Abstract: The present invention relates to a method for producing dehydro rose oxide by reacting isoprenol and prenal in the presence of at least one sulfonic acid of formula R1—SO3H as catalyst, wherein R1 is selected from phenyl which carries 2 or 3 C1-C4-alkyl substituents, phenyl which carries one C8-C20-alkyl substituent and optionally also 1 or 2 C1-C4-alkyl substituents, and naphthyl which optionally carries 1 or 2 C1-C4-alkyl substituents.

Abstract: The present invention relates to a method for producing dehydro rose oxide by reacting isoprenol and prenal in the presence of at least one sulfonic acid of formula R1—SO3H as catalyst, wherein R1 is selected from phenyl which carries 2 or 3 C1-C4-alkyl substituents, phenyl which carries one C8-C20-alkyl substituent and optionally also 1 or 2 C1-C4-alkyl substituents, and naphthyl which optionally carries 1 or 2 C1-C4-alkyl substituents.

Abstract: A blow extruder for producing hoses made of plastic material has, at the outlet of its nozzle arrangement for producing hoses, a cooling air nozzle ring which encompasses hoses exiting from the nozzle arrangement and to which air is delivered from a blower. An apparatus for cooling air delivered to the cooling air nozzle ring includes a direct evaporator provided with a refrigeration plant and arranged between the blower and the cooling air nozzle ring. The direct evaporator includes a plate fin element and an injection device for a cooling agent and hot air. The cooling apparatus further includes a regulation device for controlling the temperature of the cooling air by controlling operation of the cooling apparatus.