Process for industrial production of an aromatic carbonate
It is an object of the present invention to provide a specific process that enables aromatic carbonates to be produced with high selectivity and high productivity stably for a prolonged period of time on an industrial scale of not less than 1 ton per hour from a dialkyl carbonate and an aromatic monohydroxy compound using two continuous multi-stage distillation columns. Although there have been various proposals regarding processes for the production of aromatic carbonates by means of a reactive distillation method, these have all been on a small scale and short operating time laboratory level, and there have been no disclosures whatsoever on a specific process or apparatus enabling mass production on an industrial scale. According to the present invention, there are provided two specified continuous multi-stage distillation columns, and there is also provided a specific process that enables aromatic carbonates to be produced with high selectivity and high productivity stably for a prolonged period of time on an industrial scale of not less than 1 ton per hour from a dialkyl carbonate and an aromatic monohydroxy compound using a apparatus in which these two continuous multi-stage distillation columns are connected together.
1. A process for the production of an aromatic carbonate containing a diaryl carbonate as a main product from a dialkyl carbonate and an aromatic monohydroxy compound as a starting material, which comprises the steps of:
(i) continuously feeding said starting material into a first continuous multi-stage distillation column in which a catalyst is present;
(ii) carrying out the reaction in said first column to produce an alcohol and an alkyl aryl carbonate;
(iii) continuously withdrawing a first column low boiling point reaction mixture containing a produced alcohol from an upper portion of said first column in a gaseous form while continuously withdrawing a first column high boiling point reaction mixture containing an alkyl aryl carbonate from a lower portion of said first column in a liquid form;
(iv) continuously feeding said first column high boiling point reaction mixture into a second continuous multi-stage distillation column in which a catalyst is present and which is connected to said first column while carrying out the reaction in said second column to produce a dialkyl carbonate and a diaryl carbonate;
(v) continuously withdrawing a second column low boiling point reaction mixture containing said produced dialkyl carbonate from an upper portion of said second column in a gaseous form while continuously withdrawing a second column high boiling point reaction mixture containing said produced diaryl carbonate from a lower portion of said second column in a liquid form; wherein
(a) a molar ratio of the dialkyl carbonate to the aromatic monohydroxy compound in said starting material which is fed continuously into said first continuous multi-stage distillation column is in a range of from 0.1 to 10;
(b) said first continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 1 (cm) and an inside diameter D 1 (cm), and having an internal with a number of stages n 1 thereinside, and has a gas outlet having an inside diameter d 11 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 12 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 1 (cm) satisfies the following formula (1),
1500≦L 1 ≦8000 (1),
(2) said inside diameter D 1 (cm) of the column satisfies the following formula (2),
100≦D 1 ≦2000 (2),
(3) a ratio of said length L 1 (cm) to said inside diameter D 1 (cm) of the column satisfies the following formula (3),
2 ≦L 1 /D 1 ≦40 (3),
(4) said number of stages n 1 satisfies the following formula (4),
20≦n 1 ≦120 (4),
(5) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 11 (cm) of the gas outlet satisfies the following formula (5),
5 ≦D 1 /d 11 ≦30 (5), and
(6) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 12 (cm) of the liquid outlet satisfies the following formula (6),
3 ≦D 1 /d 12 ≦20 (6);
(c) said second continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 2 (cm) and an inside diameter D 2 (cm), and having an internal with a number of stages n 2 thereinside, and has a gas outlet having an inside diameter d 21 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 22 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 2 (cm) satisfies the following formula (7),
1500≦L 2 ≦8000 (7),
(2) said inside diameter D 2 (cm) of the column satisfies the following formula (8),
100≦D 2 ≦2000 (8),
(3) a ratio of the length L 2 (cm) to said inside diameter D 2 (cm) of the column satisfies the following formula (9),
2 ≦L 2 /D 2 ≦40 (9),
(4) said number of stages n 2 satisfies the following formula (10),
10≦n 2 ≦80 (10),
(5) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 21 (cm) of the gas outlet satisfies the following formula (11),
2 ≦D 2 /d 21 ≦15 (11), and
(6) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 22 (cm) of the liquid outlet satisfies the following formula (12),
5 ≦D 2 /d 22 ≦30 (12).
2. The process according to claim 1 , wherein distillation is carried out simultaneously in said step (ii) and said step (iv).
3. The process according to claim 1 , wherein an amount of said diaryl carbonate produced is not less than 1 ton per hour.
