Abstract: The invention relates to a process for preparing isocyanates by reacting amines with phosgene in the gas phase in a reaction zone, with the reaction mixture being passed through a zone into which a liquid is sprayed to stop the reaction, wherein the reaction mixture is passed through a zone having a reduced flow cross section between the reaction zone and the zone into which the liquid is sprayed.

Abstract: A three-dimensional flow cell for aligning non-isometric particles in a liquid sample in two axes, a method of aligning non-isometric particles in a liquid sample, a reflectance sensor which has the three-dimensional flow cell according to the invention, a method of measuring the reflectance of a liquid sample containing non-isometric particles and the use of the reflectance sensor according to the invention.

Abstract: Method of regulating the process for the continuous free-radical polymerization of ethylene in the presence or absence of comonomers in a tube reactor having at least one reaction zone (1, 2, 3, 4) at pressures above 1000 bar and temperatures in the range from 100 to 400° C.

Abstract: In a process for preparing polyethylene in tube reactors with or without autoclaves, where a free-radical initiator is introduced with or without cold ethylene into a flowing ethylene- and comonomer-containing medium, rotation is generated between two streams (61, 62) to be mixed at an angle (66) or by provision of a swirl element (20, 80) in the flow cross section (27, 28). In the region of a feed point (72, 81) for a free-radical initiator, there is provided a cross-sectional constriction (63, 67, 71) at which the free-radical initiator is introduced through an optimized off-center outlet opening (44) of an introduction finger (40) into the rotating flow (61, 62, 70).

Abstract: The invention relates to a method for the continuous production of ethylene homo- and ethylene co-polymers in the presence of radical polymerisation initiators and, optionally, molecular weight regulators in a tubular reactor with a hot water jacket and one or several reaction zones at pressures of 1000 to 4000 bar and temperatures of 120° C. to 350° C. The hot water jacket of each reaction zone is divided into two independently-controllable, separate, longitudinal sections and the water exit temperature from the tubular jacket of the first longitudinal section per reaction zone, extending between the point of initiator addition and 20 to 50% of the reaction zone length, is set to 180° C. to 210° C. and in the following second longitudinal section of said reaction zone the hot water exit temperature from the tube jacket is set to 140° C. to 180° C.

Abstract: The invention relates to a method for producing ethylene homo- and copolymers in a tubular reactor at pressures above 1000 bar and temperatures in the range from 120 to 350° C. by free-radical polymerization, in which firstly small amounts of free-radical chain initiators are added to a mobile flow medium comprising ethylene, molecular weight regulator and optionally polyethylene, and the polymerization is then carried out.

Abstract: The invention relates to a method for the continuous production of ethylene homo- and ethylene co-polymers in the presence of radical polymerisation initiators and, optionally, molecular weight regulators in a tubular reactor with a hot water jacket and one or several reaction zones at pressures of 1000 to 4000 bar and temperatures of 120° C. to 350° C. The hot water jacket of each reaction zone is divided into two independently-controllable, separate, longitudinal sections and the water exit temperature from the tubular jacket of the first longitudinal section per reaction zone, extending between the point of initiator addition and 20 to 50% of the reaction zone length, is set to 180° C. to 210° C. and in the following second longitudinal section of said reaction zone the hot water exit temperature from the tube jacket is set to 140° C. to 180° C.