A fluidized-bed catalyst suitable for the production of halogenated aromatic nitriles includes an active component and a support. The active component is a complex having the following composition expressed in atomic ratio:

VP.sub.aCr.sub.bA.sub.cM.sub.dO.sub.x, wherein A represents at least one metal selected from the group consisting of alkali metals and alkaline earth metals; M represents at least one element selected from the group consisting of Ti, Zr, Hf, La, Ce, Nb, Mo, W, Co, Zn, Fe, Ni, B, Sb, Bi, As, Ga, Ge, Sn, and In; in the XRD spectrum of the catalyst, diffraction peaks are present at 2=27.80.5 and 2=13.80.5, and the ratio of the height (I.sub.1) of the diffraction peak at 2=27.80.5 to the height (I.sub.2) of the diffraction peak at 2=13.80.5 is 3.5-6, i.e. I.sub.1:I.sub.2=3.5-6.

A process provides for minimizing an amount of fuel gas utilized in an absorber off-gas incinerator and better control of emissions. The process provides for less temperature deviations in the absorber off-gas incinerator firebox and for less deviation in an amount of oxygen in the absorber off-gas incinerator stack gas.

A process provides for minimizing an amount of fuel gas utilized in an absorber off-gas incinerator and better control of emissions. The process provides for less temperature deviations in the absorber off-gas incinerator firebox and for less deviation in an amount of oxygen in the absorber off-gas incinerator stack gas.

The present invention can provide a method for producing an aromatic nitrile in which a fixed-bed reactor including a plurality of reaction tubes is used to subject a gaseous mixture comprising an aromatic hydrocarbon, ammonia, and oxygen by contact catalytic reaction on a catalyst to thereby produce the corresponding aromatic nitrile, wherein the catalyst is composed of an oxide containing vanadium, chromium, and boron and one or more supports selected from among alumina, silica-alumina, zirconia, and titania. One of the reaction tubes is filled with the catalyst of one kind and examined as to where a hot spot lies therein. An inert substance is filled into that portion of each of the plurality of reaction tubes which corresponds at least to the hot spot, and the catalyst is filled into the remaining portions.

The present invention can provide a method for producing an aromatic nitrile in which a fixed-bed reactor including a plurality of reaction tubes is used to subject a gaseous mixture comprising an aromatic hydrocarbon, ammonia, and oxygen by contact catalytic reaction on a catalyst to thereby produce the corresponding aromatic nitrile, wherein the catalyst is composed of an oxide containing vanadium, chromium, and boron and one or more supports selected from among alumina, silica-alumina, zirconia, and titania. One of the reaction tubes is filled with the catalyst of one kind and examined as to where a hot spot lies therein. An inert substance is filled into that portion of each of the plurality of reaction tubes which corresponds at least to the hot spot, and the catalyst is filled into the remaining portions.

The present invention can provide a method for producing an aromatic nitrile in which a fixed-bed reactor including a plurality of reaction tubes is used to subject a gaseous mixture comprising an aromatic hydrocarbon, ammonia, and oxygen by contact catalytic reaction on a catalyst to thereby produce the corresponding aromatic nitrile, wherein the catalyst is composed of an oxide containing vanadium, chromium, and boron and one or more supports selected from among alumina, silica-alumina, zirconia, and titania. One of the reaction tubes is filled with the catalyst of one kind and examined as to where a hot spot lies therein. An inert substance is filled into that portion of each of the plurality of reaction tubes which corresponds at least to the hot spot, and the catalyst is filled into the remaining portions.

The object is to prevent deterioration and loss of dicyanobenzene in producing dicyanobenzene by ammoxidation of xylene to thereby achieve industrial and economical advantage in producing of dicyanobenzene. The method for producing dicyanobenzene of the present invention includes: contacting a xylene-ammoxidation reaction gas containing dicyanobenzene in ammoxidation of xylene with an organic solvent so as to obtain a dicyanobenzene-absorbing solution; contacting the dicyanobenzene-absorbing solution with a basic aqueous solution containing a salt such as ammonium carbonate so as to extract a water-soluble salt formed by neutralization reaction between carboxylic acid in the dicyanobenzene-absorbing solution and a base in the basic aqueous solution into an aqueous phase; separating the mixture of the dicyanobenzene-absorbing solution and the basic aqueous solution into an organic phase and an aqueous phase; decomposing the salt such as ammonium carbonate contained in the organic phase for separation of the salt from the organic phase; and distilling the organic phase to separate low boiling point compounds contained in the organic phase from the organic phase so as to obtain dicyanobenzene.

The object is to prevent deterioration and loss of dicyanobenzene in producing dicyanobenzene by ammoxidation of xylene to thereby achieve industrial and economical advantage in producing of dicyanobenzene. The method for producing dicyanobenzene of the present invention includes: contacting a xylene-ammoxidation reaction gas containing dicyanobenzene in ammoxidation of xylene with an organic solvent so as to obtain a dicyanobenzene-absorbing solution; contacting the dicyanobenzene-absorbing solution with a basic aqueous solution containing a salt such as ammonium carbonate so as to extract a water-soluble salt formed by neutralization reaction between carboxylic acid in the dicyanobenzene-absorbing solution and a base in the basic aqueous solution into an aqueous phase; separating the mixture of the dicyanobenzene-absorbing solution and the basic aqueous solution into an organic phase and an aqueous phase; decomposing the salt such as ammonium carbonate contained in the organic phase for separation of the salt from the organic phase; and distilling the organic phase to separate low boiling point compounds contained in the organic phase from the organic phase so as to obtain dicyanobenzene.

A method for producing meta-xylylenediisocyanates includes a reaction step in which monohalogenated benzenes, formaldehydes, and an amide compound represented by general formula (1) below are allowed to react in the presence of an acidic liquid to produce a bisamide compound; a dehalogenation step in which in the bisamide compound, the halogen atom derived from the monohalogenated benzenes is replaced with a hydrogen atom; and a thermal decomposition step in which the bisamide compound from which the halogen atom is eliminated is subjected to thermal decomposition. In the reaction step, the acidic liquid contains inorganic acid, the equivalent ratio of the hydrogen atom of the inorganic acid relative to the monohalogenated benzenes is more than 14, the acidic liquid has an inorganic acid concentration of more than 90 mass %, and the reaction temperature is more than 10 C. General formula (1): ##STR00001##
wherein R.sup.1 represents an alkoxy group or an amino group.