SU819057A1 - Method of preparing rhodium-containing silicagel - Google Patents

Description

argon gas to prevent the oxidation of two-valeic tin. The impregnation was carried out for 24 hours with occasional shaking of the flask with the sample. At the end, the solid product is separated from the solution, washed with ethanol until Rh and Sn are absent in the washing liquid and extracted at room temperature under vacuum. The content of the main components in the resulting product is: Rh 0.003-0.46 weight. %, Sn 0.007-1.07 weight. % with an atomic ratio of Rh: Sn equal to 1: 2, and corresponds to that in the complex anion Rh (SnCl3) 2.

Example 1. South of large-pore silica gel SSC brand is loaded into the reactor, dried at 200 ° C to constant weight, and treated at the same temperature for 3 hours with vapors of titanium tetrachloride in a stream of dry nitrogen. Dry nitrogen is then blown through the bed at 200 ° C until complete removal of excess TiCU and the resulting HC1.

Freshly prepared sample is treated with an ethanol solution containing a complex anion. For this, 10 g of titanium-containing silica gel is placed in the flask. The sample is poured with a solution containing the complex anion (SnCl3) 2CU in ethanol (the solution is prepared as follows: 0.48 g of SnCb 2 H2O is dissolved in 25 ml of ethanol and poured with the same solution 0.3 g of RhCb-ЗНгО (Rh: Sn 1: 2). The mixture is heated for 30 minutes at 80 ° C, purging argon through it to prevent oxidation of divalent tin. The solution is then cooled to room temperature. The flask with the support and rhodium tinned ethanol is rinsed with argon and kept for 24 hours with occasional shaking. impregnated carrier is separated from uterine thief on a porous glass filter, washed with ethanol to the absence of rhodium and tin in solution and dried in vacuum at room temperature.The content of the main components in the product: Rh 0.46 wt.%, Sn 0.07 wt.%.

PRI mme R 2. Same as in example 1, but silica gel is pre-treated with TiCU vapors in a stream of dry air. The composition of the product: Rh 0.47 weight. %, Sn - 1.06 wt. %

Froze Same as in example 1, but the silica gel is not subjected to pre-treatment with vapors TiCl4, and dried at 2QO ° C. The content of Rh and Sn in the sample is less than 0.003 weight. %

PRI me R 4. Same as in example 1, but the processing pairs of TiCU are within 1.5 hours. The composition of the product: Rh 0.37 weight. %, Sn 0.72 wt. 7o

PRI me R 5. Same as in example 1, but the processing pairs of TiCU are carried out for

0.25 hours. Composition of the product: Rh 0.15 weight. %, Sn 0.33 wt. %

Thus, the results show that without pretreatment with TiCl4 vapors on the surface of silica gel, it is practically impossible to obtain a rhodium-free compound strongly bound to the surface.

According to the proposed method, it is possible to control the concentration of silica, which is firmly attached to the surface of silica gel, quite simply and in a wide range (0.003-0.46 wt.% In Rh and 0.007-1-1.07 wt.% In Sn).

5 The strength of the bond between the rhodium-containing groups and the surface of the rhodium-containing silica gel is also indicated by the data obtained from studying the effect of washing the silica gel after sorption on the change in the content of one of the elements of the sorbed compound (rhodium). It was established that the content of rhodium in the titanium-containing silica impregnated with a solution of the complex anion, but not washed with ethanol, is 4.0 wt. % The same product after washing with ethanol (200 ml) contains 0.46 wt. % RHODA (example I). Long-term exposure (120 h) of the product in ethanol does not lead to a decrease in

Keep it in it. The product also shows complete resistance to the action of other organic solvents: acetone, ether, benzene, dimethyl sulfoxide, dimethylacetamide.

5 In the case of using pure silica gel (Example 3), the content of rhodium in the impregnated but not washed silica gel is 0.16 weight. % After washing with ethanol (200 ml), the product contains less

0 0,003 weight. % give birth Moreover, when the product is kept in ethanol (48 h), a characteristic red color of the solvent (the color of the rhodium tin compound) is observed, which indicates desorption

5 Rhodi from the surface of the carrier into the solution.

The proposed method is important for on. students of heterogeneous catalysts with a predetermined optimal composition of the catalytically active component, the value

Which may vary widely for specific catalytic catalytic processes.

In addition, carrier activation also allows using it as a highly effective sorbent of complex compounds of platinum group metals from organic solutions.

Claims (2)

The invention of the method for producing a rhodium-containing silica gel, comprising impregnating the starting silica gel with a solution of an organic rhodium-containing compound, washing it and drying, characterized in that in order to increase the concentration of rhodium and increase the strength of its bond with the top 56 nostyo silica gel, before impregnation of sil-sources of information, Kage is treated with four ENT istrymprinnye into account during the examination titanium in a dry carrier gas, a1. US Patent No. 3968053, cl. 200-168, the impregnation is carried out with a solution of ethano-1976. la, containing complex ion Rhx 5 2. J. am. Chem. Soc., 1975, 97, No. 26, x {5nc1l) 2c14r-s. 7489 (prototype). 819057