CS243556B1 - Chetlatation metal sorbents on base of spherical celullose and method of their preparation - Google Patents

Description

(54) Spherical cellulose chelating metal sorbents and process for their preparation

The present invention relates to spherical cellulose chelating metal sorbents and a process for their preparation.

Chelating sorbents find application not only in analytical chemistry for separation of various metals with similar chemical properties, but also in technical practice, eg in hydrometallurgy, in nuclear industry in separation and enrichment of radionuclides and in removal of toxic metals from waste water etc.

Most chelating sorbents have been prepared on the basis of polymeric carriers such as a copolymer of styrene and divinylbenzene. Some chelating polymeric sorbents are also commercially produced, such as CHELEX 100, LEWATIT TP 207, WOFATIT MC 50, DIAION CR 10, which contain the iminodiacetic acid residue as the basic chelating group.

All of these polymer-based sorbents have more or less hydrophobic properties; moreover, in a three-dimensional polymer, the polymer network makes some chelating groups unavailable to the diffusing ions or at least substantially retards their diffusion. For these reasons, ^one equilibration with chelating polymers based sorbents slow.

One of the few polysaccharide-based chelating sorbents commercially produced is the so-called CHELATING SEPHAROSE 6B (from Pharmacia Fine Chemicals AB, Sweden) containing also an iminodiacetic acid residue bound to cross-linked agarose. However, the chelating capacity of this sorbent is very low for common needs (30 μπιοίύ Zn / ml sorbent) and this sorhent is more suitable for use in affinity chromatography.

These deficiencies are eliminated by a spherical cellulose chelating sorbent with a macroporous structure of the general formula

-O-CH 2 CH 2 O * CH 2 SO 4

OH

2433 56 where

SR ............

n is 0 or 1,

X is a coupled compound capable of complexing with metals.

The essence of the process for the preparation of spherical cellulose chelating metal sorbents is to form a spherical cellulose or a hydroxyalkyl derivative thereof containing 4-aminophenyl-2-hydroxypropylsulfone groups of the general formula:

-O-ICH ^ O CH CH CH _{£ £} ^ oy with ^ά _m OH wherein n has the above meaning, firstly with stirring an aqueous solution of sodium nitrite in the environment of diluted hydrochloric acid at 0 to 10 ° C for 0, After 5 to 2 hours and after aspirating and washing the diacellulose with water, it is added to a stirred solution of the coupling compound cooled to 0 to 10 ° C and kept at the same temperature with stirring for 3 to 24 hours, after which the chelating sorbent is sucked off. The reaction liquids are washed with water, optionally first with a solvent dissolving the coupling compound and then with water.

The advantages of the chelating sorbents of the present invention reside in the enhancement of its capacity, the easy diffusion of metal ions to the functional groups, due to the macroporous cellulose skeleton.

The starting modified spherical cellulose containing 4-aminophenyl-2-hydroxypropylsulfone groups is prepared by alkylating the spherical cellulose or its hydroxyalkyl derivative with 4-acetaminophenyl- (3-chloro-2-hydroxypropyl) sulfone in an alkaline medium (Tokar O., Rydl J .: AO no. 245,807].

The diazotization of the spherical cellulose or its hydroxyalkyl derivative is carried out by known methods with sodium nitrite in a medium diluted with hydrochloric acid at a temperature of 0 to 10 ° C.

Coupling agents used are those coupling compounds which form complex compounds with metals. Preference is given to using 8-hydroxyquinoline, diphenylthiocarbazone, 4- (2-pyridylazo) resorcinol, salicylic acid, 1,8-dihydroxynaphthol-3,6-disulfonic acid, 1-amino-8-hydroxynaphthol-3,6-disulfonic acid, N- (2,6-dicarboxybenzene) iminodiacetic acid, 2- (di / carboxymethyl / aminoethyl) phenol, resorcin.

Example 1 g of aspirated spherical cellulose containing 0.885 mmol of 4-aminophenyl-2-hydroxypropylsulfonic acid groups / g cellulose is diazotized while stirring with 4.2 ml of 2.5 M sodium nitrite in an aqueous solution containing 10.6 ml of 2.5 M acid hydrochloric acid at 10 ° C for 30 minutes. After the diazotization is complete, the cellulose is suctioned off and washed with 5 X 50 ml of water.

Coupling with 8-hydroxyquinoline

The aspirated and washed diacellulose is added to a solution of 1.6 g of 8-hydroxyquinoline in 50 ml of ethyl alcohol. After stirring at 5 ° C for 16 hours, the cellulose derivative is suction filtered, washed with 5 X 50 ml of ethanol and finally with water until the effluent filtrate is colorless.

The prepared spherical cellulose contains 0.721 mmol of 4- (8‘-hydroxyquinolin-5‘-azoj-phenyl-2-hydroxypropylsulfone groups).

Example 2 g of spherical cellulose containing 0.885 mmol of 4-aminophenyl-2-hydroxypropylsulfone groups / g cellulose is diazotized with stirring as described in Example 1.

Coupling with salicylic acid

The aspirated and washed diacellulose is added to a solution of salicylic acid prepared by dissolving 1.5 g of salicylic acid and 1.16 g of sodium carbonate in 50 ml of water with stirring. The reaction mixture was stirred at 10 ° C for 24 hours. The sorbent is then suction filtered off the excess reaction liquid and washed with water until the filtrate is colorless.

The prepared spherical cellulose contains 0.650 mmol of 4- (3‘-carboxy-4‘-hydroxyphenylazo) -phenyl-2-hydroxypropylsulfone groups per gram of cellulose.

Example 3 g of aspirated spherical cellulose hydroxyethyl derivative containing 0.795 mmol of 4-aminophenyl-2-hydroxypropylsulfone groups per gram of cellulose is diazotized with 4.3 ml of a 2.5 M sodium nitrite solution * in the presence of 10.8 ml of 2.5 with stirring. M hydrochloric acid in 50 ml of water at room temperature

1.15 g of sodium carbonate. The mixture is stirred at 5 ° C for 24 hours, then the product is suction filtered from the reaction liquid and washed with water until the filtrate is colorless.

The prepared spherical cellulose contains 0.513 mmol of 4-λ, 8‘-dihydroxy-3 ‘, 6‘-disulfo-2‘ -naphthyl-phenyl-2-hydroxypropylsulfonyl groups / g cellulose.

Claims (2)

Subject 1. Chelating sorbent of spherical metals A cellulose of the formula wherein n is 0 or 1, X is a coupled compound capable of complexing with metals. 2. A process for the preparation of a spherical cellulose chelating metal sorbent according to claim 1, characterized in that the spherical cellulose or its hydroxyalkyl derivative containing 4-aminophenyl-2-hydroxypropylsulfone groups of the general formula: -O- (CH £ C / - / - O j - C / γ where ......... n is as defined above, first, with stirring, with an aqueous solution of sodium nitrite in a medium of dilute hydrochloric acid at 0 to 10 ° C for 0.5 to 2 hours and after aspirating and washing the diazocellulose with water, this is added to a stirred solution of the coupling compound cooled to 0-10 ° C and kept at the same temperature under stirring for 3 to 24 hours, after which the chelating sorbent is washed with water, optionally first with a solvent dissolving the coupling compound. then water.