Hydrogenation process
View Patent ↗The present invention provides an improved hydrogenation processes wherein heat is efficiently managed so that catalyst productivity is optimized. More particularly, in the processes of the present invention, a nonaqueous solvent is added to a reactant to provide a nonaqueous solvent/reactant mixture that can act as a heat sink and absorb at least a portion of the heat generated within the reactor. Desirably, a reaction product, or a solvent with a minimal number of hydroxyl groups, is utilized so that the formation of unwanted byproducts can be minimized.
1. A hydrogenation process comprising:
(a) combining a reactant with a nonaqueous solvent to form a nonaqueous solvent/reactant mixture;
(b) contacting the nonaqueous solvent/reactant mixture with hydrogen in the presence of a copper aluminum catalyst within an adiabatic reactor to form a reaction product; and
(c) removing at least a portion of any water present in the reaction product with a water removal process driven at least in part by the heat of reaction of the hydrogenation reaction.
2. The process of claim 1 , wherein the reactant is glycerin and the reaction product preferentially comprises propylene glycol.
3. The process of claim 1 , wherein the nonaqueous solvent comprises a solvent with a hydroxyl wt % of less than about 45 and a hydroxyl weight equivalent of greater than about 30.
4. The process of claim 3 , wherein the nonaqueous solvent comprises the reaction product and the glycerin is crude glycerin.
5. The process of claim 2 , wherein the glycerin is crude glycerol.
6. A glycerin hydrogenation process comprising:
(a) combining a glycerin feedstock with a nonaqueous solvent to provide a nonaqueous solvent/glycerin mixture having less than about 5 weight percent water; and
(b) contacting the nonaqueous solvent/glycerin mixture with hydrogen in the presence of a catalyst within an adiabatic reactor to preferentially form a propylene glycol reaction product comprising less than about 17 wt % water.
7. The process of claim 6 , wherein the propylene glycol reaction product comprises less than about 6 weight percent water.
8. The process of claim 6 , wherein the nonaqueous solvent comprises a solvent with a hydroxyl wt % of less than about 45 and a hydroxyl weight equivalent of greater than about 30.
9. The process of claim 6 , nonaqueous solvent comprises a reaction product, and prior to the contacting step, the reaction product/glycerin mixture is subjected to a distillation step.
10. The process of claim 9 , wherein the product of the distillation step is subjected to a flash evaporator/condensing step prior to the contacting step.