Abstract: Process for producing very pure olefins of the formula ##STR1## by decomposition of the corresponding ethers of formula ##STR2## wherein R.sub.1 and R.sub.3 are selected from the group of the alkyl, arylalkyl aryl or alkylaryl radicals, R and R.sub.2 being a hydrogen atom or a radical selected from said above mentioned group, in the presence of steam in a molar proportion from 2 to 8 times the ether amount and with the use of a catalyst comprising alumina to which is added 0.01 to 5% by weight of titanium or zirconium or hafnium as metal or as metal compound, said catalyst having a specific surface from 80 to 300 m.sup.2 /g.

Abstract: Methyl tert.butyl ether is obtained by reacting an isobutene-containing C.sub.4 cut with methanol and distilling the reaction product at a superatmospheric pressure of 7-30 atm. abs. to recover a top fraction and a bottom fraction containing methyl tert.butyl ether. The isobutene conversion rate and the purity of the ether are increased by recycling a portion of the top fraction to the reaction zone.

Abstract: Process for producing gasoline of high octane number from C.sub.3 and C.sub.4 olefinic cuts, such as those obtained by fractional distillation of a C.sub.3 / C.sub.4 catalytic cracking cut, comprising the steps of:(a) oligomerizing propylene of the C.sub.3 cut to obtain a first gasoline fraction,(b) reacting the isobutene of the C.sub.4 cut with methanol to produce methyl tert.-butyl ether which is separated from the unreacted C.sub.4 hydrocarbons to form a second gasoline fraction,(c) alkylating said unreacted C.sub.4 hydrocarbons with isobutane in the presence of an alkylation catalyst such as hydrofluoric acid, to form a third gasoline fraction, and(d) admixing, at least partially, said first, second and third gasoline fractions, so as to obtain gasoline of high octane number.

Abstract: High octane gasoline is obtained from C.sub.3 /C.sub.4 olefinic cuts by a combination of steps: oligomerization of the C.sub.3 fraction, hydroisomerization of 1-butene in the C.sub.4 cut, fractionation of the resultant C.sub.4 cut, hydrogenation of isobutene and alkylation. Resultant fractions are admixed to produce the desired high octane gasoline.

Abstract: Lead free gasoline of high octane number is obtained from C.sub.3 and C.sub.4 olefinic cuts as follows: propylene contained in the C.sub.3 cut is oligomerized, at least 80% of the isobutene and less than 40% of the n-butenes of the C.sub.4 cut are oligomerized to form an oligomerizate distilling in the gasoline range, which is separated from the unreacted C.sub.4 hydrocarbons, the latter are subsequently alkylated to form a gasoline fraction which can be admixed with the oligomerizates of the C.sub.3 and the C.sub.4 cuts to produce the desired high octane gasoline.

Abstract: An ether is prepared by reacting a selected olefin with an alcohol in a two reaction zone system: in the first reaction zone, the catalyst is dispersed in the liquid phase of the reactants and boiling of the mixture is avoided; in the second reaction zone, the catalyst is in a fixed bed. A cooled recycle stream is fed back to the first stage reactor. The catalyst is a sulfonated ion exchange resin in the acid form.

Abstract: For polymerizing unsaturated hydrocarbons into oligomers with acid catalysts, there are employed liquid catalyst compositions containing a Bronsted acid and a sulfone of formula R--SO.sub.2 --R', wherein R and R' are each separately a monovalent radical containing from 1 to 8 carbon atoms or form together a divalent radical having from 3 to 12 carbon atoms, the acid concentration being at least 10.sup.-.sup.5 moles per liter of sulfone and at most the saturation concentration without exceeding 5 moles per liter of sulfone. The catalysts may be dispersed in an inert hydrocarbon solvent and Lewis acids may also be added.