CN102516287A - Modified silane coupling agent containing hydrophobic groups difficult to hydrolyze and preparation method thereof - Google Patents

Abstract

The invention discloses a modified silane coupling agent containing a difficult-to-hydrolyze hydrophobic group and a preparation method thereof. As for the reactor, add a protonic acid as a catalyst; control the reaction pressure and temperature, react under constant stirring, add a certain amount of alcohol dropwise to the reactor until the reaction is over; filter the resulting solution; take the filtrate for decompression Distillation, control the vacuum degree and temperature until no liquid droplet distills out. The invention adopts low-priced raw materials, simplifies the reaction route, and the catalyst can be used multiple times in the reaction, and hydrophobic compounds with different substituents and different substitution degrees can be obtained according to different requirements. The reaction conditions are mild and do not require high temperature and high pressure. The modified product has a long shelf life and can be kept at room temperature for two years without deterioration. The reaction conversion rate is high and the group substitution effect is good. The modified product can be used directly. It can be used as a raw material for the preparation of other compounds.

Description

A modified silane coupling agent containing refractory hydrophobic groups and its preparation method

technical field

The invention belongs to the field of organosilane coupling agent modification, and in particular relates to a method for preparing an organosilicon compound containing a hydrophobic alkoxy group. The modified organosilane coupling agent containing a hydrophobic alkoxy group is used During the process, the hydrolysis rate can be reduced, and the generation of gel during emulsion polymerization can be reduced.

Background technique

Silane coupling agent is obtained by addition of silicon chloroform (HSiCl ₃ ) and unsaturated olefins with reactive groups under the catalysis of platinum chloride acid, followed by alcoholysis. Silane coupling agent is essentially a class of silanes with organic functional groups, which have reactive groups that can chemically bond with inorganic materials (such as glass, silica sand, metals, etc.) and organic materials (synthetic resins, etc.) Chemically bound reactive groups.

Silane coupling agent structural formula:

 

Here, n=0-3; X-hydrolyzable group; Y-organic functional group, which can react with the resin. X is usually methoxy, ethoxy, methoxyethoxy, acetoxy, etc. When these groups are hydrolyzed, they will generate silanol (Si(OH) ₃ ), and combine with inorganic substances to form siloxane . Y is vinyl, amino, epoxy, methacryloxy, mercapto or ureido. These reactive groups can react with organic substances to combine. Therefore, by using silane coupling agent, a "molecular bridge" can be built between the interface of inorganic substances and organic substances, and the two materials with different properties can be connected together to improve the performance of composite materials and increase the bonding strength.

However, for some silane coupling agents containing methoxy groups with less steric hindrance, such as γ-methacryloxypropyltrimethoxysilane (A-174), they are easily hydrolyzed in the presence of water. Forming silanol, the presence of -OH will cause a dehydration reaction between the groups to cross-link into a gel-like substance. Especially for some polymerization systems in aqueous solution such as emulsion polymerization and slurry polymerization, this gel phenomenon is more obvious. During the experiment, there are a large number of particles in the reactor wall and the reaction solution, which not only affects the reaction process , which also reduces the yield of the reaction. The above factors will lead to unstable properties of the silane coupling agent during use, and it is difficult to control the composition. Therefore, it is necessary to modify organosilicon, introduce groups with greater steric hindrance on its molecules, increase the difficulty of water molecules attacking and replacing methoxy groups, reduce the hydrolysis rate of organosilicon, and thus reduce the gel's Produce, the present invention has solved this problem well. And by controlling the degree of methoxyl substitution, the speed of emulsion polymerization can be regulated.

The schematic diagram of hydrolysis and condensation of organosilane coupling agent into gel is as follows:

 

 

In the prior art, the modification methods involving silane coupling agents include:

1) The Chinese invention patent No. 201010045841.6 discloses a class of highly heat-resistant imide aromatic heterocycle modified silane coupling agent. The imide aromatic heterocycle is introduced into the molecular structure of the silane coupling agent, which improves the heat resistance of the silane coupling agent. According to the increase in the number of imide rings and rigid structural units in the molecule, the modified silane coupling can be improved. The heat resistance of the joint agent.

