Acrylic Acid Yield Research Articles

Vapor-phase reaction of methanol with methyl acetate and acetic acid in the presence of oxygen

Vapor-phase reactions of methanol with methyl acetate and acetic acid in the presence of gaseous oxygen were studied using a binary phosphate catalyst with a V/Ti/P atomic ratio of 1/2/5.2. In the presence of gaseous oxygen, methyl acetate itself undergoes hydrolysis to methanol and acetic acid, then the produced methanol is oxidized promptly to formaldehyde, and finally the formaldehyde reacts with acetic acid and methyl acetate. The yields of acrylic acid and methyl acrylate attained 21 and 13 mol%, respectively, at 330 °C with SV = ca. 310 h −1. In the presence of an excess of oxygen, the sum of the yields of acrylic acid and methyl acrylate was almost the same, whether one of the reactants was formaldehyde or methanol, and whether methanol was fed in with methyl acetate or acetic acid. It was found that the oxidation of methanol and the esterification-hydrolysis proceed much more promptly than the aldol condensations. In the reaction of methanol with acetic acid at 350 °C with a feed rate of CH 3COOH/CH 3OH/O 2/N 2 = 19/38/25/350 mmol/h (SV = ca. 340 h −1), the yields of acrylic acid and methyl acrylate attained 42 and 13 mol% (based on the charged acetic acid), respectively, and the selectivity of acetic acid to the condensation products was about 73 mol%.

Vapor-phase aldol condensation of formaldehyde with acetic acid on V 2O 5P 2O 5 catalysts

V 2O 5P 2O 5 binary oxides with P V atomic ratios from 1.06 to 1.2 were found to be effective as catalysts for the aldol-type condensation of formaldehyde (HCHO) with acetic acid to form acrylic acid. As the source of HCHO, 37% formalin or trioxane was employed. In the case of trioxane, the yield of acrylic acid attained about 98 mol%, based on the charged HCHO with the acetic acid/HCHO molar ratio of 2.5. On the other hand, in the case of formalin, the yield attained about 75 mol%, and methyl acetate and methyl acrylate were also formed by the esterification of the acids with methanol present in the formalin. The main side-reaction is the decomposition of acetic acid to form acetone and CO 2. This side-reaction is greatly accelerated over acrylic acid formation by an elevation of the temperature. The rates of both reactions were found to be inhibited by water vapor. The reactions of HCHO with derivatives of acetic acid, such as methyl acetate and acetaldehyde, were also Studied.

ChemInform Abstract: Oxidation of Propane to Acrylic Acid on V2O5‐P2O5‐Based Catalysts

Abstract V 2 O 5 P 2 O 5 -based oxides were found to be effective as catalysts for the partial oxidation of propane, using gaseous oxygen as an oxidant. Acrylic acid was the sole product other than carbon oxides. The best results for the formation of acrylic acid are obtained with this Te/P/V atomic ratio; 0.10−0.15/1.15/1 oxide catalysts. The yield of acrylic acid attains 10.5 mol%. As the extent of the reaction increases, the selectivity steadily decreases, while the yield first increases and then attains a maximum at a propane conversion of about 50%. The rate of reaction increases with an increase in the concentrations of both oxygen and propane, while it remains almost unchanged with the addition of water vapor to the feed gas. On the other hand, for the formation of acrylic acid, higher concentrations of oxygen and water vapor, a lower concentration of propane, and a lower reaction temperature are found to be favorable.

