GB271236A - Improved process for stabilising hydrocyanic acid - Google Patents

Abstract

271,236. Deutsche Goldund Silber- Scheideanstalt vorm. Roessler, and Kerschbaum, F. May 5, 1926. Fumigants. - In the stabilization of hydrocyanic acid bv admixture with an absorbent such as diatomite, infusorial earth, kieselguhr, &c., the latter before use is freed from objectionable basic substances such as calcium sulphide, carbonate or oxide by pretreatment with an acid such as sulphuric or hydrochloric acid, an acid salt such as sodium bisulphate or an acid derivative, such as an ester of chloracetic acid, ethyl sulphuryl chloride, or the methyl ester of chlorocarbonic acid. Certain of the esters have a stabilizing effect on the hydrocyanic acid or are irritants and serve as warning substances. The absorbent may be treated when in the natural state or after roasting, and an excess of acid over that theoretically needed may be used, or any excess may be washed out. Instead of, or in addition to, being subjected to the acid treatment, the absorbent may be so treated as to contain a large amount of oxygen, as by blowing air through the heated absorbent during roasting. The treated absorbent may be allowed to absorb the maximum quantity of hydrocyanic acid, or larger amounts of the acid may bs mixed with the absorbent. Irritant and warning substances, e.g. chlor-picrin or cyanogen chloride, may be added to the acid or to the mixture of acid and absorbent. Specifications 230,346 and 232,834, [Class 1 (ii), Inorganic compounds, other than &c.], are referred to.