Abstract: A method for recovering dimethyl naphthalene-2,6-dicarboxylate (DMN) from a mixture of dimethyl naphthalene-2,6-dicarboxylate (DMN) and dimethyl terephthalate (DMT), which comprises recrystallizing said mixture in a mixed medium of ethylene glycol and methanol, said mixed medium containing 10 to 60% by weight of ethylene glycol, and separating precipitated dimethyl naphthalene-2,6-dicarboxylate (DMN). According to this invention, DMN can be recovered with high yield from a mixture of DMN and DMT which is obtained from depolymerization of a mixed polymer of polyethylene-2,6-naphthalenedicarboxylate and polyethylene terephthalate.

Abstract: A method for preparing a dialkylnaphthalene in one step by contacting an dialkylbenzene compound with a solid catalyst in a gas or liquid phase in the presence of hydrogen, using a catalyst having composition (I) or (II) below:(1)(M.sup.1).sub.a.(M.sup.2).sub.b.(SiO.sub.2.XAl.sub.2 O.sub.3).(Al.sub.2 O.sub.3).sub.c (I)(2) Mixture of II-(i) and II-(ii):(M.sup.3).sub.d.(Al.sub.2 O.sub.3) II-(i)(M.sup.4).sub.e.(SiO.sub.2.XAl.sub.2 O.sub.3) II-(ii)wherein M.sup.1 is a metal selected from the group consisting of metals belonging to group VIII of a periodic table and rhenium;M.sup.2 is a member selected from the group consisting of zinc, gallium, and oxides thereof;M.sup.3 is a metal belonging to group VIII of a periodic table;M.sup.4 is at least one alkali metal; anda, b, c, d, e, and X represent proportions, respectively.

Abstract: In a process for producing an alkenylbenzene by the reaction of an alkylbenzene having 8 or more carbon atoms and a conjugated diolefin, the improvement in which the reaction is performed in the presence of a catalyst obtained by dispersing (a) an alkali metal and (b) potassium carbonate and/or potassium hydroxide in the presence of (c) an aromatic hydrocarbon having at least a substituent with a double bond.

Abstract: A process for producing a crystalline aluminosilicate zeolite characterized by having (a) a silica/alumina mole ratio of from 10 to 100, (b) X-ray lattice distances d shown in Table A of the specification, and (c) a specific n-hexane adsorption, under limited measuring conditions, of at least 0.07 g/g, which comprises maintaining a silica source, an alumina source, and a zeolite selected from zeolites ZSM-5 and zeolites having said characteristics, in an aqueous solution containing 1 to 200 millimoles, per gram of said zeolite, of an alkali metal hydroxide under such temperature, pressure and time conditions as to produce a crystalline aluminosilicate zeolite; and a crystalline aluminosilicate zeolite characterized by having aforesaid properties (a) to (c) and (d) a (2-methylpentane/cyclohexane) adsorption ratio of from 1.1 to 1.6.

Abstract: A process for continuously isomerizing xylene, which comprises subjecting a hydrocarbon feed material comprising a major proportion of a xylene isomer mixture and a minor proportion of non-aromatic hydrocarbons to xylene isomerization reaction, isolating a specific xylene isomer from the resulting isomerization reaction mixture, and recycling the remaining hydrocarbon mixture to the xylene isomerization reaction; wherein the hydrocarbon feed material or the xylene isomerization reaction mixture is treated with hydrogen in the presence of a cracking catalyst comprising(a) a zeolite selected from zeolites ZSM-5, ZSM-11, ZSM-12, ZSM-34 and ZSM-48 series, at least 20% of its cation site being occupied by a cation of a metal selected from alkali metals and alkaline earth metals, and(b) a refractory amorphous inorganic oxide having platinum supported thereon,at a temperature and a weight hourly space velocity which simultaneously satisfy the following inequalities (i) to (iv) ##EQU1## wherein T represents the tempe

Abstract: A novel crystalline aluminosilicate zeolite characterized by having a composition of the following general formula expressed in terms of the mole ratios of oxides in the anhydrous statexM.sub.2/n O.Al.sub.2 O.sub.3.ySiO.sub.2wherein M represents at least one cation having a valence of n, x is a number between 0.5 and 4, and y is a number of at least 10, and having a specific X-ray diffraction pattern. Said crystalline aluminosilicate zeolite can be produced by maintaining a mixture of a water-soluble alkali metal compound, an N,N,N,N',N',N'-hexamethyl-1,6-hexane diammonium compound, a compound capable of giving silica under the reaction conditions, a compound capable of giving alumina under the reaction conditions and water, at a temperature of at least 80.degree. C. for a period sufficient to form crystals, and is useful as a catalyst for, for example, transalkylation or alkylation reaction of toluene, isomerization of xylene, isomerization of ethylbenzene to xylenes, etc.