Partial oxidation of propylene on V 2O 5P 2O 5-based catalysts

The vapor-phase oxidation of propylene was studied over V 2O 5, V 2O 5P 2O 5, and V 2O 5P 2O 5TeO 2 catalysts in the presence of water vapor. On pure V 2O 5, the oxidation products were acetic acid and carbon oxides, plus a small amount of acetone. As the content of phosphorus added to V 2O 5 increases, the oxidation activity markedly decreases; on the other hand, the selectivity to acrylic acid increases and passes through a maximum at P V atomic ratio = 1.15 to 1.6, while that to acetic acid gradually decreases. With the V 2O 5P 2O 5 ( P V = 1.15 ) catalyst, the yield of acrylic acid attains 25 mol%, that of acetic acid is less than 10 mol%, and that of acrolein is less than 0.7 mol%. The effects of the third components added to V 2O 5P 2O 5 ( P V = 1.15 ) were also studied. It was found that TeO 2 is the sole additive which can improve the catalyst performance. As the amount of TeO 2 increases, the specific oxidation activity increases, as do the formation of acrolein and the sum of the yields of acrylic acid and acrolein, while the formation of acetic acid passes through a maximum at Te V = 0.02 to 0.04 . With the V 2O 5P 2O 5TeO 2 (Te/P/V = 0.15/1.15/1) catalyst, the yield of acrylic acid attains 38 mol% when air is used as the oxidant and 42 mol% when oxygen is so used. The effects of reaction variables, such as the oxygen concentration, the propylene concentration, the water vapor, and the temperature, on the activity and selectivity were also studied.

Oxidation of propane to acrylic acid on V 2O 5&P 2O 5-based catalysts

V 2O 5P 2O 5-based oxides were found to be effective as catalysts for the partial oxidation of propane, using gaseous oxygen as an oxidant. Acrylic acid was the sole product other than carbon oxides. The best results for the formation of acrylic acid are obtained with this Te/P/V atomic ratio; 0.10−0.15/1.15/1 oxide catalysts. The yield of acrylic acid attains 10.5 mol%. As the extent of the reaction increases, the selectivity steadily decreases, while the yield first increases and then attains a maximum at a propane conversion of about 50%. The rate of reaction increases with an increase in the concentrations of both oxygen and propane, while it remains almost unchanged with the addition of water vapor to the feed gas. On the other hand, for the formation of acrylic acid, higher concentrations of oxygen and water vapor, a lower concentration of propane, and a lower reaction temperature are found to be favorable.

Photophysical studies of a copolymer of acrylic acid and 1-pyreneacrylic acid adsorbed on calcium carbonate

The emission spectrum, polarisation of fluorescence measurement, and transient fluorescence decay characteristics of pyrene in an adsorbed copolymer of acrylic acid and 1-pyreneacrylic acid yield information on the location of the pyrene with respect to the surface; this is related to the configuration of the adsorbed as revealed by e.s.r. spectroscopy.

Preparation of Acrylic Acid

A modified Reppe process for manufacturing acrylic acid (AA) under normal pressure and another method by hydrolysis of acrylonitrile (AN) are reported. I. Modified Reppe process using normal pressure under continous operation.Thier reaction is affected by various factors such as molar ratio, acetylene feeding velocity, reaction temperature, circulation velocity, viz, agitating velocity and so on.The best reaction conditions were as follows : Acetylene feeding velocity : 200 l/hr.Reaction temperature : 40°CCirculation velocity for the reaction mixture : 1, 800 l/hr.Reaction composition : AA/Solvent=1/1 (wt.) Solvents : MEK, MIBKThe yield was about 80%.II. AN hydrolysisThe follwing reactions for conversion of AN into AA were studied.CH2=CHCN+H2SO4+H2O→CH2=CHCONH2·H2SO4CH2=CHCONH2·H2SO4 +H2O→CH2=CHCOOH + NH4HSO41. The first step reaction (formation of acrylamide).AN/sulfuric acid/water=1/1.5/4 (molar ratio) was employed at 12°C for 5 hrs with strring.The yield was about 95%.2. The second step reaction (formation of AA) The hydrolysis of acrylamide was effected by using 6 mol suplementary water per mol of acrylamide at 100°C for 2 hrs with stirring.Over-all yield of AA was about 850.3. KineticsThe apparent activation energy for the hydrolysis of AN was about 11.3 kcal/mol and the reaction was found to be second order in the concentrations of AN and water.