Process for the preparation of toluylene diisocyanate, specific mixtures of toluylene diamine and water, and the use of toluylene diamine and water mixtures to prepare toluylene diisocyanate

In a process for preparing a toluenediamine product containing mainly 2,4- and 2,6-toluenediamine for storage and/or transportation in tanker containers which comprises the steps of effecting dinitration of toluene by the mixed acid method and producing a reaction product containing dinitrotoluene, hydrogenating the reaction product containing dinitrotoluene under conditions for forming a hydrogenated reaction product containing mainly 2,4- and 2,6-toluenediamine, distilling water and contaminants from the hydrogenated reaction product at elevated temperature, and recovering the resultant distillation product thereby generating a toluenediamine product for storage or shipment, the improvement which comprises:

• only partially removing the water in the hydrogenated reaction product during distillation;
• adjusting the water content in the distillation product containing mainly 2,4- and 2,6-toluenediamine in an amount of from 1 to 40% by weight of the distillation product thereby generating a liquid toluenediamine-water mixture;
• wherein the resultant toluenediamine-water mixture has a freezing point of at most 95° C.

In a process for producing a meta-toluene diamine mixture wherein toluene is contacted with nitric acid in the presence of sulfuric acid under conditions for producing a reaction product containing primarily a dinitrotoluene isomer mixture, the dinitrotoluene recovered and then contacted with hydrogen in the presence of a hydrogenation catalyst, the resulting reaction product containing 2,4- and 2,6-toluene diamine formed into a liquid toluene diamine mixture, distilled in a column at elevated temperature to remove any water, ortho-toluene diamine and by-products, the substantially anhydrous meta-toluene diamine isomer mixture recovered from the bottom of the column, the improvement for preparing the resulting meta-toluene diamine isomer mixture for storage and/or transport which comprises:

• partially removing the water in the liquid toluene diamine mixture during distillation,
• adjusting the water content in the liquid toluene diamine mixture, in an amount of from 1 to 40% by weight of the liquid toluene diamine mixture,
• such that the toluene diamine-water mixture has a freezing point of at most 95° C.

In a process for preparing a toluenediamine product containing mainly 2,4- and 2,6-toluenediamine for storage and/or transportation in tanker containers which comprises the steps of effecting dinitration of toluene by the mixed acid method and producing a reaction product containing dinitrotoluene, hydrogenating the reaction product containing dinitrotoluene under conditions for forming a hydrogenated reaction product containing predominantly 2,4- and 2,6-toluenediamine and water, the improvement which comprises:

• distilling said hydrogenated reaction product and only partially removing the water in said product during the distillation;
• adjusting the water content in the distillation product containing mainly 2,4- and 2,6-toluenediamine to an amount from 1 to 40% by weight of the distillation product thereby generating a liquid toluenediamine-water mixture, wherein the resultant toluenediamine-water mixture has a freezing point of at most 95° C.