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With hydrogen bromide; acetic anhydride; acetic acid; In titanium-clad;
EXAMPLE IV One hundred and sixty-six (166) g (0.933 mole) of p-acetoxyacetophenone, 100 g (0.98 mole) of acetic anhydride, 250 g (4.17 moles) of acetic acid, 1.2 g (0.0048 mole) of Co(OAc)2.4H2 O, 1.2 g (0.0049 mole) of Mn(OAc)2.4H2 O, and 1.6 g (0.01 mole) of 48% HBr were combined in a two-liter titanium-clad autoclave. The mixture was heated to 300 F. and pressurized to 300 psi. Air was introduced at a rate of 0.75 scf/min for the first fifteen minutes and then lowered to 0.63 scf/min for the remainder of the reaction. During the oxidation, a mixture of 140 g (1.37 moles) of acetic anhydride and 35 g (0.58 mole) of acetic acid was added through a pump. The oxidation ran for 31 minutes. The reaction solution was cooled and evaporated from 678 g to 579 g. The precipitated p-acetoxybenzoic acid was filtered and dried to yield 106 g with a purity of 96.4 mole % (61 mole % yield). Analysis of the filtrate showed: p-acetoxybenzoic acid, 18.2 mole %, p-acetoxyacetophenone, 2.4 mole %, p-hydroxybenzoic acid, 1.3 mole %. Analysis of the reactor wash showed p-acetoxybenzoic acid, 2.2 mole %. Total reaction yield of p-acetoxybenzoic acid was 81.4 mole %.
With hydrogen bromide; acetic anhydride; acetic acid; In titanium-clad;
EXAMPLE V One hundred and sixty-six (166) g (0.933 mole) of p-acetoxyacetophenone, 100 g (0.98 mole) of acetic anhydride, 250 g (4.17 moles) of acetic acid, 0.35 g (0.0014 mole) of Co(OAc)2.4H2 O, 0.35 g (0.0014 mole) of Mn(OAc)2.4H2 O, and 0.47 g (0.0028 mole) of 48% HBr were combined in a two-liter titanium-clad autoclave. The mixture was heated to 300 F. and pressurized to 300 psi. Air was introduced at a rate of 0.75 scf/min for 15 minutes and then lowered to 0.61 scf/min for the remainder of the reaction. During the run, a solution of 150 g (1.47 moles) of acetic anhydride and 38 g (0.63 mole) of acetic acid was added through a pump. The run time was 31 minutes. The reaction solution was concentrated by evaporating acetic acid from 696 g to 660 g. The precipitated p-acetoxybenzoic acid was isolated by filtration and dried to give 81.3 g of 97.6 mole % purity (47.2 mole % yield). Analysis of the filtrate showed: p-acetoxybenzoic acid, 32 mole %, p-hydroxybenzoic acid, 0.3 mole %, and p-acetoxyacetophenone, 3.2 mole %. Analysis of the reactor wash showed p-acetoxyacetophenone, 2.1 mole %. Total reaction yield of p-acetoxybenzoic acid was 81.3 mole %.
With hydrogen bromide; acetic anhydride; acetic acid; In titanium-clad;
EXAMPLE VI One hundred and sixty-six (166) g (0.933 mole) of p-acetoxyacetophenone, 100 g (0.98 mole) of acetic anhydride, 250 g (4.17 moles) of acetic acid, 3.5 g (0.0014 mole) of Co(OAc)2.4H2 O, 3.5 g (0.0014 mole) of Mn(OAc)2.4H2 O, and 4.7 g (0.0028 mole) of 48% HBr were combined in a two-liter titanium-clad autoclave. The reaction mixture was heated to 300 F. and pressurized to 300 psi. Air was introduced at a rate of 0.75 scf/min. During the run, a solution of 54 g (0.53 mole) of acetic anhydride and 13 g (0.217 mole) of acetic acid was added through a pump. The run time was 25 minutes. Analyses of the total reactor effluent and wash showed: p-acetoxybenzoic acid, 87 mole % yield, p-hydroxybenzoic acid, 1.2 mole % yield, and p-acetoxyacetophenone, 3.5 mole % yield.
EXAMPLE II The oxidation of p-acetoxyacetophenone proceeded as in Example I, except that the reaction was run for 30 minutes and a total of 150 g (1.47 moles) of acetic anhydride and 37 g (0.62 mole) of acetic acid was added through the pump. The reaction mixture was concentrated from 772 g to 413 g by evaporation of acetic acid. The slurry was filtered to remove precipitated p-acetoxybenzoic acid. After drying, 128.2 g of p-acetoxybenzoic acid of 95 mole % purity (73% yield) were obtained. Remaining in the filtrate were: p-acetoxybenzoic acid, 8.5 mole % yield, p-acetoxyacetophenone, 1.8 mole % yield, p-hydroxybenzoic acid, 0.6 mole % yield.
With hydrogen bromide; acetic anhydride; acetic acid;
EXAMPLE VII Seventeen and one-tenth (17.1) g (0.096 mole) of p-acetoxyacetophenone, 17.1 g (0.17 mole) of acetic anhydride, 65 g (1.08 moles) of acetic acid, 0.51 g (0.002 mole) of Co(OAc)2.4H2 O, 0.50 g (0.002 mole) of Mn(OAc)2.4H2 O, and 0.68 g (0.004 mole) of 48% HBr were combined in a glass reactor and heated to 100 C. Air was introduced at a rate of 50 ml/min. After 164 hours of reaction time, the oxidation ceased. Analysis of the reaction solution showed 3.4 wt % p-acetoxyacetophenone and 2.7 wt % p-hydroxyacetophenone. In addition, p-acetoxybenzoic acid and p-hydroxybenzoic acid were present in substantial amounts. An additional 30 g (0.294 mole) of acetic anhydride were added and the oxidation reaction continued. Final reaction time was 240 hours. Analysis of the final reaction mixture showed 41 mole % yield of p-acetoxybenzoic acid, 3.9 mole % yield of p-hydroxybenzoic acid, and 1.0 mole % yield unreacted p-acetoxyacetophenone.
42.9 g of 4-acetoxybenzoic acid and 0.2 g of pyridine were added to 430 mL of toluene and stirring was performed under a nitrogen atmosphere at 60 C. 34.0 g of thionyl chloride was added dropwise thereto. After dropwise addition, stirring was performed at 60 C. for 4 hours. Toluene was distilled off under a reduced pressure. The obtained residue was added to 230 mL of toluene and stirred while cooling under a nitrogen atmosphere. A 200 mL toluene solution in which 20.0 g of methyl 2,5-dihydroxybenzoate and 33.7 g of triethylamine were dissolved was added dropwise thereto. After dropwise addition, stirring was performed for 4 hours at room temperature. Water was added to the stirred solution and an organic layer was extracted. Next, the organic layer was washed with water and dried with anhydrous magnesium sulfate. Toluene was distilled off under a reduced pressure, and the residue was purified through column chromatography and recrystallization was performed with a mixture (v/v=1/4) of ethyl acetate and heptane to obtain 42.9 g of a compound (ex-1). Here, the packing of the chromatography column was silica gel. Here, the eluent was a mixture (v/v=9/1) of toluene and ethyl acetate.
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