2) The Chinese invention patent No. 200910144203.7 discloses a phosphorus-nitrogen-containing flame-retardant modified silane coupling agent and its preparation method. Use dichloromethane as solvent, some polyols or polyphenols as reaction matrix, add phosphorus-containing compounds to obtain white solid powder, then use tetrahydrofuran as solvent, triethylamine as acid agent, inert gas protection, add siloxane After the reaction, a phosphorus-nitrogen-containing flame-retardant modified silane coupling agent is obtained. According to the phosphorus-nitrogen synergistic flame-retardant mechanism, the problem of the silane coupling agent being flammable is solved.

Contents of the invention

Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a modified silane coupling agent containing a refractory hydrophobic group and a preparation method thereof, so that the prepared organosilicon compound containing a hydrophobic alkoxy group can During use, the hydrolysis rate can be reduced to avoid the formation of gel.

In order to achieve the above-mentioned technical purpose and achieve the above-mentioned technical effect, the present invention is realized through the following technical solutions:

The method for organosilicon compounds containing hydrophobic alkoxy groups described in the present invention can be realized through the following reaction process (the following are all illustrated by γ-methacryloxypropyltrimethoxysilane (A-174) ):

Step 1. Weigh γ-methacryloxypropyltrimethoxysilane (A-174) and alcohol (ROH) at a molar ratio of 1:3-8, and place the mixture in the reactor, and Add protonic acid as catalyst;

Step 2. Control the reaction pressure to normal pressure -0.6MP, and the temperature is 75-90°C. When the reaction is 6-24 hours under constant stirring, a certain amount of alcohol is added dropwise to the reactor every hour until the reaction is completed;

Step 3, the reaction solution is cooled to room temperature, and the resulting solution is filtered;

Step 4. Take the filtrate and carry out vacuum distillation. The vacuum degree is controlled at 500-760mmHg, and the temperature is controlled at 80-100°C until no liquid drops are distilled out to obtain the modified organosilicon compound containing hydrophobic alkoxy groups .

Further, the modified alcohol described in the present invention is one of ethanol, n-propanol, isopropanol and butanol or a mixture thereof.

Further, taking ethanol and isopropanol as examples, through this preparation method, the following organosilicon compounds with different degrees of substitution can be prepared by controlling different reaction times and types and proportions of raw materials:

The beneficial effects of the present invention are:

1. The introduction of large steric hindrance and strong hydrophobic groups into the molecule enhances the hydrophobicity of the product and avoids the problem of scrapping the product to be modified due to water-absorbing gel. The product of the invention has a long shelf life and can be kept for two years without deterioration at normal temperature;

2. Use low-cost raw materials, simplify the reaction route, and use reusable catalysts in the reaction;

3. Alcohols used for modification are ethanol, n-propanol, isopropanol and butanol. Hydrophobic compounds with different substituents and different degrees of substitution can be obtained according to different requirements, which provides conditions for the controllable reaction of the subsequent emulsion polymerization;

4. The reaction conditions are mild and do not require high temperature, high pressure, etc.;

5. The reaction conversion rate is higher, and the group substitution effect is better;

6. The product can be used directly, or it can be used as a raw material for preparing other compounds by taking advantage of the properties of other functional groups.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below. The specific embodiment of the present invention is given in detail by the following examples and accompanying drawings.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is the infrared comparison figure of modified A-174 and unmodified A-174;

Fig. 2 is the NMR spectrum of the modified A-174;

Figure 3 is the nuclear magnetic spectrum of unmodified A-174.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

Example 1

Add 50g of vinyltrimethoxysilane and 82g of n-propanol into a dry reactor, and add 1.5g of acid as a catalyst, heat up to 80°C under stirring, the pressure of the reaction system is normal pressure, connect the condensing device to collect the generated methanol, The reaction time was 6 hours, and 20 ml of n-propanol was added dropwise to the reactor every hour until the reaction was completed.

