Formation of Methyl Acrylate from Methyl Acetate and Formaldehyde Condensation over Solid Base Catalysts

Abstract

The vapor-phase aldol condensation of methyl acetate (MeOAC) with formaldehyde (HCHO) to form methyl acrylate was investigated over solid base catalysts. A variety of solid base catalysts were prepared by loading Cs2O over SiO2 or Al2O3 as the support materials. The properties of the solid base catalysts were characterized by XRD, BET and CO2-TPD. The results of the vapor-phase aldol condensation indicated that SiO2 and Al2O3 modified with Cs2O showed high conversation of methyl acetate and high selectivity of methyl acrylate. 22.6% conversation of methyl acetate and 16.5% yield of acrylic acid and methyl acrylate were obtained over Cs-Al2O3. In addition, Cs-SiO2 exhibited about 42% selectivity to methyl acetate. The high yield of acrylic acid and methyl acrylate is attributed to the high base property of catalysts.

Synthesis of acrylic acid through aldol condensation of acetic acid with formaldehyde catalyzed by Bi‐,W‐ and Cs‐doped B2O3/SiO2 nanocomposites

“…At high reaction temperature, two formaldehyde molecules could react to form one methanol molecule and one formic acid molecule. 8,9 Methanol can react with acetic and acrylic acids to form methyl acetate and methyl acrylate on the acid active sites. Formic acid can be decomposed to CO 2 and H 2 .…”

“…Considering the wide application of methyl acrylate, the synthesis of methyl acrylate through the one‐step aldol condensation reaction between methyl acetate and formaldehyde also has been investigated by several research groups. When the aldol condensation reaction between methyl acetate and formaldehyde (formalin, 36 wt% formaldehyde) with a methyl acetate/formaldehyde molar ratio of 6:1 was carried out on caesium monoxide (Cs 2 O)/alumina (Al 2 O 3 ) and Cs 2 O/SiO 2 catalysts at 380 °C, the total yields of both methyl acrylate and acrylic acid were 13.4% and 15.5% at the methyl acetate conversions of 19.1% and 14.6% (respectively) 8 . When the aldol condensation reaction between methyl acetate and formaldehyde (trioxymethylene) with a molar ratio of 0.5:1 was conducted on the Cs 2 O/SBA‐15 catalyst at 390 °C, the methyl acrylate selectivity reached 95% at the methyl acetate conversion of 48.4% 9 .…”

“…When the aldol condensation reaction between methyl acetate and formaldehyde (formalin, 36 wt% formaldehyde) with a methyl acetate/ formaldehyde molar ratio of 6:1 was carried out on caesium monoxide (Cs 2 O)/alumina (Al 2 O 3 ) and Cs 2 O/SiO 2 catalysts at 380 °C, the total yields of both methyl acrylate and acrylic acid were 13.4% and 15.5% at the methyl acetate conversions of 19.1% and 14.6% (respectively). 8 When the aldol condensation reaction between methyl acetate and formaldehyde (trioxymethylene) with a molar ratio of 0.5:1 was conducted on the Cs 2 O/SBA-15 catalyst at 390 °C, the methyl acrylate selectivity reached 95% at the methyl acetate conversion of 48.4%. 9 The alkali sites could effectively catalyze the aldol condensation reaction to the formation of acrylic acid and methyl acrylate.…”

Cesium Loaded on an Al-Modified Silica Support Catalyst for Methyl Acrylate Synthesis by Aldol Condensation of Methyl Acetate and Formaldehyde

“…20 Wang et al reported the synthesis of MA by the aldol condensation of Ma and FA over the silica-and aluminasupported Cs 2 O catalyst; the optimal selectivity (41.96%) and yield (6.26%) to MA could be obtained using silica as the support. 21 In recent years, the supported acid−base bifunctional catalyst performed well in the aldol condensation due to the easy-to-control acid−base sites. 26 They studied that Cs and P were implicated in the regulation of the acidity of the alumina oxide support.…”

“…Owing to the easy preparation method, many researchers studied the effect of solid base catalysts such as alkali metal oxide or alkaline earth metal oxide on the aldol condensation of Ma and FA. , Mamoru et al also prepared some supported solid alkali and alkali earth metal hydroxide catalysts; they found that cesium hydroxide was the best base active component and silica was the sole support effective for the reaction . Wang et al reported the synthesis of MA by the aldol condensation of Ma and FA over the silica- and alumina-supported Cs 2 O catalyst; the optimal selectivity (41.96%) and yield (6.26%) to MA could be obtained using silica as the support . In recent years, the supported acid–base bifunctional catalyst performed well in the aldol condensation due to the easy-to-control acid–base sites. − Li et al prepared the Zr–Mg–Cs/SiO 2 bifunctional catalyst by coimpregnation and obtained 55.4% conversion of methyl propionate and 75.3% selectivity of methyl methacrylate .…”