CS243528B1 - Process for the preparation of chelating derivatives of spherical cellulose with o, o'-dihydroxyazosm - Google Patents

Abstract

The solution relates to the field of sorbents for heavy metals. The aim of the solution is to prepare a sorbent for non-ferrous and precious metals with a high exchange capacity. According to the solution, this aim is achieved by a process in which spherical cellulose containing 2-methoxy-1-aminophenylsulfoethyl groups is treated with an aqueous solution of sodium nitrite in a dilute hydrochloric acid environment, after which the diazo-cellulose is washed with water and coupled with stirring. The cellulose derivative is then added to a solution of a mixture of sodium acetate, acetic acid and copper sulfate, and after cupration, decoupration is carried out with hydrochloric acid.

Description

(54) A process for the preparation of chelating spherical cellulose derivatives with o, o-dihydroxyazo group

The solution concerns the field of sorbents for heavy metals. The aim of the solution is to prepare a sorbent for non-ferrous and precious metals with high exchange capacity.

This object is achieved by treating spherical cellulose containing 2-methoxy-1-aminophenylsulfoethyl groups with an aqueous solution of sodium nitrite in a dilute hydrochloric acid medium, followed by coupling after washing the cellulose with water while stirring. The cellulose derivative is then added to a solution of a mixture of sodium acetate, acetic acid and cupric sulphate and, after coupling, decryption is carried out with hydrochloric acid.

The invention relates to a process for the preparation of spherical cellulose chelating derivatives containing o, o '- dihydroxyazo groups.

Compounds containing o-O-dihydroxyazo or o-hydroxy-o-alkoxyazo groups in the molecule are characterized by the formation of stable chelates with heavy metal ions. Because of this property, they are used in analytical chemistry to separate or mask heavy metals.

Their use is in most cases limited to the extraction technique of separation, as these compounds have not until recently been bound to a solid support. However, the separation of metal ions by extraction cannot be used in those cases where the metal ion in the solution is at a concentration of 0.2 ppb / 250 ml solution or even lower.

Under these conditions, the only possibility is to concentrate the metal ion from the solution with selective sorbents, as shown by the concentration factor, which is 1000 for ion exchange chromatography, while for extraction only 75.

The first mention of the binding of compounds with a .alpha.-dihydroxyazo group to a solid carrier (cellulose) is described in German Patent No. 2,629,542, whose disadvantage is, in particular, the low capacity of the prepared sorbents, which ranges from 0.3 to 1.0 mmol metal. / g cellulose.

According to the aforementioned German patent, the preparation of cellulose derivatives containing an o, o-dihydroxyazo group must be based on cellulose containing an o-aminophenol group. Cellulose containing the o-aminophenol group is prepared by heating a mixture of 10 g of cellulose, 21.2 g of 4 - [- beta-sulfatoethylsulfonyl] -2-aminophenol and 6 g of NaOH in 70 ml of dimethyl sulfoxide with 2 ml of water for 15 hours at 75 Deň: 32 ° C.

After acidification of the mixture and washing of the reaction liquid, diazotization and coupling are carried out by known methods. The preparation of this cellulose derivative is economically demanding, since the synthesis of 2-aminophenol-4- (beta-sulfatoxyethylsulfone), which is the starting material, is multistage and proceeds with low yields.

A certain lack of sorbents prepared according to the above-mentioned patent can be seen in the fact that the base matrix is not in a spherical form, resulting in an increase in the pressure drop of the sorbent column and the consequent deterioration of the liquid medium flow through the sorbent layer.

Said disadvantages of the chelating cellulose derivatives with o, o ** - dihydroxyazo group can be overcome by the process of the present invention.

The process for preparing spherical cellulose chelating derivatives according to the invention consists in diazotizing a 2-methoxy-1-aminophenylsulfoethyl group of the formula I

wherein R is hydrogen or methoxy, an aqueous solution of sodium nitrite in dilute hydrochloric acid and the subsequent coupling of the diacellulose according to the invention by adding the resulting cellulose derivative to a solution of sodium acetate, acetic acid and cupric sulphate and The 90 ° C was stirred for up to 16 hours, after which the cellulose was aspirated and washed with dilute hydrochloric acid and finally water to neutralize the filtrate.

Default modified spherical cellulose containing 2-methoxy-l-aminofenylsulfoetylové groups is prepared by alkylation of spherical cellulose 2-methoxy-l-aminophenyl / betasulfatoxyetylsulfonem / him of formula ₃ with a - _{CH2 CH2} - where X is as defined above in alkaline environment.

The diazotization of the spherical cellulose is carried out by known procedures with sodium nitrite in dilute hydrochloric acid at 0 to 20 ° C.

Separation of the cellulose is carried out by filtering off the reaction mixture and washing the cellulose with water.

Coupling agents used are those which contain a hydroxyl group in the molecule to which they are coupled to the ortho position. Preference is given to using p-cresol, resorcinol, N- (2,6-dihydroxybenzene) iminodioacetic acid, 1-naphthol-4-sulfonic acid, 2-naphthol-6-sulfonic acid, 2-naphthol-4-sulfonic acid, -naphthol-3,6-disulfonic acid, 2-naphthol-6,8-disulfonic acid, 1,8-aminonaphthol-4-sulfonic acid, 2,5-aminonaphthol-7-sulfonic acid, 2,8-aminonaphthol-6 -sulfonic acid, 1,8-aminonaphthol-3,6-disulfonic acid, 1,8-aminonaphthal-4,6-disulfonic acid, 1,8-aminonaphthal-2,4-disulfonic acid, 1,8-dihydroxynaphthalene-3 , 6-disulfonic acid. Coupling is carried out according to known methods.To convert the methoxy group, located ortho to the azo group, to the hydroxy group, by demethoxylation coupling, in a sodium ootane and acetic acid environment by known methods.

