US2739176A

US2739176A - Removal of ketone impurities in the preparation of butadiene-1,3

Info

Publication number: US2739176A
Application number: US305886A
Authority: US
Inventors: Reilly Park Mcknight; Carwardine John Edgar Douglas; Finigan Charles Milne
Original assignee: Polymer Corp
Current assignee: Polysar Ltd; Polymer Corp
Priority date: 1952-08-14
Filing date: 1952-08-22
Publication date: 1956-03-20
Anticipated expiration: 1973-03-20

Description

March 20, 1956 P. MOKQREILLY ETAL 2,739,176 I v REMOVAL OF KETONE IMPURITIES IN THE PREPARATION OF BUTADIENE-1,3 Filed Aug. 22, 19

INVENTORS PARK MKNIGHTRE/LL Y JOHN [DOA/P DOUGLAS (REWARD/NE 7 CHARLES M/LA/E F/IVIGA N Y Bow AEM'M r ATTORA/ Y8 -2,739,176 'R'EMovA-L orixn'ronnnurunrrtss in Tris runrxnarronor BUTXDlE-NE-itfi Park McKnight Reilly, John Edgar Douglas Carwardine, and Charles Milne Finigan, Sarnia, Ontario, Canada, assignors to Polymer Corporation Limited, Sarnia, Gin tario, Canada, a corporation of Canada Application August 22, 1952, Serial No. 305,886 Claims priority, application Canada August 14, N52

3 Claims. (Cl. 260-56815 This invention relates to theremoval of ketone impurities in the preparation of butadiene-1,3.

More particularly, the invention is concerned with such removal during the known process for the preparation of butadiene-1,3 which comprises the steps of dehydrogenating, utilising a calcium-nickel phosphate catalyst, a hydrocarbon mixture containing a substantial quantity of C4 hydrocarbon of greater saturation than butadiene-1,3, e. g. normal butylene; fractionating the reaction products to isolate the C4 fraction; and extracting butadiene-1,3 from extracts the butadiene-1,3 and any acetylenes from the C4 fraction.

Copending application Serial No. 285,832 by Cotton et al., filed May 2, 1952, describes the removal of acetylenes so that they do not contaminate either the copper ammonium acetate or the butadiene product. This is effected by performing the extraction in two steps, firstly contacting the C4 fraction with a relatively small amount of the copper ammonium acetate whereby the more soluble acetylenes are removed, and secondly contacting the substantially acetylene-free C4 fraction with a relatively large amount of the copper ammonium acetate to extract the butadiene.

In this specification, the calcium-nickel phosphate catalyst is the promoted catalyst described broadly in Dow Chemical Companys United States Patent No. 2,442,320. The copper ammonium acetate solvent is, as is well known, mainly composed of cuprous ammonium acetate but also contains at least a small amount of cupric ammonium acetate.

In the above known process using the calcium-nickel I tion with copper ammonium acetate, at least most of the ketones formed during the dehydrogenation reaction. The most convenient method of removing the ketones is by means of extraction with water and this is preferably effected prior to the fractionation step, though it may be efiected after the fractionation step.

The present invention, quite apart from improving the dissolution of the butadiene in the copper ammonium ac etate, reduces ketone impurities in the butadiene finally extracted and provides a useful method of obtaining ketones as a by-product. The yield of ketones may be im- Unit fi ms ,1

,. Mar. 20 1956 proved by introducingadditional acetiylenes so as to be present during the dehydrogenation reaction. Such additional acetyle'nes may be recycled from thenlater acetylene extraction stage described above in connection with copending application Serial .No. 235,832.

The invention is illustrated in the accompanying drawing which shows a flow diagram of a ketone removal circuit adapting a washing tower, or so-called quench "r connected-topipe 8 *by 'aapump 12 and a, pipe .13. A pipe 14 carries steam into tower 10 to strip ketones from the water, the ketones leaving tower by a pipe 15. A pipe 16 fitted with a valve 17 connects pipe 13 to waste.

