Zinc soap
| Zinc salts of individual fatty acids |
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Zinc soap is a collective name for zinc salts of individual fatty acids or - more often - mixtures of zinc salts of several fatty acids.
Manufacturing
The saponification of natural fats and oils with alkali hydroxide or ammonia provides mixtures of the alkali or ammonium salts of fatty acids and glycerine . By precipitation with inorganic zinc salts, the corresponding zinc soaps are obtained from the alkali or ammonium salts of the fatty acids. The proportions of the individual fatty acid anions in the zinc soap mixture depends on the nature and provenance of the triglyceride used as the raw material . The direct production of zinc soap by reacting natural fats and oils with zinc oxide or zinc hydroxide is also possible. A chemically largely uniform zinc soap can be obtained by reacting a pure fatty acid with a stoichiometric amount of zinc oxide . Examples of such zinc soaps are:
- Zinc oleate, the zinc salt of oleic acid .
- Zinc palmitate, the zinc salt of palmitic acid (hexadecanoic acid).
- Zinc stearate, the zinc salt of stearic acid (octadecanoic acid), white, neutral, amorphous, fluffy, water-repellent powder, insoluble in water and alcohol (ethanol) and ether . Technical zinc stearate consists of about 65% zinc stearate, 25% zinc palmitate and 10% zinc soaps of other fatty acids.
use
Zinc soaps are used as a drying agent in paints and varnishes, as an agent for waterproofing fabrics, yarns, leather and porous rocks, thickeners in mineral oil- based lubricants and lubricants , as fire extinguishing powder, impregnation agents in the building materials and paper industry, in the rubber industry as an activator for Vulcanization accelerator , as a mastication aid and as a rubber powder agent and in the cosmetic and pharmaceutical industry for the production of powder, skin cream and ointment and as a stabilizer for PVC and in water-repellent preparations.
Zinc stearate is used to manufacture powder, cream and ointment in the cosmetic and pharmaceutical industries. According to the European Pharmacopoeia, zinc stearate may contain zinc oleate and zinc palmitate in "varying amounts" for use in pharmacy, so the composition of the fatty acid fraction is not clearly defined.
More soaps
Individual evidence
- ^ Brockhaus ABC chemistry. VEB FA Brockhaus Verlag Leipzig 1965, p. 870.
- ↑ a b Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 6: T-Z. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1988, ISBN 3-440-04516-1 , p. 4713.
- ↑ a b Brockhaus ABC chemistry. VEB FA Brockhaus Verlag Leipzig 1965, p. 871.
- ↑ European Pharmacopoeia. Deutscher Apotheker Verlag Stuttgart, 6th edition, 2008, ISBN 978-3-7692-3962-1 , pp. 4402-4403.