The advantage of the preparation process according to the invention is above all the achievement of higher exchange capacities of the prepared sorbents. A further advantage is the more versatile use of the starting spherical cellulose derivative containing 2-methoxy-1-aminophenylsulfoethyl groups by diazotizing and coupling with the passive components of the present invention, it is possible to prepare an ion exchange with o-methoxy-o-hydroxyazo groups which is also however, with a different order of selectivity of metal sorption compared to ion exchangers. containing o, o'-dihydroxyazo groups.

The use of hydrophilic and highly porous spherical cellulose as a carrier for o, o'-dihydroxyazo groups results in a large acceleration of metal sorption and easy accessibility of all active groups.

Spherical cellulose chelating derivatives containing o, o'-dihydroxyazo groups are used as sorbents for trapping or separating heavy metals.

Example 1

Diazotation of cellulose

20.3 g of aspirated spherical cellulose containing 2.434 mmol of bound [beta-sulfatoxyethyl] sulfonyl] -p-cresidine / g cellulose are diazotized with stirring with 10.8 ml of 2.5 M sodium nitrite in a medium of 27.0 ml of 2.5 M hydrochloric acid at 15 ° C for 30 minutes.

After the diazotization is complete, the diazocellulose is aspirated and washed with 5 x 50 ml of water.

Resorcinin coupling ‘The aspirated and washed diacellulose is added to a solution of resorcin prepared by dissolving 3.1 g of resorcin in a solution of 8.3 g of crystalline sodium acetate and 1.7 ml of glacial acetic acid in 45 ml of water. The mixture was stirred at 10 ° C for 8 hours. The cellulose derivative is then washed with water until the filtrate is colorless.

Demethoxydation kuprace

AND

243528 4

The washed and aspirated cellulose derivative is added with stirring to a solution containing 23.0 g of crystalline sodium acetate, 5.0 ml of glacial acetic acid and 8.3 g of copper crystalline sulfate. The mixture was stirred at 80 ° C for 15 hours. After cooling the reaction mixture, the cellulose derivative is suction filtered, washed with 5 x 50 ml of water, 5 x 50 ml of 15% hydrochloric acid and finally with water until the filtrate is neutral.

The cellulose thus prepared, containing a 4- (2,4-dihydroxyphenylazo) -2-methyl-5-hydroxyphenylethylsulfone group, has a capacity for me <3 71.7 mg Cu / g product, i.e. 1.12 mmol Cu per 1 g dry product.

Example 2

Diazotation of cellulose

23.3 g of aspirated spherical cellulose containing 2.506 mmol of 3-amino-4-methoxyphenyl-beta-sulfatoxyethylsulfone / g cellulose are diazotized with stirring as described in Example 1.

Coupling with 2-naphthol-6-sulfonic acid

The washed and aspirated diacellulose is added to a solution of 13.1 g of 48.2% 2-naphthol-6-sulfonic acid dissolved in a mixture of 50 ml of pyridine and 100 ml of water. After stirring at 10 ° C for 12 hours, the cellulose derivative is suction filtered and washed with water until the filtrate is colorless.

Demethoxydation kuprace

This was carried out analogously to Example 1.

The prepared spherical cellulose containing a 3/2-hydroxy-6-sulfonaphthyllazo / -4-hydroxyphenylethylsulfone group has a sorption capacity of 92.26 mg Cu / g product, i.e. 1.452 mmol Cu per g dry product.

Example 3

Diazotation of cellulose

26.4 g of aspirated spherical cellulose containing 2,300 mmol of bound 4-sulfatoxyethylsulfonyl-2,5-dimethoxyaniline / g cellulose are diazotized with stirring according to Example 1.

Coupling with 1,8-dihydroxynaphthalene-3,6-disulfonic acid

The washed and aspirated diacellulose is stirred in a solution containing 14.0 g of 72% 1,8-dihydroxynaphthalene-3,6-disulfonic acid and 1.5 g of sodium carbonate anhydrous in 50 ml of water at 10 ° C for 24 hours. hours. The cellulose derivative is suction filtered and washed with water until the filtrate flows colorless.

Demethoxydation kuprace

Oved, it is carried out in the same manner as in Example 1.

Cellulose containing 4- (1,8-dihydroxy-3,6-disulfo-2-naphthylazo) -2-methoxy-5-hydroxyphenylethylsulfone group has a sorption capacity of 96.58 mg Cu / g product, i.e. 1.520 mmol Cu / g dry product.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of spherical cellulose chelating derivatives with an o'-dihydroxyazo group by diazotizing a 2-methoxy-1-aminophenylsulfoethyl group of spherical cellulose wherein X is an aqueous solution of sodium nitrite in a dilute hydrochloric acid medium followed by coupling of diazocellulose; with stirring to a solution of a mixture of sodium acetate, acetic acid and copper sulfate and stirred at 70 to 90 ° C for 3 to 16 hours, then suctioned off and washed with dilute hydrochloric acid.