JPH0221942A - Production of carbonaceous adsorbent - Google Patents

Abstract

PURPOSE:To obtain the title adsorbent useful as a column packing material by heat-treating a porous spherical polymer obtained from the divinylbenzene, polystyrene, polymerization catalyst, and dispersion medium as the starting material under specified conditions, and calcining the product. CONSTITUTION:Divinylbenzene, polystyrene, polymerization catalyst, and a dispersion medium are mixed, and polymerized at 60-80 deg.C to produce a carbonaceous adsorbent useful as the column packing material to be used for high-temp. gel permeation chromatography. The spherical product is separated from the obtained dispersion, and then the remaining polystyrene part is washed away with a solvent such as benzene and removed to obtain a porous spherical polymer. The polymer is heated in an oxidizing atmosphere at a rate of 5-50 deg.C/hr, held at 250-380 deg.C, then heated in an inert atmosphere or in vacuum at a rate of 50-400 deg.C/hr, and then calcined at the final temp. of >=500 deg.C. By this method, an adsorbent having excellent resistance to heat and chemicals is obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing a carbonaceous adsorbent, and more specifically to a method for producing a carbonaceous adsorbent, and more specifically, a method for manufacturing a carbonaceous adsorbent, and more specifically, a method for manufacturing a carbonaceous adsorbent, and more specifically, a method for manufacturing a carbonaceous adsorbent, and more specifically, a method for manufacturing a carbonaceous adsorbent. The present invention relates to a method for producing a carbonaceous adsorbent useful as a carbonaceous adsorbent, especially as a column filler for high-temperature GPC.

[Prior Art and Problems to be Solved by the Invention] Conventionally, 0DS-silica-based packing materials have been mainly used as column packing materials because they allow good separation of samples; In addition, under conditions exceeding about 120°C, the side chains detach and lose their function as a filler, making them unusable. was also not sufficient.

In addition, highly porous crosslinked spherical polymers are often used as column packing materials for HPLC and GPC, but they swell with solvents and change in volume, and they also have poor heat resistance. 140～
The usage limit (for high temperature GPC) was 150°C, which was still not sufficient.

In view of the current situation, the present invention provides a method for HPLC, GPC, etc. that provides good separation of samples, has sufficient strength as a column packing material, has excellent chemical resistance and heat resistance, and does not cause volume changes due to solvents. The object of the present invention is to provide a method for producing an adsorbent useful as a column packing material, etc.

[Means for Solving the Problems] The above object of the present invention is to heat-treat a porous spherical polymer obtained using divinylbenzene, polystyrene, a polymerization catalyst, a dispersion medium, etc. as starting materials under certain conditions, and then calcinate it. This is achieved by

That is, the present invention provides divinylbenzene, polystyrene,
A polymerization catalyst and a dispersion medium are used as starting materials, and these are mixed, a polymerization reaction is carried out at 60 to 80°C, a spherical product is separated from the obtained dispersion, and the residual polystyrene portion is removed using a solvent to form a porous spherical product. A polymer was obtained and heated to 250-3 in an oxidizing atmosphere at a heating rate of 5 to 50°C/hr.
Production of a carbonaceous adsorbent characterized by maintaining the temperature at 80°C, then raising the temperature at a rate of 50 to 400°C/hr in an inert atmosphere or vacuum, and firing at a final treatment temperature of 500'C or higher. It's in the method.

In the production method of the present invention, divinylbenzene, polystyrene, a polymerization catalyst, and a dispersion medium are used as starting materials, and the mixing ratio of each is 35 to 60% by weight of divinylbenzene, 5 to 10% by weight of polystyrene, and 5 to 10% by weight of polystyrene in the total amount of starting materials. Polymerization catalyst 0. L~2.0% by weight, dispersion medium 30~70
Preferably, it is % by weight.

Further, in the present invention, in addition to these components, it is preferably employed to add at least one of styrene, ethylvinylbenzene, or a toluene-soluble portion of pitch as an optional component. Addition of these components improves the yield. The amount of these components added is preferably 15% by weight or less based on the total amount of starting materials.

The polystyrene used as a starting material preferably has a molecular weight of tens of thousands to several million, and within this range the desired carbonaceous adsorbent can be obtained satisfactorily.

