Abstract: Alkyl tert.-alkyl ethers can be cleaved into the underlying alkanols and tert.-olefins in the presence of strongly acidic substances in a column apparatus, the strongly acidic substance being made available at the foot of the column. A particularly advantageous process design results when a water stream is fed below the top column tray in countercurrent to the tert.-olefin flowing upwards and is taken off again from the column above the bottom circulation; in the case of using an insoluble, strongly acidic substance, the latter is located in a catalyst bed at the foot of the column, and the alkyl tert.-alkyl ether is preferably fed in between the catalyst bed and the bottom circulation evaporator.

Abstract: Gum-free fuel components containing alkyl tert.-alkyl ethers have been found which can be prepared by reacting a crude hydrocarbon mixture containing gum-forming constituents and containing one or more tert.-olefins, simultaneously with alkanols and H.sub.2 on a certain exchanger in the H.sup.+ form containing one or more metals of sub-group VI, VII or VIII of the periodic table of the element in element form, in the liquid phase at 30.degree. to 140.degree. C.

Abstract: Alkenes having a terminal double bond can be isomerized to give alkenes having an internal double bond if alkenes having a terminal double bond or hydrocarbon feedstock having a content of alkenes of this type having a terminal double bond are subjected to treatment, in the presence of hydrogen, over a macroporous or gel-like cation exchanger in the H.sup.+ form which contains 0.001 to 10 g of one or more metals of the VIth and/or VIIth and/or VIIIth sub-group of the periodic system of the elements in elementary form per liter of dry cation exchanger and which has a degree of crosslinking of 2 to 65% and a specific surface area of 5 to 750 m.sup.2 /g of dry exchange resin. The treatment is carried out in the liquid phase at a temperature from 0.degree. to 120.degree. C.

Abstract: A process and apparatus for the separation of components from a mixture which forms an azeotrope is disclosed by subjecting the mixture to extractive distillation to remove one of the components and regeneration to separate another component from the extracting agent added to the extractive distillation column. According to the invention, a first side stream is withdrawn from the extractive distillation column, passed in heat exchange with the bottoms from the extractive distillation column en route to the regeneration column and returned to the extractive distillation column at a point below the point at which it is withdrawn. A second side stream from the extractive distillation column is withdrawn, passed in heat exchange with the bottoms of the regeneration zone and returned to the extractive distillation column. For this purpose, separate heat exchangers are used for the respective side streams.

Abstract: In a process for the preparation of an alkyl tert.-alkyl ether by reaction of an isoolefin branched at the double bond and an alkanol in the presence of a cation exchanger, the improvement which comprises:(a) Employing as the cation exchanger a macroporous or gelatinous acid cation exchanger in the H.sup.+ form which has been charged with 0.1 to 5 grams, per one liter of dry cation exchanger, of an elementary form of a metal of sub-groups VI, VII or VIII of the periodic table of elements (Mendeleev) which cation exchanger is crosslinked with the degree of crosslinking of 2 to 65% and has a specific surface area of 5 to 750 square meters per gram on the basis of dry cation exchange resin; and(b) The reaction is carried out in the liquid phase at a temperature of 30.degree. to 140.degree. C. at a pressure of 2 to 100 bars employing a molar ratio of isoolefin to alkanol of 0.1 to 5.