NOVELTY - Production of triptane and/or triptene involves contacting a reaction composition comprising methanol and/or its derivatives, at least one olefin, and optionally at least one further alcohol and/or their derivatives with a zeolite catalyst having bronsted acidity at a temperature of 150-400 degrees C to produce triptane and/or triptene.    USE - For production of triptane and/or triptene (claimed) useful in gasoline formulation.    ADVANTAGE - The zeolite catalysts having bronsted acid character provides a combination of high triptyl yields and high fractions of triptyl compounds. The process produces triptyl yield of greater than or equal to 0.8%, and triptyl fraction of greater than 5%. As the crystalline aluminosilicate catalyst does not comprise halide ions, the problems associated with halide contamination of the product and halide-induced corrosion in process equipment can be avoided. The zeolites of structure type (i) results in a combination of higher triptyl yields and higher triptyl fractions in the 7C hydrocarbon compared to zeolites that do not adopt either the type (i) or type (ii) structures. For zeolites of structure type (ii), zeolites comprising at least one alkali-metals show improved combination of higher triptyl yields and fractions compared to those that do not adopt either the type (i) or (ii) structures. The use of biologically-derived feedstocks results in the triptane having a lower impact on atmospheric CO2 (carbon dioxide)-emissions when combusted, because biomass ultimately derives from atmospheric CO2. The alcohol and/or ether-containing product stream (including methanol and/or dimethyl ether) does not need to be treated to remove higher alcohols and/or ethers. Using the catalysts, it is possible to obtain a combination of triptyl yields of greater than or equal to 0.8% and a triptyl fraction of greater than 5% (where the triptyl yield is expressed as a percentage of all the carbon in the reaction composition, excluding any carbon associated with inert diluent, and the triptyl fraction is expressed as a percentage of 7C hydrocarbons produced in the reaction).    DETAILED DESCRIPTION - Production of triptane and/or triptene involves contacting a reaction composition comprising methanol and/or its derivatives, at least one olefin, and optionally at least one further alcohol and/or its derivative with a zeolite catalyst having bronsted acidity at a temperature of 150-400 degrees C to produce triptane and/or triptene. The catalyst having bronsted acidity is selected from at least one of the following: i) zeolites having frameworks comprising silicon and aluminum atoms and having a channel structure comprising a ring size of greater than or equal to 12 non-oxygen framework atoms in 2 or 3 dimensions; and ii) alkali metal containing zeolites having frameworks comprising silicon and aluminum atoms and which have a framework ring comprising greater than or equal to 12 non-oxygen atoms accessible on the external surface of the zeolite, and a channel structure in which all of the channels have a ring-size of less than 12 non-oxygen framework atoms.