In the preparation of butadiene-1,3 a gaseous mixture of hydrocarbons is'dehydrogenated in a reactor containing a calcium-nickel phosphate catalyst and maintained at a temperature of 1000- 1200 F. The effluent gaseous reaction product may contain about 0.8% by weight of ketones formed during the reaction. These gases are passed through coolers until their temperature is in the region of 160 F. and are then passed into the tower 1 via the inlet pipe 3. The gases pass up the tower 1 through the layers 2 of packing and are washed by water I entering the top of the tower 1 from the pipe 8. The

water removes most of the ketones in the gases and the substantially ketone-free gases leave the tower 1 via the outlet pipe 4 whence they proceed to fractionation and extraction with copper ammonium acetate as previously described. The tower 1 efiects a cooling of the gases to about 80 F.

A portion ofthe water collecting at the bottom of tower 1 and containing extracted ketones is removed via pipe 5 and pump 6 to the stripping tower 10 where the ketones are extracted and removed via outlet pipe 15. The substantially ketone-free water is returned from the botttom of the tower 10 to the tower 1 via pipe 11, pump 12 and pipes 13 and 8.

A quantity of Water vapour is present in the dehydrogenation reaction products and much of this will condense in the tower 1 so that the quantity of water circulating will continuously tend to increase. It is thus necessary to remove water either continuously or at intervals via the branch pipe 16 and valve 17. The valve 17 may be controlled automatically in accordance with the level of water in the bottom of tower 1.

The quantity of water required to be circulated through the tower 10 will depend on the particular circumstances of each case and particularly on the quantity of ketones contained in the gases. With a normal rate of flow of the gases, 30,000 lb. of water per hour has been found satisfactory.

Where it is possible to dispose of waste water containing ketones and Where the ketones are not required to be recovered, the fractionation vessel may be dispensed with, fresh water passed into the top of the tower 1 and, ketonecontaining water discharged to waste. A recirculation circuit may still be used and in this case, ketone-containing water may be removed through a valve from time to time or by a continuous bleed.

We claim:

1. A process for the preparation of butadiene-1,3 com-' cfiiuent'of the dehydrogenation reaction with water to extract substantially all of the ketones formed during the.

dehydrogenation reaction, fractionating the washed efiiuent to isolate the C4 fraction,"-and extracting butadiene-1,3 from the C4 fraction with copper ammonium acetate.

2. A process for the preparation of butadiene-l,3 comprising dehydrogenating at elevated temperature an n-butylene-rich gaseous hydrocarbon mixture utilizing a calcium-nickel phosphate catalyst whereby substantial quantities of butadiene-1,3 are formed, washing the gas- 7 eous eifiuent of the dehydrogenation reaction in a washbutylene-rich gaseous hydrocarbon mixture utilizing a calcium-nickel phosphate catalyst whereby substantial quantities of butadiene-1,3 areformed, washing the gaseous eifiuent of the dehydrogenation reaction with substantially alkali-free water to extract substantially all of the ketones formed during the dehydrogenation reaction, fractionating the washed efiluent to isolate the C4 fraction, and extracting butadiene-1,3 from the C4 fraction with copper ammonium acetate.

References Cited in the file of this patent UNITED STATES PATENTS Querforth Oct. 3, I933 Ipatieif et al Aug. 19, 1941 Asbury et al June 11, 1946 McCombie Apr. 1, 1947 Britton et al. May 25, 1948 Murphree Oct. 12, 1948 Engel Sept. 26, 1950

Claims

1. A PROCESS FOR THE PREPARATION OF BUTADIENE-1,3 COMPRISING DEHYDROGENATING AT ELEVATED TEMPERATURE AN NBUTYLENE-RICH GASEOUS HYDROCARBON MIXTURE UTILIZING A CALCIUM-NICKEL PHOSPHATE CATALYST WHEREBY SUBSTANTIAL QUANTITIES OF BUTADIENE-1,3 ARE FORMED, WASHING THE GASEOUS EFFLUENT OF THE DEHYDROGENATION REACTION WITH WATER TO EXTRACT SUBSTANTIALLY ALL OF THE KETONES FORMED DURING THE DEHYDROGENATION REACTION, FRACTIONATING THE WASHED EFFLUENT TO ISOLATE THE C4 FRACTION, AND EXTRACTING BUTADIENE-1,3 FROM THE C4 FRACTION WITH COPPER AMMONIUM ACETATE.