JP4931043B2 - Modification method of cross-linked organic polymer - Google Patents

Description

  The present invention relates to a method for modifying a crosslinked organic polymer having a quaternary ammonium group. Specifically, the crosslinked organic polymer having a quaternary ammonium group is brought into contact with an aqueous medium at a temperature lower than the critical temperature and lower than the critical pressure, thereby reducing the quaternary ammonium group to a free molecular weight. Further, the present invention relates to a method for modifying a crosslinked organic polymer, wherein the crosslinked organic polymer is separated from the crosslinked organic polymer.

  A crosslinked organic polymer having a quaternary ammonium group has been used for a wide range of applications as a strongly basic anion exchanger, but is chemically stable and a method for reusing substances has not been established. As a treatment method after use of this crosslinked organic polymer, a solidification method, an incineration method, a landfill method, and the like are known, but among these, the solidification method and the landfill method are not desirable in terms of recycling and recycling of substances, The incineration method consumes a large amount of heat energy, and there are concerns about the generation of nitrogen oxides and environmental pollutants.

In addition, a method of decomposing by treating with an oxidizing agent in water at a temperature or pressure higher than the critical point (Japanese Patent Publication No. 1-38532), or a method of producing an oily product by treating in supercritical water in a non-oxidizing atmosphere. (Japanese Patent Laid-Open No. 11-49889) has also been proposed, but is not satisfactory from the viewpoint of energy saving and resource circulation, such as requiring a large amount of energy for a special pressure-resistant reactor or heating and pressurization. There wasn't.
Japanese Patent Publication No. 1-38532 JP 11-49889 A

  As described above, the material reuse of the crosslinked organic polymer having a quaternary ammonium group is difficult to realize by a known method.

  The present invention has been made to solve such a problem. The object of the present invention is to modify the crosslinked organic polymer under a relaxed condition to separate and recover a functional group component while reducing energy consumption, and to form a substrate. Another object of the present invention is to provide a method for modifying a crosslinked organic polymer that can be reused together with the crosslinked organic polymer.

As a result of intensive studies, the present inventors have made the fourth organic compound having a quaternary ammonium group contact with an aqueous medium at a temperature lower than the critical temperature and a pressure lower than the critical pressure. It has been found that the secondary ammonium polymer can be separated and recovered from the crosslinked organic polymer by efficiently reducing the molecular weight of the secondary ammonium as a nitrogen compound and releasing the nitrogen compound to the aqueous medium side.
This invention is made | formed based on such knowledge, and makes the following a summary.

(1) has a cross-linked polystyrene backbone, and a cross-linked organic polymer having a quaternary ammonium group, 200 ° C. or higher 370 ° C. or less, in an atmosphere of less than及beauty 1 MPa or more 22 MPa, by contacting with water medium A method for modifying a crosslinked organic polymer, characterized in that the quaternary ammonium group is reduced in free molecular weight and separated from the crosslinked organic polymer.
(2) The method for modifying a crosslinked organic polymer according to claim 1, wherein the aqueous medium is pure water or an aqueous salt solution.
( 3 ) The method for modifying a crosslinked organic polymer according to (1) or (2) , wherein the crosslinked organic polymer having a quaternary ammonium group is a strongly basic anion exchange resin.
( 4 ) The method for modifying a crosslinked organic polymer according to any one of (1) to (3), wherein the quaternary ammonium group is a trialkylammonium group and / or a dialkylalkanolammonium group.
(5) crosslinked organic whole quaternary ammonium group has Tsunemasa charge in the polymer or a portion thereof, is neutralized with one or more mineral ions that characterized that (1) to ( 4) The method for modifying a crosslinked organic polymer according to any one of the above.
( 6 ) The method for modifying a crosslinked organic polymer according to ( 5 ), wherein the mineral acid ion is a chloride ion.
(7) The method for modifying a crosslinked organic polymer according to any one of (1) to (6), wherein the crosslinked polystyrene skeleton is polystyrene crosslinked with divinylbenzene.

