Industrial process for production of high-purity diphenyl carbonate

1. A process for the production of a high-purity diphenyl carbonate, the process comprising the steps of:

(i) carrying out a transestrification reaction between a dialkyl carbonate and a phenol and/or a disproportionation reaction of an alkyl carbonate and/or a transesterification reaction between an alkyl phenyl carbonate and a phenol in the presence of a homogeneous catalyst, so as to form a reaction mixture containing a diphenyl carbonate;

(ii) carrying out separation by distillation in a high boiling point material separating column A into a column top component A T containing the diphenyl carbonate and a column bottom component A B containing the catalyst

(iii) carrying out separation by distillation of said column top component A T in a diphenyl carbonate purifying column B having a side cut outlet into a column top component B T , a side cut component B S and a column bottom component B B , said column top component A T introducing from the side cut outlet into the column B; wherein

(a) said high boiling point material separating column A comprises a continuous multi-stage distillation column having a length L A (cm), an inside diameter D A (cm), and an internal with a number of stages n A thereinside, wherein L A , D A , and n A satisfy the following formulae (1) to (3);

800≦L A ≦3000  (1)

100≦D A ≦1000  (2)

20≦n A ≦100  (3);

(b) said diphenyl carbonate purifying column B comprises a continuous multi-stage distillation column having a length L B (cm), an inside diameter D B (cm), an internal thereinside, an inlet B 1 at a middle portion of the column, and a side cut outlet B 2 between said inlet B 1 and the column bottom, in which a number of stages of the internal above the inlet B 1 is n 1 , a number of stages n 2 of the internal between the inlet B 1 and the side cut outlet B 2 is n 2 , a number of stages n 3 of the internals below the side cut outlet B 2 is n 3 , and a total number of stages is n B (=n 1 +n 2 +n 3 ), wherein L B , D B , n 1 , n 2 , n 3 , and n B satisfy the following formulae (4) to (9);

1000≦L B ≦5000  (4)

100≦D B ≦1000  (5)

5≦n 1 ≦20  (6)

12≦n 2 ≦40  (7)

3≦n 3 ≦15  (8)

20≦n B ≦70  (9).

2. The process according to claim 1 , wherein not less than 1 ton/hr of the high-purity diphenyl carbonate is obtained as the side cut component B S .

3. The process according to claim 1 or 2 , wherein L A , D A , and n A for said high boiling point material separating column A satisfy the following formulae: 1000≦L A ≦2500, 200≦D A ≦600, and 30≦n A ≦70, respectively,

L B , D B , n 1 , n 2 , n 3 , and n B for said diphenyl carbonate purifying column B satisfy the following formulae: 1500≦L B ≦3000, 150≦D B ≦500, 7≦n 1 ≦15, 12≦n 2 ≦30, 3≦n 3 ≦10, and 25≦n B ≦55, respectively,

T A is in a range of from 190 to 240° C., P A is in a range of from 2000 to 15000 Pa,

T B is in a range of from 190 to 240° C., and P B is in a range of from 2000 to 15000 Pa.

4. The process according to claim 1 , wherein each of said high boiling point material separating column A and said diphenyl carbonate purifying column B is a distillation column having a tray and/or a packing as said internal.

5. The process according to claim 4 , wherein said internal of each of said high boiling point material separating column A and said diphenyl carbonate purifying column B is a packing.

6. The process according to claim 5 , wherein said packing is structured packing.