The invention relates to a method for producing styrene monomers by the depolymerisation of polystyrene in the presence of foreign polymers, such as polyolefins. Said method comprises the following steps: a) introducing a polymer composition (A) containing: I) 10 to 99.5% by weight, based on the polymer composition (A), of polystyrene (I); and II) 0.1 to 89.9% by weight of polyolefin (II); and/or III) 0.1 to 4.9% by weight of acrylonitrile-based polymer (III); and/or IV) 0.1 to 4.9% by weight of polyester (IV), into the reaction zone (R) of a pyrolysis reactor (P); b) thermal cracking the polystyrene contained in the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) at a temperature of between 400-1000° C., c) removing the product mixture (G) obtained from the reaction zone (R), d) cooling of the product mixture (G), and e) separating the styrene monomers from the further components.

The invention relates to a method for producing styrene monomers by the depolymerisation of polystyrene in the presence of foreign polymers, such as polyolefins. Said method comprises the following steps: a) introducing a polymer composition (A) containing: I) 10 to 99.5% by weight, based on the polymer composition (A), of polystyrene (I); and II) 0.1 to 89.9% by weight of polyolefin (II); and/or III) 0.1 to 4.9% by weight of acrylonitrile-based polymer (III); and/or IV) 0.1 to 4.9% by weight of polyester (IV), into the reaction zone (R) of a pyrolysis reactor (P); b) thermal cracking the polystyrene contained in the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) at a temperature of between 400-1000° C., c) removing the product mixture (G) obtained from the reaction zone (R), d) cooling of the product mixture (G), and e) separating the styrene monomers from the further components.

According to one or more embodiments, a method for forming light olefins may comprise introducing a hydrocarbon feed stream into a reactor, reacting the hydrocarbon feed stream with a dehydrogenation catalyst in the reactor to form a high temperature dehydrogenated product, separating at least a portion of the dehydrogenation catalyst from the high temperature dehydrogenated product in a primary separation device, combining the high temperature dehydrogenation product with a quench stream to cool the high temperature dehydrogenation product and form an intermediate temperature dehydrogenation product, and cooling the intermediate temperature dehydrogenation product to form a cooled dehydrogenation product.

According to one or more embodiments, a method for forming light olefins may comprise introducing a hydrocarbon feed stream into a reactor, reacting the hydrocarbon feed stream with a dehydrogenation catalyst in the reactor to form a high temperature dehydrogenated product, separating at least a portion of the dehydrogenation catalyst from the high temperature dehydrogenated product in a primary separation device, combining the high temperature dehydrogenation product with a quench stream to cool the high temperature dehydrogenation product and form an intermediate temperature dehydrogenation product, and cooling the intermediate temperature dehydrogenation product to form a cooled dehydrogenation product.

A method for preparing alpha-methylstyrene according to one embodiment of the present disclosure includes dehydrating a dimethylbenzyl alcohol solution in a reactor under an acid catalyst to prepare alpha-methylstyrene, where a reaction product after the dehydration reaction comprises a first reaction product including a first alpha-methylstyrene; and a second reaction product including vapor (H.sub.2O), a second alpha-methylstyrene and unreacted materials; and separating the second alpha-methylstyrene and the unreacted materials comprised in the second reaction product and recirculating the second alpha-methylstyrene and the unreacted materials to the reactor, a temperature inside the reactor during the dehydration reaction is 135° C. or higher, and a content of the acid catalyst is from 100 ppm to 1,500 ppm based on a total weight of dimethylbenzyl alcohol of the dimethylbenzyl alcohol solution.

A method for preparing alpha-methylstyrene according to one embodiment of the present disclosure includes dehydrating a dimethylbenzyl alcohol solution in a reactor under an acid catalyst to prepare alpha-methylstyrene, where a reaction product after the dehydration reaction comprises a first reaction product including a first alpha-methylstyrene; and a second reaction product including vapor (H.sub.2O), a second alpha-methylstyrene and unreacted materials; and separating the second alpha-methylstyrene and the unreacted materials comprised in the second reaction product and recirculating the second alpha-methylstyrene and the unreacted materials to the reactor, a temperature inside the reactor during the dehydration reaction is 135° C. or higher, and a content of the acid catalyst is from 100 ppm to 1,500 ppm based on a total weight of dimethylbenzyl alcohol of the dimethylbenzyl alcohol solution.

The present invention provides a process of catalytic depolymerization of polystyrene involving a spherical catalyst, an apparatus for carrying out the depolymerization, recovering the aromatic rich liquid product and recycling the catalyst without any decrease in the catalytic performance. Further, the present invention provides that the aromatic rich liquid product includes styrene, xylene, benzene, ethyl benzene, with styrene content greater than 65%. Additionally, the catalyst involved in the depolymerization process is a spherical catalyst that is easily recovered from coke/char formed during the process and is recycled and reused without any decrease in the catalytic performance.

The present invention provides a process of catalytic depolymerization of polystyrene involving a spherical catalyst, an apparatus for carrying out the depolymerization, recovering the aromatic rich liquid product and recycling the catalyst without any decrease in the catalytic performance. Further, the present invention provides that the aromatic rich liquid product includes styrene, xylene, benzene, ethyl benzene, with styrene content greater than 65%. Additionally, the catalyst involved in the depolymerization process is a spherical catalyst that is easily recovered from coke/char formed during the process and is recycled and reused without any decrease in the catalytic performance.

The disclosure relates to a zeolite catalyst for side-chain alkylation of toluene with methanol, including a zeolite NaX and Na.sub.3PO.sub.4 or Na.sub.2HPO.sub.4 supported on the zeolite NaX. The zeolite catalyst can be effective for catalyzing the side-chain alkylation of toluene with methanol. The disclosure also relates to a process for preparing a zeolite catalyst for side-chain alkylation of toluene with methanol, which is simple, practical and cheap in cost.

The disclosure relates to a zeolite catalyst for side-chain alkylation of toluene with methanol, including a zeolite NaX and Na.sub.3PO.sub.4 or Na.sub.2HPO.sub.4 supported on the zeolite NaX. The zeolite catalyst can be effective for catalyzing the side-chain alkylation of toluene with methanol. The disclosure also relates to a process for preparing a zeolite catalyst for side-chain alkylation of toluene with methanol, which is simple, practical and cheap in cost.