  According to the present invention, a crosslinked organic polymer having a quaternary ammonium group can be efficiently transformed without undergoing high energy treatment such as supercritical water. As a result, the nitrogen compound that has been reduced in molecular weight from the quaternary ammonium group to the aqueous medium side can be rendered harmless and assimilated by a method such as microbial decomposition, and the crosslinked organic compound from which the quaternary ammonium group portion has been removed. The polymer skeleton can be further modified, recovered, and reused as a fuel or a monomer for various synthetic raw materials.

Hereinafter, embodiments of the method for modifying a crosslinked organic polymer of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications may be made within the scope of the gist thereof. Can be implemented.
In the following, “(meth) acryl” refers to both “acryl” and “methacryl”.

[1] Crosslinked organic polymer The crosslinked organic polymer according to the present invention must have a quaternary ammonium group. Hereinafter, the crosslinked organic polymer according to the present invention will be described.

[1-1] Cross-linked organic polymer The cross-linked organic polymer according to the present invention is a solid or a solid having an arbitrary shape that is granulated or appropriately cut or pulverized, and various chemical structures of the substrate are applicable. is there.

  Examples of the chemical structure of the substrate-crosslinked organic polymer include synthetic polymers such as crosslinked polystyrene, poly (meth) acrylic acid, and crosslinked poly (meth) acrylate, and crosslinked polysaccharides produced in nature such as cellulose. Is mentioned. Among these, synthetic polymers are preferable, and crosslinked polystyrene is more preferable.

  As the cross-linked polystyrene, polystyrene cross-linked with divinylbenzene is preferable. The blending amount of polystyrene divinylbenzene crosslinked with divinylbenzene is usually 2% by weight or more, preferably 3% by weight or more, and usually 10% by weight or less, preferably 8% by weight or less based on polystyrene.

  The cross-linked organic polymer according to the present invention is not particularly limited in shape, form, size, etc., such as granular, fibrous, membrane, etc., but, for example, adsorbing materials, and intermediate materials for processing such as ion exchangers and chelating agents The particle size is usually 5 mm or less, preferably 1 mm or less, and usually 0.1 mm or more, preferably 0.2 mm or more.

[1-2] Quaternary ammonium group The quaternary ammonium group of the crosslinked organic polymer according to the present invention is centered on one nitrogen atom, and (i) contains at least one carbon atom and is shared by the nitrogen atom. 3 organic chains that are bonded but not covalently bonded to the polymer substrate (crosslinked organic polymer as the substrate), and (ii) one covalently bonded to the nitrogen atom at one end and covalently bonded to the polymer substrate at the other end It is a functional group having an ordinary positive charge composed of the organic chain.

  Examples of the organic chain that is not covalently bonded to the polymer substrate of (i) include a linear or branched alkyl group that may be independently substituted. Here, examples of the substituent which may be substituted include a hydroxyl group and a mercapto group. The straight chain or branched alkyl group usually has 1 or more carbon atoms and usually 4 or less.

  Examples of the organic chain covalently bonded to the nitrogen atom at one end and covalently bonded to the polymer substrate at the other end of (ii) include an optionally substituted alkylene group, phenylene group, and polyoxyalkylene group. Here, examples of the substituent which may be substituted include a hydroxyl group and a mercapto group. Further, the alkylene group usually has 1 or more carbon atoms and usually 4 or less. The polyoxyalkylene group usually has 2 or more carbon atoms and usually 6 or less.

  Examples of such a quaternary ammonium group include a trialkylammonium group and a dialkylalkanol ammonium group, and a trimethylammonium group, a triethylammonium group, and a dimethylethanolammonium group are preferable.

  The amount of the quaternary ammonium group contained in the crosslinked organic polymer is not particularly limited, but the quaternary ammonium group for the crosslinked organic polymer of the substrate is usually 0.5 meq / g or more, preferably 1 meq / g. g to 10 meq / g, preferably 5 meq / g.

