Abstract: A crystallized aromatic polycarbonate having a weight average molecular weight of from 6,000 to 200,000 and having a terminal hydroxyl group content of not greater than 0.03% by weight based on the weight of the polycarbonate is effectively produced by first heating a mixture of a dihydroxydiaryl compound comprising at least 85 mole % of a dihydroxydiaryl alkane with a diaryl carbonate to prepare a prepolymer having a weight average molecular weight of from 2,000 to 20,000 and having terminal aryl carbonate groups in an amount of greater than 50 mole %, based on the total number of moles of all the terminal groups of the prepolymer, secondly crystallizing the prepolymer and finally subjecting the crystallized prepolymer to solid-state polymerization. The crystallized aromatic polycarbonate does not contain impurities, is colorless and has excellent properties such as resistance to heat and to boiling water. Therefore, the polycarbonate is advantageously used as engineering plastics.

Abstract: In the preparation of methacrylonitrile by gas-phase ammoxidation of isobutylene or tertiary butanol, the reaction is carried out (A) (i) using a catalyst system consisting essentially of (1) 30-70% by weight of a silica catalyst carrier and (2) a catalyst material having a composition represented by the formula:A.sub.0.05-1.0 Mo.sub.12 Bi.sub.1-18 Fe.sub.2-10 Na.sub.0-3.6 P.sub.0-3 O.sub.xwherein A is at least one element selected from the group consisting of potassium, rubidium and cesium, and x is the number of oxygen atoms needed to satisfy the valence requirements of the other elements present, said catalyst system having a specific surface area of 2-10 m.sup.2 /g; (ii) at a temperature of 380.degree.-480.degree. C.; (iii) at a contact time of 1-10 seconds; and (B) while maintaining the oxygen concentration in the gaseous reaction mixture below about 1 percent by volume.

Abstract: Malononitrile is prepared in a high yield by catalytic oxidative dehydrogenation of .beta.-aminopropionitrile in a gaseous phase with molecular oxygen in the presence of a catalyst, comprising a oxide composition of, preferably, Mo and at least one other catalytic element, more preferably, of the empirical formula (I):Mo.sub.12 Bi.sub.0.1-24 A.sub.a B.sub.b C.sub.c D.sub.d O.sub.x (I)wherein A=Fe and/or Cr, B=Ni, Co, Mn and/or Mg, C=alkali metals, alkaline earth metals, rare earth metals, Te, Tl, W and/or Pb, a=0.1-24, b=0-24, c=0-2 and d=0-5.

Abstract: A catalyst composition having a composition represented by the formula:A.sub.0.1-4 B.sub.0.02-1 Mo.sub.12 Bi.sub.0.5-10 Fe.sub.0.5-10 Na.sub.0-3 P.sub.0-2 O.sub.gwherein A is at least one element selected from the group consisting of cerium, lanthanum, neodium, praseodium, samarium, europium and gadrinium, B is at least one element selected from the group consisting of potassium, rubidium and cesium, and g is the number of oxygen atoms required to satisfy the valence requirements of the other elements present, and supported on silica.

Abstract: A process for the preparation of acrylonitrile by the ammoxidation reaction of propylene, characterized by using an oxide type catalyst which contains, as active ingredients, molybdenum, bismuth, iron and at least one element selected from potassium, rubidium and cesium in specifically limited proportions and which may further contain sodium and/or phosphorus. By the use of such a specific catalyst, the selectivity for the desired acrylonitrile is remarkably improved, and there can be attained high yield of the product. In the process of the present invention, the catalyst can maintain a high activity and a high selectivity for a long time, without undergoing attrition. The catalyst is well prevented from sublimation-escaping of the ingredient molybdenum therefrom.