Abstract: A diphenylsulfone compound containing 4,4?-dihydroxydiphenylsulfone is produced in good yield in a short time and at a relatively low temperature. A diphenylsulfone compound represented by formula (2) below is produced by irradiating, with microwaves, a compound represented by formula (1) below and a sulfonating agent so that a dehydration condensation reaction is carried out.

Abstract: An object of the present invention is to provide a method for industrially advantageously manufacturing a sulfonated aromatic polymer while preventing a reduction in the molecular weight of the resulting sulfonated aromatic polymer. The present invention relates to a method for manufacturing a sulfonated aromatic polymer, comprising sulfonating an aromatic polymer and a sulfonating agent in the presence of a solvent of a compound containing a sulfonyl group (—SO2—).

Abstract: An organic-solvent dispersion containing fine polysilsesquioxane particles stably dispersed therein, which is obtained by adjusting the pH of an aqueous dispersion of fine polysilsesquioxane particles to 2 to 9, subsequently adding an organic solvent thereto, and then removing the water from the system; and an aqueous dispersion of fine polysilsesquioxane particles having an appropriate average particle diameter, which is obtained by adjusting the amount of a base catalyst to be used so as to be in a specific range. The process for producing an aqueous dispersion of fine polysilsesquioxane particles having a pH of 2 to 9 with an organic solvent.

Abstract: The present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of very high purity. In particular, the present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of high purity comprising the steps of subjecting phenol in combination with a sulfonating agent or phenolsulfonic acid to a dehydration reaction in the presence of an aromatic nonpolar solvent while suspending the resulting dihydroxydiphenylsulfone therein, mixing the reaction suspension with a polar solvent to at least partially dissolve the dihydroxydiphenylsulfone, and precipitating 4,4?-dihydroxydiphenylsulfone.

Abstract: The present invention provides a process for producing dihydroxydiphenylsulfone wherein trihydroxytriphenylsulfone and coloring impurities are effectively removed without altering the isomeric composition of dihydroxydiphenylsulfone. In particular, the present invention provides a process for producing dihydroxydiphenylsulfone comprising the steps of dissolveing or suspending in an aqueous solvent crude dihydroxydiphenylsulfone containing trihydroxytriphenylsulfone, adjusting the pH to 5–7, optionally cooling, and separating the crystalline dihydroxydiphenylsulfone thus precipitated.

Abstract: The present invention provides a process for producing a mixture of dihydroxydiphenylsulfone isomers containing 2,4?-dihydroxydiphenylsulfone, the process comprising heating 4,4?-dihydroxydiphenylsulfone or a mixture of dihydroxydiphenylsulfone isomers containing at least 85 wt. % of 4,4?-dihydroxydiphenylsulfone in the presence of phenol and sulfuric or sulfonic acid.

Abstract: The present invention provides a process for producing a mixture of 4,4?- and 2,4?-dihydroxydiphenylsulfones comprising heating trihydroxytriphenyldisulfone or a mixture of dihydroxydiphenylsulfone isomers containing trihydroxytriphenyldisulfone in the presence of phenol and an acid catalyst.

Abstract: A sulfonating agent represented by the general formula ##STR1## wherein the groups R.sup.1 are the same or different and are each a lower alkyl group having 1 to 3 carbon atoms, n is an integer of 3, 4 or 5, m is an integer of 1 or 2, and n+m.ltoreq.6, and a process for sulfonating an aromatic compound with use of the sulfonating agent.

Abstract: A process for preparing 4,4'-dihydroxydiphenylsulfone, the process including heating 4,4'-dihydroxydiphenylsulfone and 2,4'-dihydroxydiphenylsulfone in the presence of an acid catalyst to isomerize the 2,4'-dihydroxydiphenylsulfone into 4,4'-dihydroxydiphenylsulfone, the process being characterized in that a suspension of 4,4'-dihydroxydiphenylsulfone and 2,4'-dihydroxydiphenylsulfone in a liquid dispersing medium is heated for isomerization while the liquid portion is distilled off or a crystal mixture of 4,4'-dihydroxydiphenylsulfone and 2,4'-dihydroxydiphenylsulfone is heated for isomerization to produce 4,4'-dihydroxydiphenylsulfone in the form of crystal powder.

Abstract: The present invention provides a process for preparing 4,4'-dihydroxydiphenylsulfone which comprises subjecting a phenol and a sulfonating agent to dehydration reaction in the presence of mesitylene as a reaction medium while the produced 4,4'-dihydroxydiphenylsulfone is suspended in the mesitylene, and a process for preparing 4,4'-dihydroxydiphenylsulfone, characterized in that after the foregoing dehydration reaction, the 4,4'-dihydroxydiphenysulfone obtained as suspended in the mesitylene and/or retained in a liquid-free solid form is subjected to reaction for isomerization of 2,4'-dihydroxydiphenylsulfone produced as a by-product into 4,4'-dihydroxydiphenylsulfone with heating at a temperature of not lower than that for isomerization of 2,4'-dihydroxydiphenylsulfone into 4,4'-dihydroxydiphenylsulfone.