at an atomic ratio of 25% to the Si atoms in the organosilicon polymer. Comparative Example 2 - 25 parts by weight of N-(β-aminoethyl)-γ-aminoprobyltrimethoxysilane was dissolved in 50 parts by weight of methyl alcohol, and 0.0% of the solution was dissolved in 50 parts by weight of methyl alcohol. IN aqueous ammonia was added. Thereafter, an organic silicon polymer was synthesized in the same manner as in Example 1.

The iron ion collection rate of the obtained organosilicon polymer was determined in Example 1.
When measured using the same method as 2 and 2, the adsorption amount of iron ions was 1%. Example 3 - As a metal ion coordinating alkoxysilane compound, 2-
Yellow palladium ion-coordinated -2-(diphenylphosifino)ethyltriethoxysilane was synthesized in the same manner as in Example 1 using NaPdCI24 as the metal salt.

10 parts by weight of methyltriethoxysilane was added to 30 parts by weight of this palladium-coordinated alkoxysilane, dissolved in 60 parts by weight of methyl alcohol, and 0.5 parts by weight was added to this palladium-coordinated alkoxysilane. 15 parts by weight of IN aqueous ammonia was gradually added. Thereafter, heat treatment was performed in the same manner as in Example 1, followed by depalladium treatment to obtain a powdery white phosphinoethyl organosilicon polymer. 0.1 part by weight of the phosphinoethyl organosilicon polymer thus synthesized was mixed with 1% by weight of NaPdCI2. aqueous solution 100
Immersed in the weight part. Thereafter, the palladium ion collection rate of the phosphinoethyl organosilicon polymer was measured by processing in the same manner as in Example 1. As a result, it was found that palladium ions were adsorbed in an atomic ratio of 18% to Si atoms in the organosilicon polymer. Comparative Example 3 - 30 parts by weight of 2-(diphenylphosphino)ethyltriethoxysilane and 10 parts by weight of methyltriethoxysilane were dissolved in 60 parts by weight of methyl alcohol, and O. l
15 parts by weight of N aqueous ammonia was gradually added. Thereafter, an organic silicon polymer was synthesized in the same manner as in Example 1.

When the palladium ion collection rate of the obtained organosilicon polymer was measured in the same manner as in Example 3, the adsorption amount of palladium ions was below the detection limit (0.01%). [Effects of the Invention] As explained above, in the present invention, since the alkoxysilane compound that has previously formed a metal ion coordination environment through complexing treatment is polymerized, a predetermined metal ion coordination space is created inside. A fixed organosilicon polymer is synthesized. As a result, it is possible to introduce metal-coordinating functional groups at an extremely high introduction rate, and the resulting organosilicon polymer has an extremely excellent ability to trap metal ions. This organosilicon polymer is used in a wide range of applications such as adsorbents, separation membranes, concentration membranes, and ion exchangers due to its excellent performance.

Claims (1)

[Claims] Formula (R^1)_n(R^2)_mSi(OR)_4_-
_n_-_m [However, R^1 is an organic group having a metal ion coordinating group, n is an integer from 1 to 3, and when n is 2 or 3, the organic groups R^1 are the same or different. Either is fine. R^2 is an organic group having a metal ion non-coordinating group, and m is an integer of 0 to 2. ] After previously coordinating a metal ion to the metal ion-coordinating alkoxysilane compound represented by and subjecting the obtained metal ion-coordinating alkoxysilane compound to hydrolysis/condensation treatment,
A method for producing a metal ion-coordinating organosilicon polymer, the method comprising removing the metal ions.