Patent GB-472624-A (GB)
Title: Improvements in or relating to preservatives, antiseptics, germicides and the like
IPC: A01N37/40
Filed: 1935-12-24
Abstract: The calcium salts of hydroxy - methyl - isopropyl-benzene-carboxylic acids, such as o-carracrotic acid, are prepared by heating a suspension in water of the acid and calcium carbonate, cooling and filtering the mixture, and crystallizing out the salt. Hydroxyquinoline-carboxylic acids or their esters or ethers are rendered water-soluble by admixture with acids or acid salts, such as citric, tartaric or lactic acids or potassium bisulphate, whereby salts or double salts are obtained.ALSO:Carboxylic groups may be introduced into essential oils by treatment of the oils or their solutions at elevated temperature with metallic sodium whilst passing carbon dioxide, or by treatment of the oils with potassium permanganate.  Hydroxyl groups may be introduced by treating the oils with caustic soda and formaldehyde.  The products are used as germicides.ALSO:Antiseptics, preservatives and fungicides, for the treatment of foods, medicines, adhesives, oils, tannin extracts, inks, sizes and other substances, comprise one or more of the following compounds, viz. hydroxy benzene carboxylic acids containing at least two alkyl groups as nuclear substituents or in which the benzene nucleus is fused with a further iso- or hetero-cyclic ring; salts, esters or ethers of these acids; halogen derivatives of the foregoing compounds; substances produced by subjecting essential oils or their constituents to chemical treatment whereby carboxyl or hydroxyl groups or both are introduced.  The salts used may be those of alkali or alkaline earth metals or magnesium or the active compounds may be used in conjunction with water-soluble alkaline earth or magnesium salts of inorganic or organic acids.  In the case of hydroxy quinoline carboxylic acids, these may be used in aqueous solution in admixture with citric, tartaric or lactic acid or potassium bisulphate.  The preservatives may be used in solid or liquid form or as solutions, colloidal solutions, or emulsions made with fatty alcohol sulphonates or other emulsifying agents, and they may be incorporated with the substances to be treated, or applied externally thereto, or dispersed in the atmosphere in which the substances are stored.  Solutions are preferably used at pH 7 or less and the acidity may be adjusted to obtain selective action against particular micro-organisms.  Active substances definitely specified include the following, viz.-thymotic, carvacrotic, 8-hydroxy-quinoline-7-carboxylic, b -naphthol-a -o-carboxylic, and dimethyl-hydroxy-benzene carboxylic acids, the methyl, propyl and isobutyl esters and sodium, calcium and magnesium salts of some of these, and the hydroxylated and carboxylated derivatives of various specified essential oils.  Carboxyl groups may be introduced into essential oils by treatment of the oils or their solutions at elevated temperature with metallic sodium whilst passing carbon dioxide, or by treatment of the oils with potassium permanganate. Hydroxyl groups may be introduced by treating the oils with caustic soda and formaldehyde.  The calcium salts of hydroxy - methyl-isopropyl-benzene carboxylic acids, such as o-carvacrotic acid, are prepared by heating a suspension in water of the acid and calcium carbonate, cooling and filtering the mixture, and crystallizing out the salt.  Hydroxy-quinoline carboxylic acids or their esters or ethers are rendered water-soluble by admixture with acids or acid salts, such as citric, tartaric or lactic acids or potassium bisulphate whereby salts or double salts are obtained.