Basic chromium sulfates

Modem chrome-tanning methods are weU controUed and employ an extensive knowledge of the chemistry of the system. The most common chromium-tanning material used is basic chromium sulfate [12336-95-7] Cr(0H)S04, made by the reduction of sodium bichromate with sulfur dioxide or by sulfuric acid and a sugar. 

Leather Taiming. Oxahc acid is used as a pH modifier in leather tanning by tannin and basic chromium sulfate. It also functions as a bleaching agent for leather (qv). 

The most popular tanning solution in current use is termed 33% basic chromium(III) sulfate and corresponds to the empirical formula CrOHSCV In older procedures, chromate was often reduced at the plant using glucose/sulfuric acid mixtures. At present, 33% basic chromium sulfate is provided as either a solution (chrome liquor) or as a commercially available powder,120 of constant, but at present slightly uncertain, chemical composition. 

Cardiovascular Effects. Information regarding cardiovascular effects in humans after inhalation exposure to chromium and its compounds is limited. In a survey of a facility engaged in chromate production in Italy, where exposure concentrations were 0.01 mg chromium(VI)/m3, electrocardiograms were recorded for 22 of the 65 workers who worked in the production of dichromate and chromium trioxide for at least 1 year. No abnormalities were found (Sassi 1956). An extensive survey to determine the health status of chromate workers in seven U.S. chromate production plants found no association between heart disease or effects on blood pressure and exposure to chromates. Various manufacturing processes in the plants resulted in exposure of workers to chromite ore (mean time-weighted concentration of 0-0.89 mg chromium(ni)/m3) water-soluble chromium(VI) compounds (0.005-0.17 mg chromium(VI)/m3) and acid-soluble/water-insoluble chromium compounds (including basic chromium sulfate), which may or may not entirely represent trivalent chromium (0-0.47 mg chromium/m3) (PHS 1953). No excess deaths were observed from cardiovascular diseases and ischemic heart disease in a cohort of 4,227 stainless steel production workers from 1968 to 1984 when compared to expected deaths based on national rates and matched for age, sex, and calender time (Moulin et al. 1993). No measurements of exposure were provided. In a cohort of 3,408 individuals who had worked in 4 facilities that produced chromium compounds from chromite ore in northern New Jersey sometime between 1937 and 1971, where the exposure durations of workers ranged from <1 to >20 years, and no increases in atherosclerotic heart disease were evident (Rosenman and Stanbury 1996). The proportionate mortality ratios for white and black men were 97 (confidence limits 88-107) and 90 (confidence limits 72-111), respectively. 

Basic chromium(lll) salts with non-stoichiometric compositions are used in tanning, particularly oligomers of basic chromium(III) sulfate with the approximate composition Cr(OH)S04. Basic chromium sulfates are marketed as liquids or as a spray-dried powder. 

Basic chromium sulfates can be manufactured in different ways ... 

Manufacture of basic chromium sulfates from solutions obtained in the dichrorinate oxidation of organic materials such as montan waxes or anthracene... 

In each case basic chromium sulfates are formed together with sodium sulfate, which is desirable in that it acts as a buffer during the tanning process. 

Basic chromium sulfate utilized for the tanning of leather. 

Basic chromic sulfate Basic chromium sulfate. See Chromium sulfate, basic Basic cobalt chromate. See Cobalt chromate (ous)... 

Synonyms Basic chromic sulfate Basic chromium sulfate Chromic sulfate, basic Chromium hydroxide sulfate Chromium sulfate... 

R. Usha, T. Ramasami, Effect of crosslinking agents (basic chromium sulfate and formaldehyde) on the thermal and thermomechanical stability of rat tail tendon collagen fibre, Thermochimica Acta 356 (1-2) (2000) 59-66. 

Basochrome (basic chromium sulfate) Loader Contact pemphigus (Tsankov et al. 1990) ... 

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