Abstract: For the purification of the norbornene obtained by the reaction of dicyclopentadiene or cyclopentadiene and ethylene, the crude reaction mixture containing light impurities having boiling temperatures lower than that of norbornene; medium-heavy impurities having the boiling temperatures between that of norbornene and that of ethylnorbornene; and heavy impurities containing ethylnorbornene and compounds boiling higher than ethylnorbornene, boiling temperatures greater than that ethylnorbornene, a first distillation of the crude reaction mixture is carried out in a tailing column (C1), removing a portion of the heavy impurities and a portion of the medium-heavy impurities; then a second distillation of the crude mixture, thus tailed, is carried out in a topping column (C2), removing the light impurities; and a third distillation of the mixture, thus topped, is subsequently carried out in a tailing column (C3), removing the remainder of the heavy and medium-heavy impurities.

Abstract: This process for the manufacture of norbornene from dicyclopentadiene (DCPD) and ethylene is characterized in that the DCPD is subjected to partial monomerization to CPD by preheating: at a temperature of 140° C. to 240° C.; and under a pressure of 20 to 300 bar abs., before reacting it with the ethylene; with an ethylene/DCPD molar ratio of 1 to 20; at a temperature of 200° C. to 320° C.; under a pressure of 20 to 300 bar abs.; and with a residence time of 1 to 10 minutes, under stable reaction conditions between the DCPD, the CPD and the ethylene.

Abstract: An improved method for the selective vapor phase oxidation of propylene to acrolein in a recirculating solids reactor system using a bismuth molybdate multimetal oxide involving specific reactant concentrations (preferably 5 mol % to 30 mol % propylene, 0 to 20 mol % oxygen, and the remainder inert gas), particle size (1 to 300 micrometers), temperature (250 to 450° C.) and gas (1 to 15 seconds) and solids (2 to 60 seconds) residence times. Such a process leads to improved selectivity and propylene conversion.

Abstract: An improved method for the selective vapor phase oxidation of acrolein to acrylic acid in a recirculating solids reactor system using a particulate molybdenum vanadate multimetal oxide as oxidant involving specific reactant concentrations (preferably 5 mol % to 30 mol % propylene, 0 to 20 mol % oxygen, 0 to 70 mol % water, and the remainder inert gas), solids particle size (20 to 300 micrometers), temperature (250 to 450° C.) and gas (1 to 15 seconds) and solids (2 to 60 seconds) residence times. Such a process leads to improved selectivity, conversion and solids conversion ratio.

Abstract: An improved method for manufacturing acrylic acid by vapor phase oxidation of propylene in a single step or reaction stage using as solid phase oxidant a mixture of two particulate solids comprising a bismuth molybdate multimetal oxide (e.g., Mo12Co3.5Bi1.1Fe0.8W0.5Si1.4K0.05Ox) and a molybdenum vanadate multimetal oxide (e.g., Mo12V4.8Sr0.5W2.4Cu2.2Ox). Such a process is advantageously carried out in a recirculating solids reactor system wherein the particulate mixture of solids in an oxidized state reacts with a feed gas containing propylene in a vertical riser reactor and after separation from the acrylic acid gaseous product the particulate mixture of solids in a reduced state is regenerated by contact with an oxygen containing gas in a separate regeneration reactor before recirculation to the riser for further reaction.

Abstract: Apparatus for concentrating and dehydrating maleic acid to form maleic anhydride, comprising: at least a first and a second vertical, independent and distinct, falling thin-film, multitubular evaporators of the static type arranged in series, wherein the first thin-film multitubular evaporator of the static type has an upper part and a lower part and includes a feedpipe at the upper part and a discharge pipe at the lower part; a separator connected by its sidewall to the discharge pipe from the first evaporator and including a first discharge pipe at the upper portion thereof and a second discharge pipe at the lower part; the second thin-film multitubular evaporator of the static type having a feedpipe having an upper part and a lower part connected to the second discharge pipe from the separator and including a discharge pipe only at the lower part thereof; a boiler having an upper part and a lower part, said upper part of said boiler being connected to and in open communication with the lower portion of the

Abstract: A distribution cap for a multitubular falling heat exchanger, in which the exchanger has a bundle of parallel tubes, an entrance channel for the tubes and a perpendicularly disposed distribution plate surrounding the entrance end of the tubes, the distribution cap is located in the entrance channel above the distribution plate and over the entrance ends of the tubes, and has cylindrical sidewalls and a closed top having sides that slope downwardly toward the cylindrical sidewalls of the cap.

Abstract: In the dehydration of maleic acid to form maleic anhydride, comprising a first stage of concentrating an aqueous solution of maleic acid to 85-95% by maleic acid, and a second stage of dehydrating the concentrated maleic acid into maleic anhydride, in at least one of the stages, a falling film tubular evaporator is employed. Prior to the dehydration stage, about 15-35 parts by weight of maleic anhydride is added per 10 parts of concentrated acid.