4. In a process for the production of an aromatic carbonate containing a diaryl carbonate as a main product in which the aromatic carbonate containing the diaryl carbonate as the main product are produced continuously by taking a mixture of a dialkyl carbonate and an aromatic monohydroxy compound as a starting material, continuously feeding the starting material into a first continuous multi-stage distillation column in which a catalyst is present, carrying out the reaction and the distillation simultaneously said the first column, continuously withdrawing a first column low boiling point reaction mixture containing a produced alcohol from an upper portion of said first column in a gaseous form, continuously withdrawing a first column high boiling point reaction mixture containing a produced alkyl aryl carbonate from a lower portion of said first column in a liquid form, continuously feeding the first column high boiling point reaction mixture into a second continuous multi-stage distillation column in which a catalyst is present, carrying out the reaction and the distillation simultaneously in said second column, continuously withdrawing a second column low boiling point reaction mixture containing a produced dialkyl carbonate from an upper portion of said second column in a gaseous form, continuously withdrawing a second column high boiling point reaction mixture containing a produced diaryl carbonate from a lower portion of said second column in a liquid form while continuously feeding the second column low boiling point reaction mixture containing the dialkyl carbonate into the first continuous multi-stage distillation column, the improvement in which:
(a) a molar ratio of the dialkyl carbonate to the aromatic monohydroxy compound in said starting material which is fed continuously into said first continuous multi-stage distillation column is in a range of from 0.1 to 10;
(b) said first continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 1 (cm) and an inside diameter D 1 (cm), and having an internal with a number of stages n 1 thereinside, and has a gas outlet having an inside diameter d 11 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 12 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 1 (cm) satisfies the following formula (1),
1500≦L 1 ≦8000 (1),
(2) said inside diameter D 1 (cm) of the column satisfies the following formula (2),
100≦D 1 ≦2000 (2),
(3) a ratio of said length L 1 (cm) to said inside diameter D 1 (cm) of the column satisfies the following formula (3),
2 ≦L 1 /D 1 ≦40 (3),
(4) said number of stages n 1 satisfies the following formula (4),
20≦n 1 ≦120 (4),
(5) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 11 (cm) of the gas outlet satisfies the following formula (5),
5 ≦D 1 /d 11 ≦30 (5), and
(6) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 12 (cm) of the liquid outlet satisfies the following formula (6),
3 ≦D 1 /d 12 ≦20 (6);
(c) said second continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 2 (cm) and an inside diameter D 2 (cm), and having an internal with a number of stages n 2 thereinside, and has a gas outlet having an inside diameter d 21 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 22 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 2 (cm) satisfies the following formula (7),
1500≦L 2 ≦8000 (7),
(2) said inside diameter D 2 (cm) of the column satisfies the following formula (8),
100≦D 2 ≦2000 (8),
(3) a ratio of the length L 2 (cm) to said inside diameter D 2 (cm) of the column satisfies the following formula (9),
2 ≦L 2 /D 2 ≦40 (9),
(4) said number of stages n 2 satisfies the following formula (10),
10≦n 2 ≦80 (10),
(5) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 21 (cm) of the gas outlet satisfies the following formula (11),
2 ≦D 2 /d 21 ≦15 (11), and
(6) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 22 (cm) of the liquid outlet satisfies the following formula (12),
5 ≦D 2 /d 22 ≦30 (12).
5. The process according to claim 4 , wherein an amount produced of the diaryl carbonate is not less than 1 ton per hour.
6. The process according to claim 1 , wherein d 11 and d 12 satisfy the following formula (13), and d 21 and d 22 satisfy the following formula (14)
1 ≦d 12 /d 11 ≦5 (13)
1 ≦d 21 /d 22 ≦6 (14).
7. The process according to claim 1 , wherein L 1 , D 1 , L 1 /D 1 , n 1 , D 1 /d 11 , and D 1 /d 12 for said first continuous multi-stage distillation column satisfy the following formulae: 2000≦L 1 ≦6000, 150≦D 1 ≦1000, 3≦L 1 /D 1 ≦30, 30≦n 1 ≦100, 8≦D 1 /d 11 ≦25, and 5≦D 1 /d 12 ≦18, respectively, and
L 2 , D 2 , L 2 /D 2 , n 2 , D 2 /d 21 , and D 2 /d 22 for said second continuous multi-stage distillation column satisfy the following formulae: 2000≦L 2 ≦6000, 150≦D 2 ≦1000, 3≦L 2 /D 2 ≦30, 15≦n 2 ≦60, 2.5≦D 2 /d 21 ≦12, and 7≦D 2 /d 22 ≦25, respectively.
