Indian Journal of Chemistry Vol. 34A, April 1995, pp. 317-319 Synthesis, ion-exchange properties and analytical applications of a novel tin(IV)- sulphosalicylate exchanger Syed Ashfaq Nabi*, Nafisur Rahman. Wajahat U Farooqui & Soofia Usmani Analytical Chemistry Division, Department of Chemistry, Aligarh Muslim University, Aligarh 202 002 Received 30 September 1993; revised 21 December 1993; accepted 12 September 1994 Tin(IV)-sulphosalicylate has been synthesized by mixing aqueous solutions of tin(IV)-chloride and sulphosalicylic acid under different conditions. The most stable sample is prepared by refluxing for 16 hr. tin(IV) chloride (0.05 M) with sulphosalicylic acid (0.05 M) in the volume ratio of I: I. The thermal and chemical stabilities and the ion exchange capacity of this material have been studied. Inorganic ion-exchangers have received wide attention in the recent past. They have been reported to be superior to ion-exchange resins due to their enhanced thermal stability and selectivity'. Most of the known inorganic exchangers are based on metal hydroxides or metal phosphate, arsenate, vanadate, etc. Only a few attempts have been made to develop new materials based on the interaction of metal ions with organic compounds such as ethylenediamine- tetra acetic acid and trimethyl phosphonoacetate+'. Detailed studies have not been made on these due to their low chemical and thermal stabili ty. The present note deals with the preparation, properties and applications of tin(IV) sulphosalicylate as. a new inorganic exchanger. Experimental Stannic chloride pentahydrate (Polish Reagents POCh, Poland) and sulphosalicylic acid (SSA) (E Merck) were used as such. All other chemicals were of AR grade. TherqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA pH was measured with an Elico Li-I 0 pH meter. A BauschzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA & Lomb Spectronic 20 colorimeter and a Perkin Elmer 137 spectro- photometer were used for visible and IR studies respectively. A temperature controlled shaker (SICO) was used for shaking. Sn(lV) sulphosalicylate (SS), Sn(IV) phosphate (SP) and Sn(IV) sulphosalicylophosphate (SSP) were prepared by mixing aqueous solutions of the appropriate reagents under the conditions indicated in Table 1. The precipitate formed was allowed to stand for 24 h at room temperature. It was then filtered, washed with distilled water and dried at 40°C. The precipitate was immersed in I M HN0 3 for 24 h to convert it to the H+ form. The excess acid was removed by repeated washing with demineralised water. To determine its ion-exchange capacity, 0.5 g of the sample in H+ form was taken in a column with glass wool support. Solutions (I M) of different uni- and bi-valent cations were passed through the column and the H+ ion liberated was determined titrimetrically. The pH titrations were conducted for LiCI-LiOH, NaCI-NaOH and KCI-KOH systems at 25 ±2°C. The exchanger (sample SS20.5 g) was equilibrated with the desired soltuion at room temperature (25 ± 2°C) for 24 h with occasional shaking. Tin and sulpha salicylate released in the solution were determined photometrically using hematoxylin and ferric nitrate" as chromogenic reagents, respectively. The sample (SS20.2 g) w: dissolved in cone. HC\. The mole ratio of Sn(IV) and sulphosalicylic acid was found to be 1.0:2.1 IR spectrum ofSn(IV)- sulphosalicylate in H + form was recorded by KBr disc method. To examine the effect of drying temperature on the ion-exchange capacity, the material was heated at different temperatures in a muffle furnace for 1 h. Thermogravimetric analysis of sample SS2in H + form was performed at a heating rate of lOoC/min. The exchanger (0.5 g) in H + form was equilibrated with the cation solution (the total loading of cation was less than 3% of the total ion-exchange capacity of the material) for 6 h in a shaker incubator. The amount of cation before and after equilibration was determined by titrating agamst standard EDT A solution. ThevutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK Kd values were calculated as reported in literature:'. Separation of metal ions was carried out on a glass column (i.d., 0.6 em) using 2.0 g of the exchanger in H + form (mesh size 150-200).The flow rate of the effluent was maintained at I ml min - I throughout the elution process. Results and discussion Table 1shows that the mixing ratio of the reactants affects the physical appearance of the exchanger. On refluxing the precipitate for several hours, the chemical stability and ion exchange capacity were significantly increased. OptimumptJ was found to be