Multiphase catalysts and the reactants they catalyze are in different states. For example, in the production of margarine, solid nickel (catalyst) enables the conversion of unsaturated vegetable oil and hydrogen into saturated fat. Solid nickel is a multiphase catalyst and the reactants catalyzed by it are in liquid (vegetable oil) and gaseous (hydrogen) states.
Introduction to the varieties of silicone oil paint additives
Fluorocarbon surfactants are surfactants in which all or part of the oxygen atoms in the hydrophobic groups of the corresponding hydrocarbon surfactants are replaced by fluorine atoms. Compared with hydrocarbon surfactants, it has unique “three highs” (high surface activity, high heat stability and high chemical stability) and “two hydrophobic” (hydrophobic, oil-repellent) characteristics. These characteristics are determined by the unique structure of the fluorocarbon chain in the fluorocarbon surfactant.
Because the van der Waals attraction between the fluorocarbon chain is much lower than the corresponding hydrocarbon chain, it has a strong effect on both water and organic solution media. Very strong surface activity]. For example, a small amount of fluorocarbon surfactant can reduce the surface tension of water to 15mN/m and the surface tension of benzene and toluene to l1mN/m. The critical micelle concentration (CMC) of the solution is very low, reaching 10 -5~10-6mol/L, so that its dosage is greatly reduced, wax emulsion for ceramics and sometimes even only 10 mg/kg can produce high surface activity. Since the atomic radius of fluorine is larger than that of hydrogen atoms (rp=1.35×1010m, rH=1.20×10-10m), compared with hydrocarbon chains, in fluorocarbon chain molecules, fluorine atoms are more tightly enclosed in the carbon-carbon chain. Surrounding, coupled with the carbon-fluorine bond bond energy is much higher than the carbon-hydrogen bond bond energy (C-F bond 485kJ/mol, CH bond 416kJ/mol), so that the fluorocarbon surfactant has high heat resistance stability And high chemical stability.
Fluorocarbon surfactants are widely used in textiles, leather, papermaking, mineral processing, pesticides, chemicals, fire protection, coatings and other fields. It is mainly used in the petrochemical industry as a polymer material emulsifier, plastic rubber release agent, polymerization system dispersion stabilizer, agricultural shed film antifogging agent, chemical oil displacement agent, oil production foaming agent, fracturing acidification aid Agent, workover fluid, water plugging agent and crude oil demulsifier, etc. In the daily chemical industry, it is used as a compound to prepare high-end cosmetic emulsions and to formulate high-end cosmetics, especially fluoroalkyl mixed two-tail surfactants synthesized from perfluoroiodoane as a raw material. It belongs to the latest development for use in cosmetics. Fluorine-containing surfactants can be used to formulate a variety of cosmetics and emulsions.
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