JPH10279919A - Production of metal-scavenging agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain a high performance metal-scavenging agent useful for treating waste fluids, waste smokes, etc., at a low cost without requiring a high pressure and the readdition of hydrochloric acid by polycondensing a polyalkylene polyamine with an alkylene dichloride and subsequently introducing specific functional groups to the polycondensation product. SOLUTION: This method for producing a metal-scavenging agent comprises polycondensing (A) a polyalkylene polyamine with (B) an alkylene dichloride in the presence of (C) water at the atmospheric pressure at a temperature of e.g. 30-120 deg.C and subsequently reacting the polycondensation product with (D) an aldehyde compound and (E) a phosphite salt at a temperature of e.g. 30-150 deg.C at the atmospheric pressure or a higher pressure to introduce functional groups such as alkylene phosphate (salt) groups to the polymer. The polycondensation reaction is preferably carried out in the presence of 5-60 wt.% of the component C in the reaction system. For the reaction for introducing the functional groups, the components D and E are used in amounts of 0.1-1.0 equivalent and 0.1-1.0 equivalent, respectively, per equivalent of the active hydrogen of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a metal collecting agent.

[0002]

2. Description of the Related Art Polyalkylene polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine and polyethyleneimines are reacted with aldehydes and phosphorous acids to form alkylene. A method for obtaining a metal collecting agent having a phosphate group or a salt thereof as a functional group is known.

[0003] The polyalkylene polyamine used in the above method for producing a metal collecting agent is conventionally produced by reacting ammonia with ethylene dichloride. This reaction must be performed under a high pressure of 10 atm or more. In addition, since a manufacturing apparatus capable of withstanding high pressure is required, a large capital investment is required. For this reason, ethylenediamine, which is in high demand, is provided at a relatively low cost. For example, polyalkylenepolyamines having a higher molecular weight than ethylenediamine, such as diethylenetriamine, tetraethylenepentamine, and pentaethylenehexamine, are twice or more than ethylenediamine. Sold at the price of

Polyethyleneimine is produced by a method of polymerizing cyclic ethyleneimine. Since ethyleneimine is a compound having a low boiling point and high toxicity, special equipment is required for producing polyethyleneimine. Ethyleneimine is not easily available. For this reason, polyethyleneimine is 10 times less than ethylenediamine and the like.
It is sold twice as expensive.

By the way, as a raw material for producing a metal collecting agent, a polyalkylene polyamine having a higher molecular weight than a low molecular weight polyalkylene polyamine such as ethylenediamine or polyethyleneimine having a molecular weight of about 300 or more is useful. However, as described above, since such a compound is more expensive than ethylenediamine, there is a problem that the product cost of the metal collector is high. Also,
Polyalkylene polyamines and polyethylene imines having a higher molecular weight than those conventionally marketed are practically difficult to obtain, and even if they are available, they become extremely expensive, and as a raw material for producing metal trapping agents. Not suitable.

[0006] Furthermore, when a metal collector manufacturer attempts to produce polyalkylene polyamine or polyethyleneimine necessary for the production of its own product by itself, a large capital investment is required, and raw materials are mass-produced. Unless you consume
There is a problem that the product cost of the metal collecting agent, which is the final product, becomes extremely high. Therefore, the metal trapping agent manufacturer must purchase and use the raw material polyalkylene polyamine from the polyamine manufacturer, but the polyalkylene polyamine and polyethylene which can be obtained from the polyamine manufacturer at low cost as the raw material for producing the metal trapping agent. There are relatively few types of imines, which has been a constraint in further improving the performance of the metal collector.

The present invention has been made to solve the above-mentioned problems, and has as its object to provide a method for producing a metal collecting agent which can provide a metal collecting agent having excellent performance at low cost.

[0008]

That is, the method of the present invention for producing a metal collecting agent comprises a step of polycondensing a polyalkylene polyamine and an alkylene dichloride at normal pressure in the presence of water.
It is characterized by introducing a functional group by reacting an aldehyde and a phosphorous acid.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyalkylene polyamine used in the present invention includes, for example, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tribubutylene. Examples thereof include tetramine, tetraethylenepentamine, tetrapropylenepentamine, tetrabutylenepentamine, pentaethylenehexamine, iminobispropylamine, monomethylaminopropylamine, and methyliminobispropylamine. Of these, inexpensive ethylenediamine and diethylenetriamine are preferred.

