Solid acid catalyst and method for preparing and using the same
A solid acid catalyst having a strong acid cation exchange resin having a cross-linking network structure and free aromatic sulfonic acids adsorbed in the network. The solid acid catalyst is prepared by treating a strong acid cation exchange resin with aromatic sulfonic acids in a solution. The catalyst is useful for synthesizing rubber antioxidant RD and other strong-acid catalyzed reactions.
1. A solid acid catalyst consisting essentially of a strong acid cation exchange resin having a cross-linking network, and free aromatic sulfonic acids adsorbed in the cross-linking network of the strong acid cation exchange resin, wherein the free aromatic sulfonic acids are about 0.01 to 3% by weight of total weight of the catalyst.
2. The solid acid catalyst according to claim 1 , wherein the strong acid cation exchange resin is based on styrene, acrylic acid ester, or both, is cross-linked by divinyl benzene, and bears sulfonic groups.
3. The solid acid catalyst according to claim 2 , wherein the strong acid cation exchange resin is selected from the group consisting Cation Exchange Resin, 732, Cation Exchange Resin 734, Cation Exchange DH, Cation Exchange Resin D001, Cation Exchange Resin D002, Cation Exchange Resin D061, Cation Exchange Resin, D072, Cation Exchange Resin JK008, and a mixture thereof.
4. The solid acid catalyst according to claim 1 , wherein the aromatic sulfonic acids are selected from the group consisting of benzene sulfonic acid, a monoalkyl benzene sulfonic acids, a dialkyl benzene sulfonic acids, a multi-alkyl benzene sulfonic acid, a halo-benzene sulfonic acid, an optionally substituted benzene disulfonic acid, an optionally substituted trisulfonic acid, and a mixture thereof.
5. The solid acid catalyst according to claim 4 , wherein the aromatic sulfonic acid is selected from the group consisting of benzene sulfonic acid, p-toluene sulfonic acid, o-toluene sulfonic acid, m-toluene sulfonic acid, p-ethyl benzene sulfonic acid, dimethyl benzene sulfonic acid, p-fluoro-benzene sulfonic acid, o-fluoro-benzene sulfonic acid, m-fluoro-benzene sulfonic acid, p-chloro-benzene sulfonic acid, o-chloro-benzene sulfonic acid, m-chloro-benzene sulfonic acid, p-benzene disulfonic acid, o-benzene disulfonic acid, m-benzene disulfonic acid, and a mixture thereof.
6. The solid acid catalyst according to claim 1 , wherein the solid acid catalyst is a compound of Cation Exchange Resin D002 and p-toluene sulfonic acid.
7. The solid acid catalyst according to claim 6 , wherein weight ratio of Cation Exchange Resin D002 to p-toluene sulfonic acid is about 1: 0.001to 1: 0.5.
8. The solid acid catalyst according to claim 7 , wherein the weight ratio of Cation Exchange Resin D002 to p-toluene sulfonic acid is about 1: 0.01 to 1: 0.2.
9. A process for preparing the solid acid catalyst of claim 1 , comprising
adding the strong acid cation exchange resin in a hydrochloric acid solution of an aromatic sulfonic acid,
stirring the strong acid cation exchange resin in the hydrochloric acid solution to form a mixture,
letting the mixture stand for a period of time,
isolating solid material from the mixture, and
drying the solid material to obtain the solid acid catalyst of claim 1 .
10. The process according to claim 9 , wherein concentration of hydrochloric acid in the solution is about 0.01-10% by weight.
11. The process according to claim 10 , wherein the concentration of hydrochloric acid in the solution is about 0.1-7% by weight.
12. The process according to claim 11 , wherein the concentration of hydrochloric acid in the solution is about 1-5% by weight.