  The quaternary ammonium group is a functional group having a normal positive charge, but the whole or a part thereof is electrostatically neutralized by a negative charge such as one or more mineral acid ions. The negative charge in this case includes mineral acid ions such as chloride ion, bromide ion, sulfate ion, and the like, and among them, chloride ions are used from the practical point of view and the point of rapidly completing the decomposition reaction. Product ions are preferred.

[1-3] Modification Mode of Crosslinked Organic Polymer By carrying out the method for modifying a crosslinked organic polymer of the present invention, a quaternary ammonium group in the crosslinked organic polymer is free and low molecular weight and separated from the crosslinked organic polymer. Is done. Thereby, a quaternary ammonium group containing a substance such as a nitrogen-containing functional group or halogen is removed, and the crosslinked organic polymer of the substrate can be used as a material circulation or energy source.
In the present invention, “modification” means controlling the chemical reactivity of a substituent without changing the main skeleton as a substrate of the crosslinked organic polymer.

[2] Method for modifying cross-linked organic polymer The present invention provides the cross-linked organic polymer in the above [1] section by contacting with an aqueous medium at a temperature lower than the critical temperature and a pressure lower than the critical pressure. A quaternary ammonium group is made free and low molecular and separated from the crosslinked organic polymer.

[2-1] Modification Condition In the present invention, it is essential to bring the crosslinked organic polymer into contact with the aqueous medium at a temperature lower than the critical temperature and a pressure lower than the critical pressure. Here, the critical temperature in the present invention refers to a point where there is no distinction between gas and liquid in gas-liquid equilibrium. For example, the critical temperature of pure water is 374 ° C. In the case of pure water, the critical pressure is 22 MPa (220 atm).

  The modification of the crosslinked organic polymer of the present invention is performed under an atmosphere lower than the critical temperature, and the atmospheric temperature is 200 ° C. or higher, preferably 230 ° C. or higher, more preferably 250 ° C. or higher, and 370 ° C. or lower. is there. If the ambient temperature is too high, too much energy is consumed and the durability of the apparatus is lowered. If the ambient temperature is too low, the reaction time becomes long or sufficient reaction is not performed.

  Moreover, the atmospheric pressure in the case of implementing at the said critical temperature is 0.1 Mpa or more, Preferably it is 1 Mpa or more, More preferably, it is 5 Mpa or more, Less than 22 Mpa, Preferably it is 21 Mpa or less, More preferably, it is 20 Mpa or less. If the atmospheric pressure is too high, too much energy is consumed and the durability of the apparatus is lowered. If the atmospheric pressure is too low, the reaction time becomes long or sufficient reaction is not performed.

  In addition to water vapor, a stable gas substrate material such as nitrogen may be present in the atmosphere, but this is not essential.

  As a method of bringing the crosslinked organic polymer having a quaternary ammonium group into contact with an aqueous medium, there is usually mentioned a method of immersing the crosslinked organic polymer in an aqueous medium in the above atmosphere, and specifically, [2 -3].

  Further, although the modification proceeds in a short time, the modification result can be controlled by setting a treatment time corresponding to a desired modification rate (desired quaternary ammonium group decomposition / removal rate). The treatment time is usually 3 minutes or longer, preferably 5 minutes or longer, usually 300 minutes or shorter, preferably 120 minutes or shorter. The treatment time is appropriately set according to the decomposability and chemical properties of the target crosslinked organic polymer.

[2-2] Aqueous medium for modification treatment As an aqueous medium used in the modification method of the present invention, pure water or an aqueous salt solution is used.

  Moreover, when using salt aqueous solution as a water medium, sodium chloride, potassium chloride, calcium chloride etc. are mentioned as the salts.

  Further, the aqueous medium used in the modification method of the present invention is a surfactant or the like for the purpose of promoting mass transfer of water molecules inside a crosslinked organic polymer having a quaternary ammonium group that is a solid. It may contain an amphiphile. In this case, the content of the amphiphilic substance is usually 0% by weight or more and usually 1% by weight or less.