The above polyalkylene polyamine further comprises N
-A substituent having a hydroxyalkyl group, an acyl group, an alkyl group or the like may be used, but it is necessary that two or more primary amino groups or secondary amino groups remain in one molecule. The N-hydroxyalkyl substituent can be introduced by reacting the polyalkylene polyamine with an epoxy alkane; the N-acyl substituent is introduced by reacting the polyalkylene polyamine with a fatty acid; The alkyl substituent is introduced by reacting the polyalkylene polyamine with an alkyl halide; The N-hydroxyalkyl substituent preferably has 2 to 28 carbon atoms in the alkyl group.
The acyl substituent preferably has 2 to 24 carbon atoms.
The N-alkyl substituent preferably has 2 to 28 carbon atoms.

Examples of the alkylene dichloride to be subjected to the polycondensation reaction with the polyalkylene polyamine include ethylene dichloride, propylene dichloride, butylene dichloride and the like. As the polyalkylene polyamine and the alkylene dichloride, those having an alkylene group having the same carbon number may be reacted, or those having an alkylene group having a different carbon number may be reacted. When a polyalkylene polyamine having an alkylene group having a different number of carbon atoms is reacted with an alkylene dichloride, a metal collector based on a polyalkyleneamine having a structure in which different types of alkylene groups are bonded via an amino group is obtained.

In the method of the present invention, the polyalkylene polyamine and the alkylene dichloride can be reacted under normal pressure, but the reaction requires the presence of water. The reaction molar ratio between the polyalkylene polyamine and the alkylene dichloride is preferably from 1: 0.5 to 1.5. By adjusting the reaction ratio between the polyalkylene polyamine and the alkylene dichloride, it is possible to obtain a polyethyleneimine having the same structure as that obtained by polymerizing a cyclic ethyleneimine. In the method of the present invention, water is 5-6.
It is preferred that the compound is present in the reaction system at a ratio of 0% by weight.
If the amount of water is less than 5% by weight, stirring during the reaction becomes difficult,
On the other hand, if it exceeds 60% by weight, the reaction rate will decrease and the yield will deteriorate.

The polyalkylene polyamine and the alkylene dichloride are reacted by, for example, mixing the polyalkylene polyamine in a container equipped with a stirrer, dropping the alkylene dichloride under heating and stirring, and after completion of the dropping, further heating and maintaining the mixture under stirring. . The temperature at which the alkylene dichloride is dropped is preferably from 10 to 150 ° C., and the alkylene dichloride is preferably dropped over 1 to 10 hours. The temperature for heating and holding after completion of the alkylene dichloride dripping is about 30 to 120 ° C., and the holding time is about 1 to 10 hours.

After the completion of the above reaction, an aldehyde and a phosphorous acid are added and reacted. In the case of the conventional method in which a commercially available polyalkylene polyamine is used as a raw material and an aldehyde is reacted with phosphorous acid, a neutralization reaction between phosphorous acid and the amine occurs, thereby preventing the introduction of an alkylene phosphate group. In order to prevent this, it is necessary to add hydrochloric acid to react the polyalkylene polyamine with hydrochloric acid to form a hydrochloride. On the other hand, in the method of the present invention, the product formed by the reaction between the polyalkylene polyamine and the alkylene dichloride is obtained by adding hydrochloric acid to a polyalkylene polyamine (a polyalkylene polyamine having a higher molecular weight than the starting material polyalkylene polyamine). Since it has the same structure as that of the reaction, it is not necessary to add hydrochloric acid again when the aldehyde is reacted with phosphorous acid.

The aldehydes include acetaldehyde, formaldehyde, trioxane, paraformaldehyde and the like. Examples of the phosphites include phosphites such as phosphorous acid, methyl phosphite, and ethyl phosphite. Aldehydes and phosphorous acids are added in a ratio of 0.1 to 1.1 equivalents of aldehydes and 0.1 to 1.0 equivalents of phosphorous acid to 1 equivalent of active hydrogen of polyalkylene polyamine as a starting material. Preferably, the reaction is carried out. Aldehydes and phosphorous acids have a temperature of 30 to 1
The reaction is preferably carried out at 50 ° C. for 1 to 20 hours under normal pressure or under pressure. When phosphorous acid is used as the phosphorous acid, a metal scavenger having an alkylene phosphate group as a functional group is obtained. If the metal scavenger is treated with an alkali, a metal scavenger having a salt of the alkylene phosphate group as a functional group is obtained. A mass is obtained.

In the method of the present invention, a commercially available polyalkylene polyamine as a starting material can be used. In the method of the present invention, a polyalkylene polyamine as exemplified above can be arbitrarily selected and used as a starting material, but when a low molecular weight material which is commercially available at a low cost such as ethylenediamine is used as a starting material, It is preferable because the intended object of the present invention can be sufficiently achieved.

