Abstract: A process for the preparation of methyl tertiary butyl ether (MTBE) in two stages:the first stage comprising the reaction of isobutene with methanol in the presence of an acid catalyst, yielding MTBE, while the second stage comprises firstly the conversion of normal-butenes present in the hydrocarbon flow, which remains behind after separation of the MTBE formed in the first stage into isobutene and secondly passing the mixture thus obtained to a reaction zone to form MTBE.Optionally an extra amount of methanol can be supplied to said reaction zone. Said reaction zone can be the same as that used in the same first stage or another one.

Abstract: A process for recovering maximum amounts of styrene from hydrocarbon fractions produced by thermal cracking of hydrocarbons. The cracked products are subjected to quench cooling and in a separating column separated into a bottom fraction comprised predominantly of hydrocarbons with 9 and more carbon atoms and into a top fraction comprised predominantly of hydrocarbons having less than 9 carbon atoms. The top fraction is fed to a cooling and separating device wherein a cracked gasoline fraction is recovered from which fraction styrene is recovered by fractionation. The cracked gasoline fraction from the separating device can be combined with the hydrocarbon condensates from the first and second compressor stages of a multistage compressor in which the vaporous fraction from the cooling and separating device is compressed.

Abstract: The invention is directed to a process for preparing cyanic acid from urea, comprising atomizing urea in a tubular reactor in the presence of a stream of a carrier gas to obviate the formation and deposition of by-products on the inner walls of the tubular reactor, thereby increasing the efficiency and production yields of the process.

Abstract: An improved urea synthesis process is disclosed in which carbon dioxide and ammonia are reacted at 210.degree. to 245.degree.C under pressures of 250 to 600 atm., the gross molar NH.sub.3 /CO.sub.2 ratio in the liquid phase in the synthesis zone of the order of 2.5 and 8, the carbon dioxide and ammonia being reacted together in a synthesis zone then the resulting urea synthesis solution being stripped in a stripping zone which is in heat exchange relation with the synthesis zone through a wall, and the gas mixture resulting from the stripping is partially recycled to the synthesis zone.

Abstract: Cyanates of alkali and alkaline-earth metals are prepared by reacting a salt such as the hydroxide, carbamate or carbonate of the metal in aqueous solution or slurry with cracked urea gas which is a gaseous mixture of ammonia and (iso)cyanic acid.

Abstract: Ammonium carbamate is decomposed and removed in the form of its gaseous components by contacting a urea synthesis solution comprising the carbamate with a stripping gas, such as carbon dioxide, the countercurrent stripping conducted at adiabatic conditions in the stripper unit. Urea synthesis solution to be treated is supplied at higher pressures and temperatures, at least 205.degree.C and at a pressure of at least 225 atm. Conveniently, the decomposition of the ammonium carbamate and the removal of the liberated gases are carried out at these temperatures and pressures so that the stripper is operative under the same conditions as well.