Bisphenol catalytic activity

Solid acid catalysts, consisting of polysiloxane bearing alkylsulfonic acid groups (MCM-41), are comparable in their catalytic activity to those of the polystyrene-based cation exchange resins. These catalysts can be used in the preparation of para-Bisphenol-A by the alkylation of phenol with acetone. Other application of these catalysts lie in the alkylation of phenol with isobutene at 90-130 O . 

A co-catalytically active mercapto group was incorporated within the polysiloxane matrix. The desired 4,4 -bisphenol-A is produced with a selectivity of 95-96% whereas the total selectivity for the 4,4 - and 2,4 -bisphenol-A is higher than 99%. These results are achieved with extremely short residence times as compared to the state-of-the-art technology. Whereas the use of polystyrene resins gives selectivities of about 4 to 5% less at WHSV = 0.2 - 0.5 h, the above reported excellent selectivities obtained with the Deloxan catalysts are reached at space velocities from 0.5 up to 2.0 h". ... 

According to this mechanism, acetone undergoes the sequential activation, first by the protonation and then by the thiol attack. Thus, the highly electrophilic propylidene sulphonium intermediate is created, which successively reacts with phenol molecules. The functional groups are distributed on the catalyst surface near each other, and, they are also located close to the pore walls. Such location of the functional groups significantly increases the catalytic activity of the silica material SBA-15 and provides the steric driving force that favors the formation of the p,p isomer of Bisphenol-A. 

By increasing the amount of the catalyst, regardless of its structure, the reaction rate was raised but only up to a certain level above which increase in the quantity of the catalyst used, did not enhance the polymerization rate to any appreciable extent, see Fig. 3. At this threshold level of catalyst the supply of bisphenolate anions by the catalyst to reaction site apparently becomes equal to or exceeds their consumption rate through polymer-zation. The results shown in Fig. 2 and 3 imply that the catalytic activity, being judged by polymer yield, was P r">Q" r">DBC. 

Sulfonic add-functionalized PMO was well prepared by Li et al. All PMOs having sulfonic acid exhibited high catalytic activity in the condensation of phenol with acetone. Bisphenol A is a product from this reaction and a very important material for the production of resins and polymers. Additionally, they found a difference in catalytic activity according to organic component in framework. Sulfonic add-functionalized ethylene PMO exhibited higher catalytic activity than sulfonic add-functionalized phenyl PMO because of the former s high surface area and large pore diameter [88]. 

Block copolymers comprising carbonate and arylene ether blocks have been prepared by the catalytic decarboxylation of random or alternating copolycarbonates. This novel route to block copolymers is catalyzed by a number of catalysts and requires only that one of the bisphenols in the starting copolycarbonates be activated by electron-withdrawing substituents, e.g. 4,4 -dihydroxydiphenyl sulfone (bisphenol S), or 4,4 -dihydroxybenzophenone (bisphcnol K). 

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