20858-25-7Relevant articles and documents
Efficient concrete foam stabilizer and preparation method thereof
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, (2021/07/17)
The invention discloses an efficient concrete foam stabilizer and a preparation method thereof, according to the efficient foam stabilizer, polyol is subjected to an esterification reaction to form ester bonds, and the ester bonds are connected with amphiphilic side chains, and the number of the amphiphilic side chains is 3-7; one end of the amphiphilic side chain is a hydrophobic chain segment, and the other end of the amphiphilic side chain is a hydrophilic unit; wherein the hydrophobic chain segment is an alkyl chain (R) with 8-14 carbons, and the hydrophilic unit is 2-10 ethylene oxide units. The efficient concrete foam stabilizer is a multi-chain type surfactant, and the multi-chain type surfactant is hydrolyzed under the alkaline condition to release an air-entraining type surfactant. The efficient concrete foam stabilizer has an excellent effect of stabilizing the air content of concrete, meanwhile, hardened concrete has a better pore structure, and the hardening strength of the concrete cannot be greatly influenced.
Chromium(VI) oxide oxidation of non-ethoxylated and ethoxylated alcohols for determination by electrospray ionization mass spectrometry
Beneito-Cambra, Miriam,Bernabe-Zafon, Virginia,Simo-Alfonso, Ernesto F.,Ramis-Ramos, Guillermo
experimental part, p. 2093 - 2100 (2011/11/06)
A new derivatization procedure to increase the sensitivity of electrospray ionization mass spectrometry (ESI-MS) to non-ethoxylated and ethoxylated alcohols was investigated. The analytes were oxidized with chromium(VI) oxide and the resulting carboxylic and ethoxy-carboxylic acids were isolated by extraction with ethyl acetate; the extracts were alkalinized and infused into the ESI-MS system working in the negative-ion mode. The yields of the combined oxidation-extraction were ca. 100% for non-ethoxylated fatty alcohols dissolved in acetone and they decreased moderately in samples containing increasing amounts of water (e.g., a 75% yield was obtained with 50% water). Ethoxylated alcohols with more than two ethylene oxide units resulted in yields of ca. 60%. Low limits of detection (LODs) were obtained when the procedure was applied to the analysis of body- care products and cosmetics containing fatty alcohols, e.g., in a varicose-vein cream, the LODs were 25 μ cetyl alcohol and 7.5 μ stearyl alcohol (detected as palmitic acid and stearic acid, respectively) per gram of sample. High molecular mass alcohols were also detected in seawater after pre- concentration by solid-phase extraction. Thus, the proposed method is particularly valuable for use in industrial samples having complex matrices and in environmental samples and it is competitive with other methods for the analysis of trace amounts of fatty alcohols.