8. The process according to claim 1 , wherein, L 1 , D 1 , L 1 /D 1 , n 1 , D 1 /d 11 , and D 1 /d 12 for said first continuous multi-stage distillation column satisfy the following formulae: 2500≦L 1 ≦5000, 200≦D 1 ≦800, 5≦L 1 /D 1 ≦15, 40≦n 1 ≦90, 10≦D 1 /d 11 ≦25, and 7≦D 1 /d 12 ≦15, respectively, and
L 2 , D 2 , L 2 /D 2 , n 2 , D 2 /d 21 , and D 2 /d 22 for said second continuous multi-stage distillation column satisfy the following formulae: 2500≦L 2 ≦5000, 200≦D 2 ≦800, 5≦L 2 /D 2 ≦15, 20≦n 2 ≦50, 3≦D 2 /d 21 ≦10, and 9≦D 2 /d 22 ≦20, respectively.
9. The process according to claim 1 , wherein each of said first continuous multi-stage distillation column and said second continuous multi-stage distillation column is a distillation column having a tray and/or a packing as the internal.
10. The process according to claim 9 , wherein said first continuous multi-stage distillation column is a plate-type distillation column having the tray as the internal, and said second continuous multi-stage distillation column is a distillation column having both the packing and the tray as the internal.
11. The process according to claim 9 , wherein each of the trays in said first continuous multi-stage distillation column and said second continuous multi-stage distillation column is a sieve tray having a sieve portion and a down corner portion.
12. The process according to claim 11 , wherein said sieve tray has 100 to 1000 holes/m 2 in the sieve portion.
13. The process according to claim 11 , wherein the cross-sectional area per hole of said sieve tray is in a range of from 0.5 to 5 cm 2 .
14. The process according to claim 9 , wherein said second continuous multi-stage distillation column is a distillation column having, as said internal, the packing in an upper portion of the column, and the tray in a lower portion of the column.
15. The process according to claim 1 , wherein said packing of said internal in said second continuous multi-stage distillation column is one or more of a structured packing.
16. The process according to claim 15 , wherein said structured packing in said second continuous multi-stage distillation column is of at least one selected from the group consisting of Mellapak, Gempak, TECHNO-PAK, FLEXI-PAK, a Sulzer packing, a Goodroll packing and a Glitchgrid.
17. The process according to claim 1 , wherein said first continuous multi-stage distillation column comprises two or more of distillation columns.
18. The process according to claim 1 , wherein said second continuous multi-stage distillation column comprises two or more of distillation columns.
19. An aromatic carbonate comprising a halogen content of not more than 0.1 ppm, produced by the process according to claim 1 .
20. A reactive distillation apparatus comprising a first continuous multi-stage distillation column for carrying out reaction and distillation; and a second continuous multi-stage distillation column for carrying out reaction and distillation, which is connected to said first continuous multi-stage distillation column, comprising:
(a) said first continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 1 (cm) and an inside diameter D 1 (cm), and having an internal with a number of stages n 1 thereinside, and has a gas outlet having an inside diameter d 11 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 12 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 1 (cm) satisfies the following formula (1),
1500≦L 1 ≦8000 (1),
(2) said inside diameter D 1 (cm) of the column satisfies the following formula (2),
100≦D 1 ≦2000 (2),
(3) a ratio of said length L 1 (cm) to said inside diameter D 1 (cm) of the column satisfies the following formula (3),
2 ≦L 1 /D 1 ≦40 (3),ps
(4) said number of stages n 1 satisfies the following formula (4),
20≦n 1 ≦120 (4),
(5) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 11 (cm) of the gas outlet satisfies the following formula (5),
5 ≦D 1 /d 11 ≦30 (5), and
(6) a ratio of said inside diameter D 1 (cm) of the column to said inside diameter d 12 (cm) of the liquid outlet satisfies the following formula (6),
3 ≦D 1 /d 12 ≦20 (6);
(b) said second continuous multi-stage distillation column comprises a structure having a pair of end plates above and below a cylindrical trunk portion having a length L 2 (cm) and an inside diameter D 2 (cm), and having an internal with a number of stages n 2 thereinside, and has a gas outlet having an inside diameter d 21 (cm) at the top of the column or in an upper portion of the column near to the top, a liquid outlet having an inside diameter d 22 (cm) at the bottom of the column or in a lower portion of the column near to the bottom, at least one inlet provided in the upper portion and/or a middle portion of the column below the gas outlet, and at least one inlet provided in the lower portion of the column above the liquid outlet, wherein
(1) said length L 2 (cm) satisfies the following formula (7),
1500≦L 2 ≦8000 (7),
(2) said inside diameter D 2 (cm) of the column satisfies the following formula (8),
100≦D 2 ≦2000 (8),
(3) a ratio of the length L 2 (cm) to said inside diameter D 2 (cm) of the column satisfies the following formula (9),
2 ≦L 2 /D 2 ≦40 (9),
(4) said number of stages n 2 satisfies the following formula (10),
10≦n 2 ≦80 (10),
(5) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 21 (cm) of the gas outlet satisfies the following formula (11),
2 ≦D 2 /d 21 ≦15 (11), and
(6) a ratio of said inside diameter D 2 (cm) of the column to said inside diameter d 22 (cm) of the liquid outlet satisfies the following formula (12),
5 ≦D 2 /d 22 ≦30 (12).