The polymerization catalyst may be any catalyst as long as it can successfully carry out the polymerization reaction described below, and includes peroxides such as benzoyl peroxide, with benzoyl peroxide being particularly preferred.

Further, the dispersion medium may be any dispersion medium as long as it can disperse the starting materials well and the polymerization reaction can be carried out well, and an aqueous polyvinyl alcohol solution is particularly preferred.

The toluene-soluble portion of pitch added as an optional component is a toluene-soluble portion of pitch selected from petroleum pitch, coal pitch, and the like.

In the production method of the present invention, first, a starting material such as divinylbenzene or a predetermined amount of styrene or the like is mixed and stirred to carry out a polymerization reaction. The conditions for this polymerization reaction are preferably 60-80'C11-15 hours, and emulsion polymerization is preferred as the polymerization form.

Next, after separating the spherical product from the dispersion obtained by the polymerization reaction, the remaining polystyrene portion is washed away with a solvent such as benzene or xylene to obtain a porous spherical polymer.

After drying the porous spherical polymer thus obtained, it is heated to 250 to 380°C at a rate of 5 to 50°C/hr in an oxidizing atmosphere such as air or oxygen. ，
Hold for 100 hours or less.

Furthermore, in the production method of the present invention, the porous spherical polymer heat-treated in this way is heated at a temperature increase rate of 50 to 4 in an inert atmosphere such as nitrogen gas or argon gas or under vacuum.
The temperature is increased at a rate of 00° C./hr, and the final treatment temperature is 500° C. or higher, preferably 2000° C. or higher, to obtain a carbonaceous adsorbent in the form of porous carbonaceous spheres.

As described above, the physical properties such as the particle size and pore size of the carbonaceous adsorbent, which is a porous carbonaceous sphere obtained in the production method of the present invention, are determined by the starting materials used, their blending ratio, polymerization reaction conditions, heating conditions, Adjustment is possible by arbitrarily selecting firing conditions and the like.

[Example] Hereinafter, the present invention will be explained in more detail based on Examples and Comparative Examples.

Example 1 700 g of divinylbenzene from which the polymerization inhibitor was removed in advance,
100 g of polystyrene with a molecular weight of approximately 1.8 million and 3.5 g of benzoyl peroxide as a polymerization catalyst were added, and the mixed starting materials were mixed with polyvinyl alcohol (degree of polymerization: 2000).
10% aqueous solution 700g 1::suspended, 250pp
The polymerization reaction was carried out at 8 [1'C] for 3 hours while stirring at 100 m.

After separating the spherical product from the resulting dispersion, the remaining polystyrene portion was dissolved with benzene in an ultrasonic bath and removed by washing to obtain a porous spherical polymer.

After drying this porous spherical polymer, spread it thinly on a stainless steel vessel to a thickness of about 1 mm, and spread it at a speed of 1.0 m/s.
Heat treatment was carried out by increasing the temperature from 100°C at a rate of 15°C/hr under air circulation, and holding the temperature at 280°C for 1 hour.

Furthermore, the heat-treated porous spherical polymer was transferred to a porcelain dish, spread thinly to a thickness of about 5 mm, and heated to 1000°C at a heating rate of 200°C/hr in a nitrogen atmosphere. The mixture was held for 1 hour, then transferred to a graphite crucible and heated to 2000°C at a heating rate of 400°C/hr under vacuum.
The carbonaceous adsorbent in the form of porous carbonaceous spheres was obtained by raising the temperature to 100% and holding it for 15 minutes to cause sintering.

The particle size of the obtained carbonaceous adsorbent was 5 to 20 μm, and the yield was 13%.

This was classified in methanol and the particle size was 15±2μ.
After aligning the column to 4 mm, it was wet-packed into a 4φ x 250 mmJ stainless steel column and attached to an HPLC device. After stabilizing the column using tetrahydrofuran (THF) as the eluent, the elution time of standard polystyrene having different molecular weights was measured under the following conditions. The results are shown in FIG.

(Measurement conditions) Flow rate 1. OId! /min detector
RI Temperature: 22°C Pressure: 20 K'J/cni As is clear from Figure 1, the carbonaceous adsorbent obtained in Example 1 was able to effectively separate polystyrenes of different molecular weights when used as a column packing material. It is possible to do so.

