Abstract: A process is described for obtaining high-purity 1-butene starting from C4 hydrocarbon mixtures containing isobutene, n-butane, isobutane, 1,3-butadiene, 1-butene, 2-butenes and also optionally C3 and C5 hydrocarbons, comprising the following stages: conversion of isobutene effected in a double stage, wherein each stage consists of one or more reactors followed by a distillation column for the recovery of the reaction product; recovery of the excess alcohol; recovery of 1-butene using at least two distillation columns; characterised in that it also uses a further conversion stage, consisting of one or more reactors in series, for completing the isobutene removal.

Abstract: Process for the production of high-purity isobutene starting from a stream prevalently containing MTBE (Methyl-Tert Butyl Ether) or ETBE (Ethyl-Tert Butyl Ether) which essentially comprises the following areas in sequence: • a fractionation area for obtaining a stream of high-purity MTBE or ETBE; • a cracking area of said stream of MTBE or ETBE for obtaining an outgoing stream prevalently containing isobutene and the relative alcohol, methanol or ethanol; • a washing area with water of the stream leaving the cracking area for the recovery of the relative alcohol, in order to obtain a stream containing isobutene, the ether fed and light compounds and a stream substantially consisting of water and relative alcohol, with a relevant fractionation section for separating the washing water to be recycled to the same washing area from the relative alcohol; • a fractionation area of the stream containing isobutene, the ether fed and light compounds for separating a stream of high-purity isobutene.

Abstract: A tubular reactor is described, for catalytic reactions involving thermal exchanges, in particular for etherification reactions between branched olefins and linear alcohol, for dimerization reactions of branched olefins or cracking reactions, essentially consisting of a vertical tube-bundle exchanger whose tubes contain catalyst, having inlet and outlet nozzles for each passage side of the reagents, catalyst and thermal exchange liquid, characterized in that it has one or more metallic supports situated outside the lower tube plate in the lower part of the reactor for sustaining the catalyst so that the same catalyst is contained not only in the tubes of the tube-bundle but also in said lower part outside the lower tube plate and also in the upper part outside the upper tube plate.

Abstract: Process for the production of high-purity isobutene starting from a stream prevalently containing MTBE (Methyl-Tert Butyl Ether) or ETBE (Ethyl-Tert Butyl Ether) which essentially comprises the following areas in sequence: a fractionation area for obtaining a stream of high-purity MTBE or ETBE; a cracking area of said stream of MTBE or ETBE for obtaining an outgoing stream prevalently containing isobutene and the relative alcohol, methanol or ethanol; a washing area with water of the stream leaving the cracking area for the recovery of the relative alcohol, in order to obtain a stream containing isobutene, the ether fed and light compounds and a stream substantially consisting of water and relative alcohol, with a relevant fractionation section for separating the washing water to be recycled to the same washing area from the relative alcohol; a fractionation area of the stream containing isobutene, the ether fed and light compounds for separating a stream of high-purity isobutene.

Abstract: A process is described for obtaining high-purity 1-butene starting from C4 hydrocarbon mixtures containing isobutene, n-butane, isobutane, 1,3-butadiene, 1-butene, 2-butenes and also optionally C3 and C5 hydrocarbons, comprising the following stages: conversion of isobutene effected in a double stage, wherein each stage consists of one or more reactors followed by a distillation column for the recovery of the reaction product; recovery of the excess alcohol; recovery of 1-butene using at least two distillation columns; characterised in that it also uses a further conversion stage, consisting of one or more reactors in series, for completing the isobutene removal.

Abstract: A tubular reactor is described, for catalytic reactions involving thermal exchanges, in particular for etherification reactions between branched olefins and linear alcohol, for dimerization reactions of branched olefins or cracking reactions, essentially consisting of a vertical tube-bundle exchanger whose tubes contain catalyst, having inlet and outlet nozzles for each passage side of the reagents, catalyst and thermal exchange liquid, characterized in that it has one or more metallic supports situated outside the lower tube plate in the lower part of the reactor for sustaining the catalyst so that the same catalyst is contained not only in the tubes of the tube-bundle but also in said lower part outside the lower tube plate and also in the upper part outside the upper tube plate.

Abstract: An integrated process for the simultaneous production of alkyl tert-butyl ethers and 1-butene, comprising feeding a C.sub.4 hydrocarbon stream to an etherification unit and recycling the remaining stream to the same unit after possible separation of the 1-butene and treatment in an isomerization section to convert the remaining butenes into isobutene, a molecular sieve separation unit operating with the hydrocarbons in the vapour phase being incorporated into the cycle.