Abstract: Particulate expandable styrene polymers contain homogeneously distributed graphite particles and can be processed to give self-extinguishing foams having a density of ≦35 g/l.

Abstract: In a process for preparing expandable styrene polymers containing graphite particles, styrene is polymerized in aqueous suspension in the presence of graphite particles.

Abstract: A continuous process for preparing bead-form expandable styrene polymers in which the styrene is prepolymerized in bulk to a conversion of 10 to 80%, the prepolymer is dispersed in liquid form in an aqueous phase in the presence of suspension stabilizers, and the polymerization of the prepolymer is completed in an aqueous suspension to a residual styrene content of less than 2000 ppm.

Abstract: Expandable styrene polymers containing recycled polystyrene have a content of recycled material of up to 40% by weight, based on the total weight of the polystyrene, wherein, in the course of the polymerization of the reaction mixture, from 100 to 500 ppm of a molecular weight regulator and/or from 0.05 to 1.0% by weight, based in each case on the polymerization solution, of a finely divided polyethylene wax are added.

Abstract: The invention relates to expandable styrene polymers containinga) a styrene polymer,b) and at least one carbon dioxide absorber, mixed or copolymerized with the above, in an amount of from 0.01 to 50% by weight, based on the sum of a) and b), andc) a blowing agent or blowing agent mixture in an amount of from 0.5 to 12% by weight,where the blowing agent or blowing agent mixture comprisesc.sub.1) from 10 to 100% by weight of carbon dioxide andc.sub.2) from 0 to 90% by weight of at least one further blowing agent.The invention furthermore relates to the styrene polymers containing a carbon dioxide absorber, to the styrene polymer foams obtainable from the expandable styrene polymers, and to an improved process for impregnating styrene polymers with carbon dioxide-containing blowing agents or blowing agent mixtures.

Abstract: The invention relates to expandable styrene polymers containinga) a styrene polymer,b) and at least one carbon dioxide absorber, mixed or copolymerized with the above, in an amount of from 0.01 to 50% by weight, based on the sum of a) and b), andc) a blowing agent or blowing agent mixture in an amount of from 0.5 to 12% by weight,where the blowing agent or blowing agent mixture comprisesc.sub.1) from 10 to 100% by weight of carbon dioxide andc.sub.2) from 0 to 90% by weight of at least one further blowing agent.The invention furthermore relates to the styrene polymers containing a carbon dioxide absorber, to the styrene polymer foams obtainable from the expandable styrene polymers, and to an improved process for impregnating styrene polymers with carbon dioxide-containing blowing agents or blowing agent mixtures.

Abstract: Wastewaters which contain carbon black and ash and originate from high temperature processes and in which the carbon black is present in a very finely divided state and partially in a colloidal state are treated and disposed of by a process in which the wastewater is treated with calcium carbonate or calcium hydroxide and an organic flocculant and subjected to a two-stage filtration and the resulting filter cake containing carbon black and ash is subjected to an aftertreatment with an aqueous iron salt solution.

Abstract: H.sub.2 S-containing gases are desulfurized by direct catalytic oxidation of the H.sub.2 S to elemental sulfur with an oxygen-containing gas at elevated temperatures by a method in which the catalyst used is a supported titanium dioxide catalyst containing from 0.1 to 25% by weight of nickel oxide and from 0 to 10% by weight of aluminum oxide, the percentages being based on the supported catalyst.

Abstract: Gases containing CO and/or CO.sub.2 are purified by removing sulfur compounds and other impurities by catalytic reaction at elevated temperatures by a process in which the gases to be purified are passed directly through a catalyst charge containing a Cu/ZnO catalyst prepared by thermal decomposition of a mixed crystalline compound of zinc hydroxide carbonate, and the space velocity is set at 500-5,000 m.sup.3 (S.T.P.) per m.sup.3 of catalyst per hour. Preferably, the catalyst used is a Cu/ZnO catalyst which is prepared by thermal decomposition of a catalyst precursor of the general formulaCu.sub.x Zn.sub.y (OH).sub.6 (CO.sub.3).sub.2.

Abstract: H.sub.2 S-containing gases are desulfurized by direct catalytic oxidation of the H.sub.2 S to elementary sulfur by means of oxygen-containing gases in a tube reactor, with indirect removal of the heat of reaction by means of a coolant and with condensation of the sulfur formed, wherein either the catalyst is present in the jacket space around the tubes and the coolant is present in the tubes of the reactor or the coolant is present in the jacket space around the tubes and the catalyst is present in the tubes of the reactor, and the catalyst fills the tubes of the tube reactor or the jacket space around the tubes over the entire cross-section of the tubes or the jacket space respectively, the exit temperature of the gaseous reaction mixture leaving the tube reactor is kept at 180.degree.-400.degree. C. and the sulfur formed in the tube reactor is separated out of the reaction mixture, obtained in the reactor, in a condensation stage downstream of the reactor.

Abstract: A process for preventing deposits in the pipes of waste heat boilers employed for cooling gases in the partial autothermal oxidation of fossil fuels to prepare hydrogen or synthesis gases, wherein the pipes are flushed, at the operating temperature, with hydrogen-containing gases which contain little or no H.sub.2 S.

Abstract: The compound Ni.sub.5 MgAl.sub.2 (OH).sub.16.sup.. CO.sub.3.sup.. 4H.sub.2 O is precipitated from an aqueous solution containing salts of nickel, magnesium and aluminum with a carbonate or bicarbonate of an alkali metal. After this catalyst precursor has been dried, calcined and reduced with hydrogen a catalyst can be prepared which is suitable for the cracking of hydrocarbons in the presence of steam. In the steam cracking of hydrocarbons the hydrocarbon and the steam may be reacted to form a gas rich in methane in contact with this catalyst at a preheating temperature of less than 300.degree. C.

Abstract: A two-stage process for the manufacture of methane from hydrocarbons is described. In the first stage, the hydrocarbons are converted into methane-rich gases, using the nickel catalyst described below. The cracked gases thus obtained are cooled and converted into methane-rich gases in a further catalytic process stage, using a methanization catalyst or the nickel catalyst mentioned below. To produce the nickel catalyst, the compound Ni.sub.6 Al.sub.2 (OH).sub.16.CO.sub.3.4H.sub.2 O is prepared in aqueous solution. The catalyst is obtained from this compound by drying, calcination and subsequent reduction in a stream of hydrogen whilst maintaining very specific temperature gradients between the drying stage and the calcination stage.

Abstract: The compound Ni.sub.6 Al.sub.2 (OH).sub.16. CO.sub.3. 4H.sub.2 O is isolated from aqueous solution. The catalyst is obtained from this compound by drying, calcination and subsequent reduction in a stream of hydrogen, whilst maintaining very specific temperature gradients between the drying stage and the calcination stage. A process for the manufacture of gases containing methane from hydrocarbons by steam cracking, in which the abovementioned catalyst is employed, is also described.