US1321994A - Stjxfonation oe hydrocarbons with soa - Google Patents

Description

lit

water is formed as a by-product.

' UNITED srn'rns PATENT onnrcn.

CHARLES R. DOWNS, OF CLIFFSIDE, NEW JERSEY, ASSIGNOR 1'0 THE BARRETT COMPANY, A. CORPORATION OF NEW JERSEY.

SULFONATION OF HYDROGARBONS WITH S03 no Drawing.

To all whom it may concern:

"Be it known that I, CHARLns R. Downs, a citizen of the United States, residing at Olifiside, in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in.Sulfonation of Hydrocarbons with S0,, of which the following is a specification.

This invention relates to a method of sulfonating hydrocarbons by means of sulfur trioxid. It relates more particularly to the sulfonation of aromatic hydrocarbons by the use of gaseous S0,. The invention has particular application in the sulfonation of benzene and naphthalene in the vapor phase to reduce the monoor higher sulfonic aci s by means of gaseous SO, such as the ordinary gas mixture obtained from the usual contact chamber for producing S It is well known that when aromatic hydrocarbons are treated with sulfuric acid, Due to the formation of water during ,the sulfonation it is necessary either to use more sulfuric acid than would otherwise be required,

because of the consequent dilution of the sulfuric acid, or the water must be removed during the sulfonation process in order for the sulfonation to be completed.

When aromatic hydrocarbons aretreated in the liquid phase with SO to sulfonate the same, it is desirable to use pure SO in order to avoid contamination of the prodnets with objectionable matter which is not easily removed. Since the ordinary SO from the contact chambers is usually mixed with some S0,, and nitrogen and other impurities, the sulfonation products will be conglaminated when such impure S0 is use By my invention it is possible to use SO from the contact chambers for the sulfonation of aromatic hydrocarbons, thereby obviating the formation of water as a by-prodnot, and also preventing the mixture of other iropurities with the sulfonic acids to any appreciable extent. In carrying out this invention thearomatic hydrocarbon in the vapor phase, admixed with SO from the contact chambers, is passed through vessels or tubes heated to the proper temperature for the sulfonation to take place. The rapidity and degree of sulfonation and the formation of the mono-sulfonic acid or higher sulfonic acids and the position that Specification of Letters Eatent.

Patented Nov. 18, 1919.

Application filed .Tune 11, 1919. Serial No. 303,338.

the 'sulfonic acid group will take will depend upon many factors such as the temperature at which the reaction is caused to take place, the length of time the S0 is kept in contact with the hydrocarbon, the dilution of the S0 with blanketing gases, such as nitrogen, the particular hydrocarbon used, and the pressure that is maintained in thesystem. These factors can be easily ascertained by trial so as to produce the desired results. When the proper proportion of hydrocarbon and S0 is passed through the hot space substantially all of the S0 will react without the formation of any water, or the waste of a substantial amount of 80,. For example, if the theoretically correct amount of S0 is passed with naphthalene in the vapor phase through a tube heated between about 90 C. and 180 (1, the mono-sulfonic acids of naphthalene will be mainly formed. 1

Upon exit of the reaction products from the hot-reaction chamber, the sulfonic acid will be easily condensed due to the fact that sulfonic acids have low 'vapor pressures, while the other gases, if present, will pass off. In this way. a substantially pure sul- I fonic acid will be condensed which is free from the presence of sulfuric acid or other substituting a hydroxyl for the sulfo radical of the sulfonic acid. This present invention avoids this difficulty since the substantially pure sulfonic acid resulting from the condensation of sulfonic acid vapor can be neutralized directly by caustic or weak acid salts of the alkaline metals without the necessity of precipitating GaSO For this neutralization it is possible to use a caustic soda solution of such strengththat the sodium salt of the sulfonic acid is obtained as a water solution of proper concentration to be used for the purpose above mentioned.

While this process has been articularly described in connection with t e sulfonation of naphthalene, it is applicable to other hydrocarbons, particularly benzene and its homologues.

I clalm: V

1. The herein described process which comprises treating an aromatic hydrocarbon in the vapor phase with a gas containing SO under such conditions as to efiect sulfonation of the aromatic hydrocarbon.

2. The herein described process which comprises treating an aromat1c hydrocarbon in the vapor phase with a gas containing S0 under such conditions as to efiect sulfonation of the aromatic hydrocarbon, and condensing the sulfonic acids thereby formed.

' 3. The herein described process whichcomprises treating an aromatic hydrocarbon in the vapor phase with a gas containing S0 under such conditions as to effect sulfonation of the aromatic hydrocarbon, condensing the sulfonic acids thereby formed, and permitting the uncondensed gas to escape.

4. The herein described process which comprises treating an aromatlc hydrocarbon in the vapor phase with gaseous SO under such conditions as to efiect sulfonationof the aromatic hydrocarbon.

5. The herein described process which comprises treating an aromatlc hydrocarbon in -the vapor phase with aseous SO under such conditions as to e ect sulfonation of the aromatic hydrocarbon, and condensing the sulfonic acids thereby formed.

6. The herein described process which comprises treating an aromatic hydrocarbon in t e vapor phase with a gas containing S0 under such conditions as to efi'ect sulfonation of the aromatic hydrocarbon, condensing the sulfonic acids thereby formed,

I and directly neutralizing .said acids.

7. The herein described process which comprises treating an aromatic hydrocarbon in the vapor phase with a gas containing SO under such conditions as to effect sulfonation of the aromatic hydrocarbon, condensing the sulfonic acids thereby formed, and directly neutralizing said acids with a compound containing an alkali.

8. The herein described process which comprises treating an aromatic hydrocarbon in the vapor phase with a gas containing SO under such conditions as to effect sulfonation of the aromatic hydrocarbon, condensing the sulfonic acids thereby formed, and directly neutralizing said acids with caustic soda solution of such concentration that a water solution of sodium sulfonate will'be formed.

9. The herein described process which comprises treating naphthalene in the vapor phase'with a gas containin SO under such conditions as to eifect su fonation of the naphthalene.

10. The herein described process which comprises treating naphthalene in the vapor phase with a gas containing SO under such conditions as to effect sulfonation of the naphthalene, condensing and neutralizing the sulfonic acid thereby formed.

11. The herein described process which comprises passing naphthalene and S0 through a confined space at a temperature between 90 CL and 180 C.

12. The herein described process which comprises treating naphthalene in the vapor phase with a gas containing SO under such conditions as to effect sulfonation of the naphthalene, and condensing the sulfonlc acid thereby formed at a temperature below that at which the major portion of the other gases will be condensed.

In testimony whereof I aflix my signature.

CHARLES R. DOWNS.