Abstract: A process for producing a crystalline zeolite TPZ-12, which comprises maintaining a starting mixture at a temperature of at least 80.degree. C. for a period sufficient to produce zeolite crystals, said starting mixture consisting of(a) a substance capable of yielding silica under the reaction conditions,(b) a water-soluble alkali metal compound,(c) water, and(d) a diammonium compound represented by the following general formula ##STR1## wherein R.sub.1 and R.sub.2 are identical or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, p and q are identical or different and each represents an integer of 4 or 5, n is 4, 5 or 6, and y represents an anion having a valence of m, and additionally, if desired,(e) a substance capable of yielding alumina under the reaction conditions,in the particular quantities.

Abstract: A novel crystalline aluminosilicate zeolite characterized by having(a) a silica/alumina mole ratio in the range of from 10 to 100,(b) X-ray lattice distances d shown in Table A in the specification, and(c) a (cyclohexane/n-hexane) adsorption ratio of at least 0.7. This crystalline aluminosilicate zeolite is useful, for example, as a catalyst in the isomerization reaction or transalkylation reaction of alkylbenzenes or alkylnaphthalenes, and can be prepared by heating a crystalline aluminosilicate zeolite ZSM-5 having a silica/alumina mole ratio of from 20 to 300 at a temperature between 80.degree. C. and 250.degree. C. in an aqueous solution containing 0.1 to 1 g, per gram of the ZSM-5 zeolite, of an alkali metal hydroxide.

Abstract: A catalyst composition comprising (i) a crystalline aluminosilicate selected from the group consisting of zeolite ZSM-5, zeolite ZSM-11, zeolite ZSM-12, zeolite ZSM-35 and zeolite ZSM-38 and having a silica/alumina mole ratio of 20 to 1,000; and (ii) at least two metals which are (a) platinum and (b) at least one other metal selected from the group consisting of titanium, chromium, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, palladium, tin, barium, cerium, tungsten, osmium, lead, cadmium, mercury, indium, lanthanum and beryllium. This catalyst composition is useful particularly for the isomerization of aromatic hydrocarbons and reforming of naphtha.

Abstract: In a process for producing p-xylene which comprises catalytically methylating toluene with a methylating agent in the gaseous phase, the improvement wherein(a) said methylation is carried out continuously in a multi-stage reaction system consisting of a plurality of separate series-connected fixed catalyst layers without separating the resulting xylenes in an intermediate stage,(b) said toluene is fed together with hydrogen gas into only the first-stage fixed catalyst layer and passed successively through the subsequent fixed catalyst layers, the amount of toluene fed being such that the total weight hourly space velocity of toluene is from 1 to 300 hr.sup.-1,(c) said methylating agent is fed into each of said fixed catalyst layers, if desired together with hydrogen gas, the amount of the methylating agent fed into each catalyst layer being 0.

Abstract: In a process for isomerization of xylenes which comprises contactng an aromatic hydrocarbon stock mainly containing xylene isomers not attaining a thermodynamic equilibrium composition with a catalyst composition containing a crystalline aluminosilicate at an elevated temperature in the vapor phase in the presence of hydrogen, the improvement wherein said catalyst composition comprises a crystalline aluminosilicate having a silica/alumina mole ratio of at least 10 and contains at least two metals which are (a) platinum and (b) at least one metal selected from the group consisting of titanium, chromium, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, palladium, tin, barium, cesium, cerium, tungsten, osmium, lead, cadmium, mercury, indium, lanthanum, beryllium, lithium and rubidium.

Abstract: In a process for dealkylating a hydrocarbon material containing at least one alkyl-substituted aromatic hydrocarbon having bonded to the aromatic ring at least one alkyl group with at least 2 carbon atoms in the gaseous phase in the presence of hydrogen using a hydro-dealkylation catalyst, the improvement wherein (a) said hydro-dealkylation catalyst is composed of a crystalline aluminosilicate having a silica/alumina mole ratio of from 20 to 200 and containing a noble metal selected from platinum, palladium, rhodium and iridium, and (b) said dealkylation is carried out at a temperature of 250.degree. C. to 420.degree. C. and a pressure of not more than 100 psig, thereby selectively removing said alkyl group containing at least 2 carbon atoms from said alkyl-substituted aromatic hydrocarbon.