  The amount of the aqueous medium used in the modification method of the present invention is usually 50% by weight or more, preferably 100% by weight or more, and usually 1000% by weight based on the weight of the crosslinked organic polymer having a quaternary ammonium group. % Or less, preferably 500% by weight or less. If the amount of the aqueous medium used is too small, the reaction may be incomplete. If the amount is too large, the amount of the aqueous medium and the energy utilization efficiency are lowered, which is uneconomical.

[2-3] Aspect of modification method The modification treatment according to the present invention can be performed by either a batch method or a distribution method, and a known apparatus can be used as it is or in combination. That is, in a sealed pressure-resistant container, a prescribed amount of a crosslinked organic polymer having a quaternary ammonium group and a water medium are placed, heated to a predetermined temperature and then held at a predetermined pressure to complete the treatment, or A method is adopted in which the aqueous medium is fed in by a pump or the like from one of the cylindrical reaction tubes filled with the crosslinked organic polymer having a quaternary ammonium group, and the modified mixture is discharged from the other.

[3] Treatment after modification Due to the modification of the crosslinked organic polymer according to the present invention, the quaternary ammonium group portion of the crosslinked organic polymer is free-degraded and dissolved in the aqueous medium.
This treated aqueous medium is usually treated by microbial decomposition or the like.
On the other hand, the cross-linked organic polymer from which the quaternary ammonium group portion has been separated by modification is simplified in chemical composition by removing the quaternary ammonium group portion, and is further modified as necessary to provide a fuel source. It can be reused as a monomer for various synthetic raw materials.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

Example 1
A commercially available strong basic anion exchange resin “Diaion PA308 (chloride form; content of divinylbenzene relative to polystyrene) which is a crosslinked organic polymer having a quaternary ammonium group in a stainless steel tube having an inner diameter of 8 mm and a length of 150 mm. 4 wt% styrene - divinylbenzene crosslinked copolymer) "manufactured by (Mitsubishi Chemical Corporation) was added to 0.4g of pure water 2.5g was sealed at both ends, 330 ° C., and held at 20 M Pa 30 minutes .

  After cooling, the solid layer was collected and subjected to elemental analysis. As a result, nitrogen was not detected, and it was confirmed that all quaternary ammonium groups were removed from the ion-exchange resin substrate.

Example 2
The same operation as in Example 1 was performed except that “Diaion SAT10 (hydroxide type)” (manufactured by Mitsubishi Chemical Corporation) was used as the ion exchange resin. The nitrogen content of the recovered solid phase was At 1.7% by weight, about 75% of the quaternary ammonium groups were liberated, but did not result in complete decomposition.

Claims (7)

It has a cross-linked polystyrene backbone, and a cross-linked organic polymer having a quaternary ammonium group, 200 ° C. or higher 370 ° C. or less, in an atmosphere of less than及beauty 1 MPa or more 22 MPa, by contacting with water medium, the second A method for modifying a crosslinked organic polymer, characterized in that a quaternary ammonium group is reduced to a low molecular weight and separated from the crosslinked organic polymer. The method for modifying a crosslinked organic polymer according to claim 1, wherein the aqueous medium is pure water or an aqueous salt solution. The method for modifying a crosslinked organic polymer according to claim 1 or 2 , wherein the crosslinked organic polymer having a quaternary ammonium group is a strongly basic anion exchange resin. The method for modifying a crosslinked organic polymer according to any one of claims 1 to 3, wherein the quaternary ammonium group is a trialkylammonium group and / or a dialkylalkanol ammonium group. All or part of the quaternary ammonium group has Tsunemasa charges in crosslinked organic polymer, any one of claims 1 to 4, characterized in that it is neutralized with 1 or more mineral acid ion 2. A method for modifying a crosslinked organic polymer according to item 1. 6. The method for modifying a crosslinked organic polymer according to claim 5 , wherein the mineral acid ion is a chloride ion. The method for modifying a crosslinked organic polymer according to any one of claims 1 to 6, wherein the crosslinked polystyrene skeleton is polystyrene crosslinked with divinylbenzene.