Study On The Synthesis Of Stearate For Heat Stabilizer

Stearate are very valuable compounds for heat stabilizer. In this paper, the synthesis of calcium stearate, magnesium stearate, zinc stearate and barium stearate are studied as emphasis. The synthesis of the four stearates were studied with hydrogen peroxide as the catalyst. The catalyst amount, reaction time, temperature, the ratio of material and other factors influencing the quality of stearate were particularly evaluated.The synthesis of calcium stearate was catalyzed by H₂O₂ with stearic acid and Ca(OH)₂ as materials,C2H5OH and NaOH as additive respectively. When NaOH was chosen as additive, the result of reaction was best. The compound in the form of the white powder was been obtained. The free acid mass fraction of calcium stearate was 0.3%, calcium content was 6.9%, heating loss was 0.3%, mp:149¹55℃.The synthesis of magnesium stearate was catalyzed by H₂O₂ with stearic acid and Mg(OH)2 or MgO as materials. The catalyst amount, reaction time, temperature, NaOH as additive and other factors influencing the free acid content of magnesium stearate were particularly evaluated.The optimal result of reaction was as follows: The free acid mass fraction was 0.4%, magnesium content was 4.5%, heating loss was 0.5%, mp:115¹21℃.The synthesis of zinc stearate was catalyzed by H₂O₂ with stearic acid and ZnO as materials. The catalyst amount, reaction time, temperature, NaOH as additive and other factors influencing the reaction were particularly evaluated. The optimized reaction conditions of zinc stearate were as follows: 50ml 30% H₂O₂,reaction temperature 120℃, reaction time 60min. The free acid mass fraction of zinc stearate was 0.4%, zinc content was 10.9%, heating loss was 0.5%, mp:121¹25℃.The optimized reaction conditions of barium stearate were as follows: stearic acid 150g and barium hydroxide 88g were heated melted at 110℃, 30ml 30% H₂O₂ and 50ml H2O were added together into the above mixture at 150℃and stirred for 35min, then 2%NaOH 100ml were added and stirred for 35min, thermal dehydration. The compound in the form of the white powder was obtained . The free acid content of barium stearate was 0.4%, barium content was 20.2%, heating loss was 0.2%, mp:207²13℃.