Cool the reacted mixed solution slightly, filter it through filter paper, and distill it under reduced pressure on a rotary evaporator. The vacuum degree is controlled at 600mmHg, and the temperature is controlled at 95°C to separate the generated methanol, unreacted n-propanol and vinyl trimethyl Oxysilane, can obtain the modified organosilicon compound containing n-propoxy group.

the

Example 2

Add 57g of γ-methacryloxypropyltrimethoxysilane (A-174) and 70g of isopropanol into a dry reactor, and add 1.25g of acid as a catalyst, and raise the temperature to 82°C while stirring, and the pressure of the reaction system At normal pressure, connect the condensing device to collect the generated methanol. The reaction time is 14 hours, and 35ml of isopropanol is added dropwise to the reactor every hour until the reaction is completed.

After the reaction, the mixed solution was cooled, then filtered with filter paper, and then distilled under reduced pressure on a rotary evaporator. The vacuum degree was controlled at 600mmHg, and the temperature was controlled at 90°C to separate the generated methanol, unreacted isopropanol and γ-formazol. Acryloxypropyltrimethoxysilane can be used to obtain a modified isopropoxy-containing organosilicon compound.

Referring to Figure 1, the skeleton structure of isopropanol-modified A-174 is similar to that of pure A-174. At 1636cm-1 is the characteristic peak of stretching vibration of C=C bond; at 1720cm-1 is the characteristic peak of stretching vibration of C=O; at 1166cm-1 is the characteristic peak of COC bond in ester bond; at 1088cm-1, Si-OC The skeleton vibration peak of the bond, 1455 cm-1 is the characteristic absorption peak of _-CH3 . But the difference between the two figures is that in Figure 2-2-1-1, the absorption peak of -O-CH ₃ is at 2842 cm-1. In Figure 2-2-1-2, there is an absorption peak at 1376 cm-1, indicating the presence of -CH-(CH ₃ ) ₂ ; there is no obvious characteristic absorption peak at 2842 cm-1, indicating that after modification- O- _CH3 has been well replaced by O-CH-( _CH3 ) ₂ .

As shown by the comparison of Figure 2 and Figure 3, in the unmodified A-174 spectrum, there is a single peak of about 9 hydrogens at δ=3.35, which is the hydrogen in the three -OCH ₃ methoxy groups; In 2-2-2-2, there is a singlet of about 3 hydrogens at δ=3.35, which is a hydrogen in the methoxy group of -OCH ₃ , and a doublet of about 12 hydrogens at δ=1.16, which is - The hydrogen in the methyl group in OCH(CH3) ₂ indicates that two -OCH ₃ have been successfully replaced by -OCH(CH ₃ ) ₂ .

the

Example 3

Add 69g of γ-methacryloxypropyltrimethoxysilane (A-174) and 76g of isopropanol into a dry reactor, and add 2.0g of acid as a catalyst, heat up to 81°C under stirring, and the pressure of the reaction system At normal pressure, connect a condensing device to collect the generated methanol, and the reaction time is 20 hours, and 28ml of isopropanol is added dropwise to the reactor every hour until the reaction is completed.

The reaction solution was slightly cooled, filtered through filter paper, and distilled under reduced pressure on a rotary evaporator, the vacuum degree was controlled at 600mmHg, and the temperature was controlled at 90°C to separate the generated methanol, unreacted isopropanol and γ-methacryloyloxy Propyltrimethoxysilane can be used to obtain a modified isopropoxy-containing organosilicon compound.

the

Example 4

Add 65g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 60g of isopropanol into a dry reactor, and add 1.3g of acid as a catalyst, heat up to 80°C under stirring, and the pressure of the reaction system At normal pressure, a condensing device was connected to collect the generated methanol. The reaction time was 7 hours, and 25 ml of isopropanol was added dropwise to the reactor every hour until the reaction was completed.

