Acrylic acid surface area

The addition of water to the reaction feed was investigated [136]. This led to two significant effects being noted. The selectivity to maleic anhydride increased (with increased yields of acetic and acrylic acids). There was also an increase in the surface area of the catalysts activated with the n-butane/water/air feed compared to the dry activated catalyst Arnold and Sundaresan excluded the possibility of the water vapor acting as a diluent by performing experiments with an n-butane/N2/air feed. Instead they proposed that water is adsorbed onto the surface, blocking sites that are responsible for over-oxidation of the products. 

Comparisons of commonly used XAD resins have been published for the isolation of both fulvic acid (Aiken et al., 1979) and humic acid (Cheng, 1977) from water. These resins differ in pore size, surface area, polymer composition, and polarity (Table 5) (Kunin, 1977). As with anion-exchange resins, hydrophobic styrene-divinylbenzene resins (XAD-1, XAD-2, XAD-4) were found more difficult to elute than hydrophilic acrylic-ester resins (Table 6). This is due to hydrophobic interactions, and possible tt-tt interactions with the aromatic resin matrix of styrene-divinylbenzene resins. In addition, ki-... 

The results obtained by N2 adsorption are presented in table 3, as well as 6TOC/S (TOC variation as a function of unit area) obtained for acrylic acid oxidation. MnCe7 and CoCe7 have the highest surface areas. On the other hand, Mn Ox exhibited the lowest value, only 32 m /g while all other surface areas were higher than 91 mVg. Nevertheless, the TOC variation per unit of surface area achieved with Mn Ox is the highest of all. 

Schneider proposed the use of high surface area vanadium phosphates with a PA atomic ratio of 1.0 to 1.5 that had been developed as catalysts for oxidation of n-butane to maleic anhydride. The reaction is conducted at a temperature of 360 °C, an SV of 400 h and an acetic acid/water/HCHO molar ratio of 10/2.8/1, using formalin as the source of HCHO. The single-pass yield of acrylic acid reaches 84 mol% based on the charged HCHO (8.4 mol% based on acetic acid) at the conversion of 98% selectivity is 86 mol% based on HCHO. 

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