21. The reactive distillation apparatus according to claim 20 , wherein d 11 and d 12 satisfy the following formula (13), and d 21 and d 22 satisfy the following formula (14)
1 ≦d 12 /d 11 ≦5 (13)
1 ≦d 21 /d 22 ≦6 (14).
22. The reactive distillation apparatus according to claim 20 , wherein L 1 , D 1 , L 1 /D 1 , n 1 , D 1 /d 11 , and D 1 /d 12 for said first continuous multi-stage distillation column satisfy the following formulae: 2000≦L 1 ≦6000, 150≦D 1 ≦1000, 3≦L 1 /D 1 ≦30, 30≦n 1 ≦100, 8≦D 1 /d 11 ≦25, and 5≦D 1 /d 12 ≦18, respectively, and
L 2 , D 2 , L 2 /D 2 , n 2 , D 2 /d 21 , and D 2 /d 22 for said second continuous multi-stage distillation column satisfy the following formulae: 2000≦L 2 ≦6000, 150≦D 2 ≦1000, 3≦L 2 /D 2 ≦30, 15≦n 2 ≦60, 2.5≦D 2 /d 21 ≦12, and 7≦D 2 /d 22 ≦25, respectively.
23. The reactive distillation apparatus according to claim 20 , wherein L 1 , D 1 , L 1 /D 1 , n 1 , D 1 /d 11 , and D 1 /d 12 for said first continuous multi-stage distillation column satisfy the following formulae: 2500≦L 1 ≦5000, 200≦D 1 ≦800, 5≦L 1 /D 1 ≦15, 40≦n 1 ≦90, 10≦D 1 /d 11 ≦25, and 7≦D 1 /d 12 ≦15, respectively, and
L 2 , D 2 , L 2 /D 2 , n 2 , D 2 /d 21 , and D 2 /d 22 for said second continuous multi-stage distillation column satisfy the following formulae: 2500≦L 2 ≦5000, 200≦D 2 ≦800, 5≦L 2 /D 2 ≦15, 20≦n 2 ≦50, 3≦D 2 /d 21 ≦10, and 9≦D 2 /d 22 ≦20, respectively.
24. The reactive distillation apparatus according to claim 20 , wherein each of said first continuous multi-stage distillation column and said second continuous multi-stage distillation column is a distillation column having a tray and/or a packing as the internal.
25. The reactive distillation apparatus according to claim 24 , wherein said first continuous multi-stage distillation column is a plate-type distillation column having the tray as the internal, and said second continuous multi-stage distillation column is a distillation column having both the packing and the tray as the internal.
26. The reactive distillation apparatus according to claim 24 , wherein each of the trays in said first continuous multi-stage distillation column and said second continuous multi-stage distillation column is a sieve tray having a sieve portion and a down comer portion.
27. The reactive distillation apparatus according to claim 26 , wherein said sieve tray has 100 to 1000 holes/m 2 in the sieve portion.
28. The reactive distillation apparatus according to claim 26 , wherein the cross-sectional area per hole of said sieve tray is in a range of from 0.5 to 5 cm 2 .
29. The process according to claim 24 , wherein said second continuous multi-stage distillation column is a distillation column having, as said internal, the packing in an upper portion of the column, and the tray in a lower portion of the column.
30. The reactive distillation apparatus according to claim 24 , wherein said packing of said internal in said second continuous multi-stage distillation column is one or more of a structured packing.
31. The reactive distillation apparatus according to claim 30 , wherein said structured packing in said second continuous multi-stage distillation column is of at least one selected from the group consisting of Mellapak, Gempak, TECHNO-PAK, FLEXI-PAK, a Sulzer packing, a Goodroll packing and a Glitchgrid.
32. The reactive distillation apparatus according to claim 20 , wherein said first continuous multi-stage distillation column comprises two or more of distillation columns.
33. The reactive distillation apparatus according to claim 20 , wherein said second continuous multi-stage distillation column comprises two or more of distillation columns.