Example 2 A carbonaceous adsorbent was obtained in the same manner as in Example 1 except that the polystyrene used had a molecular weight of approximately 100,000, and a 4φX
Wet-packed into a 250 mmJ stainless steel column and
It was attached to a PLC device. Eluent: methanol/water = 8
After stabilizing the column as a 0/20% mixed solution, a mixture of aromatic compounds (1: dimethyl phthalate, 2: diallyl phthalate, 3: di-n-butyl phthalate) was prepared under the following conditions. Separation was performed. The resulting HPL
A C chart is shown in FIG.

(Measurement conditions) Flow rate 1-0 m/min Detector UV (254 nm) Temperature 25°C Pressure 90 Kg/ctj As is clear from Figure 2, the carbonaceous adsorbent obtained in Example 2 was By using the compound as an agent, it is possible to effectively separate each of the aromatic compounds mentioned above.

Example 3 700 g of divinylbenzene from which the polymerization inhibitor was removed in advance,
100 g of polystyrene with a molecular weight of approximately 1.8 million, petroleum pitch manufactured by Ashland (trade name = Aerocarb)
50 g of toluene-soluble matter and 3.5 g of benzoyl peroxide as a polymerization catalyst were added, suspended in 800 g of a 10% aqueous solution of polyvinyl alcohol (degree of polymerization: 2000), and treated with porous carbonaceous spheres in the same manner as in Example 1. When a certain carbonaceous adsorbent was obtained, the particle size of the obtained carbonaceous adsorbent was 5 to 25 μm, and the yield was 20%, compared to Example 1 in which the toluene-soluble portion of pitch was not added to the starting material. The yield was excellent.

In addition, when the elution time of standard polystyrene with different molecular weights was measured in the same manner as in Example 1 using the carbonaceous adsorbent obtained in this way, the same results as shown in Figure 1 were obtained. Polystyrene could be separated well.

Comparative Example 1 A porous spherical polymer obtained in the same manner as in Example 1 was heated to 1000°C at a heating rate of 200°C/hr in a nitrogen atmosphere without heat treatment and held for 1 hour. The spherical polymer melted during the process and became liquid-phase carbonized, and did not retain its initial particle shape.

[Effects of the Invention] As explained above, the carbonaceous adsorbent obtained by the production method of the present invention can be used as a sample as a column packing material used in HPLCSGPC etc. by arbitrarily controlling its particle size, pore size, etc. It is possible to perform the separation well.

In addition, since the carbonaceous adsorbent obtained by the production method of the present invention is carbonaceous obtained by calcination, it has sufficient strength as a column packing material, has excellent heat resistance and chemical resistance, and is resistant to solvents. Since it does not cause a change in volume, it is suitably used as a column packing material used in HPLC, GPC, etc.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the molecular weight of polystyrene and elution time according to an example (Example 1) of the present invention, and Figure 2 is a graph showing the relationship between the molecular weight and elution time of polystyrene according to an example (Example 2) of the present invention. Figure 2 is an HPLC chart of compound mixtures (1-3). 1: Dimethyl phthalate, 2: Diallyl phthalate, 3: Di-n-butyl phthalate. Patent applicant: Nippon Carbon Co., Ltd. Agent Patent attorney Tatsuo Ito Agent Patent attorney Tetsuya Ito

Claims (1)

[Claims] 1. Divinylbenzene, polystyrene, polymerization catalyst, and dispersion medium are mixed as starting materials and heated at 60 to 80°C.
After separating the spherical product from the resulting dispersion, the residual polystyrene portion was removed with a solvent to obtain a porous spherical polymer, which was heated under an oxidizing atmosphere at a heating rate of 5.
Raise the temperature at ~50°C/hr and maintain it at 250-380°C,
Then, in an inert atmosphere or under vacuum, the temperature is increased at a rate of 50-40
A method for producing a carbonaceous adsorbent, which comprises raising the temperature at a rate of 0°C/hr and firing at a final treatment temperature of 500°C or higher. 2. The method for producing a carbonaceous adsorbent according to claim 1, wherein at least one of styrene, ethylvinylbenzene, or a toluene-soluble portion of pitch is added to the starting material.