The metal collecting agent produced by the method of the present invention can collect gaseous metals contained in flue gas, incinerate ash and fly ash from garbage incineration plants, in addition to collecting metals in wastewater. In solid waste containing metals such as ash, slag discharged from mines, sludge as industrial waste generated by neutralization coagulation sedimentation treatment in wastewater treatment and sedimentation treatment with a coagulant, and highly contaminated soil. Can be used for the purpose of immobilizing a metal.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Examples 1 to 7 The amounts of polyalkylene polyamine and water shown in Table 1 were charged into a 1-liter four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a condenser, and the mixture was stirred under stirring at the dropping conditions shown in Table 1. The temperature was increased to the temperature shown in the section, and the alkylene dichloride in the amount shown in Table 1 was added dropwise from the dropping funnel over the time shown in the section of the dropping conditions at the same temperature. After completion of the dropwise addition, the polycondensation reaction was carried out while maintaining the reaction conditions shown in Table 1 while stirring the reaction system. Then, aldehydes shown in Table 1 in a flask,
Phosphorous acid was added and reacted at 85 to 95 ° C. for 8 hours. Table 2 shows the average molecular weight (measured by the GPC method) and the introduction rate of the functional group (the substitution rate of the functional group with respect to the amount of the original active hydrogen that can be substituted) of the metal collector thus obtained.

[0019]

[Table 1]

[0020]

[Table 2]

Reference Example 1 According to the method of Example 1, 150 g of an aqueous ammonia solution (28%) was charged instead of the polyalkylene polyamine.
After 278 g of ethylene dichloride was added dropwise at room temperature over 3 hours, the mixture was heated to 95 to 100 ° C. and stirred for 10 hours. Almost all ammonia and ethylene dichloride were recovered, and the consumption of ammonia was 0.5 g. The yield of polyamines based on the amount of ammonia was 1.2%.

[0022]

As described above, according to the method of the present invention, the polyamines obtained by reacting ammonia and alkylene dichloride under high pressure have a higher molecular weight than the conventional method in which a polyamine is used as a starting material for a metal collecting agent. Even metal collectors based on polyalkylene polyamines can be easily and inexpensively manufactured.

Also, polyalkylene polyamines having a higher molecular weight than commercially available polyalkylene polyamines have heretofore been difficult to obtain because of their high cost, but according to the method of the present invention, they are difficult to obtain conventionally. Can be easily and inexpensively manufactured even with a metal collector having a structure based on a high molecular weight polyalkylene polyamine. As a result, it is possible to easily provide a metal trapping agent having a structure that could not be actually manufactured conventionally.
For this reason, the structural range of the metal collecting agent is widened, and the performance of the metal collecting agent can be easily improved in terms of structure.

Furthermore, since the method of the present invention does not require a high-pressure reaction, a metal-catching agent manufacturer starts by producing a polyalkylenepolyamine as a raw material of a metal-catching agent, and then introduces a functional group into this polyamine to carry out metal-catching. The process up to the collection can be performed continuously. In addition, when a metal collector is produced using a commercially available polyalkylene polyamine as a raw material, hydrochloric acid once separated and removed (hydrochloric acid bound to the polyalkylene polyamine is added to an alkali in a polyalkylene polyamine production process). Need to be added again to the polyalkylenepolyamine, and then the aldehydes and the phosphorous acid need to be added and reacted. In the method of the present invention, the aldehydes and the phosphorous acid are added. When reacting with acids, it is not necessary to add hydrochloric acid again. For this reason, in the conventional method, a two-step process of purchasing a polyalkylene polyamine produced by a polyamine manufacturer and introducing a functional group into the polyalkylene polyamine to produce a metal catcher by the metal scavenger manufacturer is performed. Although it was necessary, and the unnecessary work of performing the reaction after adding the removed hydrochloric acid again was necessary, in the method of the present invention, only one step was required, and it was not necessary to add hydrochloric acid again. Since there is no such effect, there are various effects such as an increase in work efficiency, a reduction in work cost, and a reduction in production cost, in addition to an advantage that a high-pressure reaction is not required during the reaction step.

Claims (1)

[Claims] 1. After polycondensation of a polyalkylene polyamine and an alkylene dichloride at normal pressure in the presence of water,
A method for producing a metal collecting agent, comprising reacting an aldehyde and a phosphorous acid to introduce a functional group.