Glycerol [propane-1,2,3-triol, glycerin(e)], a trihydric alcohol, is a clear, water-white, viscous, sweet-tasting hygroscopic liquid at ordinary room temperature above its melting point. Glycerol occurs naturally in combined form as glycerides in all animal and vegetable fats and oils, and is recove...
Glycerol [propane-1,2,3-triol, glycerin(e)], a trihydric alcohol, is a clear, water-white, viscous, sweet-tasting hygroscopic liquid at ordinary room temperature above its melting point. Glycerol occurs naturally in combined form as glycerides in all animal and vegetable fats and oils, and is recovered as a by-product when these oils are saponified in the process of manufacturing soap, when the oils or fats are split in the production of fatty acids, or when the oils or fats are esterified with methanol in the production of methyl esters(biodiesel). The growing production of biodiesel by transesterification of oil with alcohol is responsible for the surplus production of glycerol. Consequently, the price of glycerol has dropped dramatically and is expected to become a major platform material. The search for new applications of glycerol from which a broad spectrum of new valuable derivatives can be obtained is ongoing. Glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) is one of the glycerol derivatives which attracts attention for industrial applications. Glycerol carbonate is not flammable, water-soluble, readily biodegradable, nontoxic, and viscous liquid with a very low evaporation rate. Due to its properties, glycerol carbonate is widely used as protic solvent in resins and plastics, additives, wetting agent for cosmetics, carrier solvent for medical preparations, and chemical intermediate.
In this study, mixed oxide was prepared by the coprecipitation or the hydrothermal method under different conditions and used as catalyst for synthesis of glycerol carbonate by carbonylation of glycerol with urea. The physical properties of the prepared mixed oxide particles were investigated, as well as their activity as catalyst in the mentioned synthesis.
Mixed metal oxide particles were prepared by the coprecipitation using Zn and Al. The crystalline of ZnAl2O4 prepared Zn/Al mixed oxides was slowly increased with an increasing of the Al ratio. The Zn/Al mixed oxide prepared at Zn:Al=7:3 (molar ratio) showed the highest activity on the carbonylation of glycerol with urea ; the conversion of the glycerol was 82.7% and the yield of the glycerol carbonate 82.3%. The conversion of glycerol and the yield of glycerol carbonate can be obtained higher when active site ratio(=acid site density/base site density) is approx. 1. From this result, we may conclude that the acid and base site density and ratio of catalyaasts were very important parameters in the synthesis of glycerol carboante by carbonylation of glycerol with urea.
Zn/Al mixed oxide was prepared by the coprecipitation or the hydrothermal method under different conditions and used as catalyst for synthesis of glycerol carbonate by carbonylation of glycerol with urea. The physical properties of the prepared Zn/Al mixed oxdie particles were investigated, as well as their activity as catalyst in the mentioned synthesis. The Zn/Al mixed-oxide particles prepared by the coprecipitation method showed higher activity in synthesis of glycerol carbonate than those prepared by the hydrothermal method. The Zn/Al mixed oxide prepared by the coprecipitation method without NaNO3 showed the highest catalytic activity(82.4%) in synthesis of glycerol carbonate.
Glycerol [propane-1,2,3-triol, glycerin(e)], a trihydric alcohol, is a clear, water-white, viscous, sweet-tasting hygroscopic liquid at ordinary room temperature above its melting point. Glycerol occurs naturally in combined form as glycerides in all animal and vegetable fats and oils, and is recovered as a by-product when these oils are saponified in the process of manufacturing soap, when the oils or fats are split in the production of fatty acids, or when the oils or fats are esterified with methanol in the production of methyl esters(biodiesel). The growing production of biodiesel by transesterification of oil with alcohol is responsible for the surplus production of glycerol. Consequently, the price of glycerol has dropped dramatically and is expected to become a major platform material. The search for new applications of glycerol from which a broad spectrum of new valuable derivatives can be obtained is ongoing. Glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) is one of the glycerol derivatives which attracts attention for industrial applications. Glycerol carbonate is not flammable, water-soluble, readily biodegradable, nontoxic, and viscous liquid with a very low evaporation rate. Due to its properties, glycerol carbonate is widely used as protic solvent in resins and plastics, additives, wetting agent for cosmetics, carrier solvent for medical preparations, and chemical intermediate.
In this study, mixed oxide was prepared by the coprecipitation or the hydrothermal method under different conditions and used as catalyst for synthesis of glycerol carbonate by carbonylation of glycerol with urea. The physical properties of the prepared mixed oxide particles were investigated, as well as their activity as catalyst in the mentioned synthesis.
Mixed metal oxide particles were prepared by the coprecipitation using Zn and Al. The crystalline of ZnAl2O4 prepared Zn/Al mixed oxides was slowly increased with an increasing of the Al ratio. The Zn/Al mixed oxide prepared at Zn:Al=7:3 (molar ratio) showed the highest activity on the carbonylation of glycerol with urea ; the conversion of the glycerol was 82.7% and the yield of the glycerol carbonate 82.3%. The conversion of glycerol and the yield of glycerol carbonate can be obtained higher when active site ratio(=acid site density/base site density) is approx. 1. From this result, we may conclude that the acid and base site density and ratio of catalyaasts were very important parameters in the synthesis of glycerol carboante by carbonylation of glycerol with urea.
Zn/Al mixed oxide was prepared by the coprecipitation or the hydrothermal method under different conditions and used as catalyst for synthesis of glycerol carbonate by carbonylation of glycerol with urea. The physical properties of the prepared Zn/Al mixed oxdie particles were investigated, as well as their activity as catalyst in the mentioned synthesis. The Zn/Al mixed-oxide particles prepared by the coprecipitation method showed higher activity in synthesis of glycerol carbonate than those prepared by the hydrothermal method. The Zn/Al mixed oxide prepared by the coprecipitation method without NaNO3 showed the highest catalytic activity(82.4%) in synthesis of glycerol carbonate.
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