“Synthesis of a,b-unsaturated ketones over thermally activated Mg-Al hydrotalcites”

JUANA I. DI COSIMO; VERÓNICA K. DÍEZ; CARLOS R. APESTEGUÍA

APPLIED CLAY SCIENCE

Elsevier

Lugar: Amsterdam; Año: 1998 vol. 13 p. 433 - 449

0169-1317

The synthesis of a,b-unsaturated ketones on hydrotalcite-derived Mg–Al mixed oxides was studied. Five samples with Mg–Al ratios of 0.5–9.0 were prepared by coprecipitation and characterized by infrared spectroscopy, CO2 chemisorption and X-ray photoelectron spectroscopy. The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO studied. Five samples with Mg–Al ratios of 0.5–9.0 were prepared by coprecipitation and characterized by infrared spectroscopy, CO2 chemisorption and X-ray photoelectron spectroscopy. The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO a,b-unsaturated ketones on hydrotalcite-derived Mg–Al mixed oxides was studied. Five samples with Mg–Al ratios of 0.5–9.0 were prepared by coprecipitation and characterized by infrared spectroscopy, CO2 chemisorption and X-ray photoelectron spectroscopy. The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO 2 chemisorption and X-ray photoelectron spectroscopy. The selectivity to a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO a,b-unsaturated ketones wmesityl oxideMO., isomesityl oxideIMO., and isophoroneIP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO IP.x on pure MgO and calcined hydrotalcites was practically 100%. Magnesium oxide contained both the highest basic site density and the strongest basic sites; as a result, it exhibited a high activity for acetone oligomerization reactions. The addition of small amounts of Al to MgO MgrAl)5.diminished drastically the density of surface basic sites because of a significant Al surface enrichment, and caused the catalytic activity to drop. At higher Al content1-MgrAl-5. surface enrichment, and caused the catalytic activity to drop. At higher Al content1-MgrAl-5. MgrAl)5.diminished drastically the density of surface basic sites because of a significant Al surface enrichment, and caused the catalytic activity to drop. At higher Al content1-MgrAl-5.1-MgrAl-5. the incorporation of Alq3 cations within the MgO lattice increased the basic site density and the catalytic activity partially recovered. Al-rich HTC samplesMgrAl-1.converted acetone at a high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. catalytic activity partially recovered. Al-rich HTC samplesMgrAl-1.converted acetone at a high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. q3 cations within the MgO lattice increased the basic site density and the catalytic activity partially recovered. Al-rich HTC samplesMgrAl-1.converted acetone at a high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization. MgrAl-1.converted acetone at a high rate, probably reflecting an optimum concentration of acid–base sites for promoting both the acid and the base-catalyzed acetone condensations. Formation of IP increased with the Al content at expenses of mesityl oxides. It appears that the cyclization of linear trimers to yield IP is favored on samples with higher surface hydroxylation. Calcined Mg–Al hydrotalcites with high Al content are therefore suitable catalysts for producing IP from acetone oligomerization.