Cool the reacted mixed solution, filter it through filter paper, and distill it under reduced pressure on a rotary evaporator with the vacuum degree controlled at 600mmHg and the temperature controlled at 85°C to separate the generated methanol, unreacted isopropanol and N-(β -aminoethyl)-γ-aminopropyltrimethoxysilane to obtain a modified isopropoxy-containing organosilicon compound.

the

Example 5

Add 67g of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and 65g of ethanol into a dry reactor, and add 1 gram of acid as a catalyst, heat up to 79°C under stirring, and the reaction system The pressure is normal pressure, connect the condensing device to collect the methanol generated, the reaction time is 12 hours, and 18ml of ethanol is added dropwise to the reactor every hour until the reaction ends.

Cool the mixture slightly, filter it through filter paper, and distill it under reduced pressure on a rotary evaporator. The vacuum degree is controlled at 600mmHg, and the temperature is controlled at 87°C to separate the generated methanol, unreacted ethanol and N-(β-aminoethyl base)-γ-aminopropylmethyldimethoxysilane to obtain a modified ethoxy-containing organosilicon compound.

the

Example 6

Add 50g of γ-methacryloxypropyltrimethoxysilane (A-174) and 70g of butanol into a dry reactor, and add one gram of acid as a catalyst, heat up to 79°C under stirring, and the pressure of the reaction system is At normal pressure, connect the condensing device to collect the generated methanol. The reaction time is 22 hours, and 18 ml of butanol is added dropwise to the reactor every hour until the reaction is completed.

Cool the mixture slightly, filter it through filter paper, distill it under reduced pressure on a rotary evaporator, control the vacuum at 600mmHg, and control the temperature at 97°C to separate the generated methanol, unreacted butanol and γ-methacryloyloxy Propyltrimethoxysilane can be used to obtain a modified butoxy-containing organosilicon compound.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A modified silane coupling agent containing a difficult hydrolyzed hydrophobic group and a preparation method thereof, obtained by modifying the silane coupling agent with an alcohol compound, is characterized in that, comprising the following steps: Step 1. Weigh the silane coupling agent and alcohol to be modified in a molar ratio of 1:3-1:8, put the mixed solution in the reactor, and add protonic acid as a catalyst; Step 2. Control the reaction pressure to be normal pressure -0.6MPa, and the temperature is 75-95°C. When reacting for 4-30 hours under constant stirring, add a certain amount of alcohol dropwise to the reactor every 1 hour until the reaction is completed; Step 3, the reaction solution is cooled to room temperature, and the resulting solution is filtered; Step 4. Take the filtrate and carry out vacuum distillation. The vacuum degree is controlled at 500-760mmHg, and the temperature is controlled at 80-100°C until no liquid drops are distilled out to obtain the modified organosilicon compound containing hydrophobic alkoxy groups . 2. according to the described silane coupling agent and preparation method thereof of the described difficult hydrolysis hydrophobic group modification of claim 1, it is characterized in that: the alcohol of described modification is ethanol, n-propanol, isopropanol and butanol one or a mixture of several. 3. The modified silane coupling agent containing refractory hydrophobic groups according to claim 1 and its preparation method, characterized in that: the silane coupling agent is gamma-methacryloxypropyl trimethyl Oxysilane (A-174), Vinyltrimethoxysiloxane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane or N-(β-aminoethyl)-γ- Aminopropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane. 4. The modified silane coupling agent containing refractory hydrophobic groups and preparation method thereof according to claim 1, characterized in that: the catalyst used is a solid granular protonic acid with a particle diameter of about 0.1-0.9mm, The preferred particle size is 0.4-0.7mm. It is a copolymer of styrene and p-styrene sulfonic acid. After the reaction, it can be removed by filtration. The catalyst can be reused 5-6 times without other complicated operations. 5. the silane coupling agent containing modified silane coupling agent according to claim 1 and preparation method thereof, is characterized in that: the preferred reaction pressure of modified silane coupling agent is normal pressure, and the preferred reaction temperature is 80-90°C, the preferred reaction time is 8-22 hours. 6. The modified silane coupling agent containing refractory hydrophobic groups and preparation method thereof according to claim 2, characterized in that: take the filtrate and carry out vacuum distillation, preferably the vacuum degree is controlled at 580-660mmHg, preferably the temperature At 85-90°C.

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