US1380277A - Catalytic oxidation of ortho-cresol - Google Patents

Description

'catalyzers.

UNITED STATES PATENT OFFICE.

JOHN M. WEISS,

JERSEY, ASSIGNORS TO THE BARRETT 00 OF NEW YORK, N. Y., AND CHARLES R. DOWNS, OF OLIFFSIDE, NEW

MPANY, A CORPORATION OF NEW JERSEY.

CATALYTIC OXIDATION OF OBTHO-GRESOL.

No Drawing.

To all whom it may concern:

Be it known that we, JOHN M. Wnrss and CHARLES R. Downs, citizens of the United States, residing at (1) 210 West 110th street, New York city, and 3g2) Cliffside, in the counties of (1) New ork and 2) Bergen and States (1 New York, (2) ew Jersey, have invente certain ,new and useful Improvements in Catalytic Oxidation of Ortho Cresol, of which the following is a specification.

This invention relates to the catalytic oxidation of ortho-cresol and to the production of products of partial oxidation therefrom. It comprises the partial or selective oxidation of ortho-cresol by oxidation, either alone or mixed with diluents or by means of the oxygen containing gas in the presence of a catalyzer to form salicylaldehyde, salicylic acid, or both. The invention is based upon the discovery that by subjecting ortho-cresol, 0 1-1 0, to oxidation in the presence of an appropriate catalyzer, and at an appropriate temperature a selective or partial oxidation thereof takes place with the formation of an oxidation product or products such as salicylaldehyde or salicylic acid. We have conditions, the ortho-cresol may be changed to salicylaldehyde or salicylic acid without effecting the complete combustion of a very large proportion of the material treated. The invention may be practised by subjecting the ortho-cresol in the vapor phase mixed with air or with oxygen either alone or admixed with other diluent gases or with certain oxygen containing gases, to a suitable temperature in the resence of certain I The use of 0 has been found to be especially useful in this connection as a diluent gas. It has been found that many oxids of metals are suitable as catalyzers. More especially iron oxids, alminiumoxid and oxids of the fifth and sixth groups of elements in the periodic system, and more I particularly molybdenum oxid, have been found to be especially useful as catalyzers in this process.

By suitably regulating the conditions such as temperature, pressure and presence of diluents and operating with proper 'c'atalysts, the degree of oxidation can be controlled whereby the ortho-cresol is oxidized Specification of Letters Patent.

found that under proper Patented May 31, 1921.

Application fiIed December 12, 1919. Serial No. 344,370.

in a particular manner to an oxidation short of what is commonly known as complete combustion to produce salicylaldehyde or salicylic acid.

, The invention will be explained in connection with the following example, which is given for illustrative purposes. It is not intended to limit the procedure to the exact details given as the process can be varied throughout wide limits without departing from the spirit and scope of the invention.

A mixture of ortho-cresol and air in the vapor phase is passed through tubes at, a temperature of about 250 C. to 500? C., the tubes containing molybdenum oxid deposited on crushed pumice with the result that salicylaldehyde and salicylic acid are produced. Instead of introducing oxygen as oxygen of the air, oxygen gas may be used either alone or diluted with nitrogen or other inert gas; the proportion of oxygen to orthocresol may be varied; the catalyzer may be deposited on crushed pumice or other suitable powdered, granulated or fibrous material which is chemically inactive and acts merely as a mechanical distributer; the rate at which, the mixture is passed through the tubes may be regulated to suit the needs;

the tubes may be varied in length or diameter or confined spaces other than tubes may be used in which to place the catalyzer; instead of molybdenum oxid, other compounds may be used as a catalyzer. It is essential that hot ortho-cresol in the vapor .phase shall come in contact with the catalyzer in the presence of ox gen for the proper reaction to take place. he introduction of a diluent gas is a convenient way to assist in regulation of the reaction. It has molecule of ortho-cresol to three atoms of oxygen to produce salicylic acid fromjorthocresol. The following equations are suggested as representing the reactions which take place, although it is not desired to limit the reactions to any particular theory. The

moist air, instead of dry air,

equations are given to explain the reactions as indicated by the results obtained.

+H0 CHO Where considerable excess of ortho-cresol is used over and above that which is oxidized, the remaining ortho-cresol will 1n Water is practically always formed as 'a sures The oxidizing efiect can be dation.

product some steam is present as a consequence.

The ortho-cresol used should preferably be of high purity or if admixed with impurities, it should be substantially free from impurities of a character as would prejudice the desireselectiv and partial catalytic oxi- It' will be evident that various'types of apparatus may beused for carrying out the process of the present invention and for bringing reactin gases with the catalyst, and for maintaining the proper temperature for the catalytic reaction. Accordingly, we do not deem it necessa to describe in further detail such types o i apparatus.

It will'be evident also that the various conditions oi: the reaction are capable of variation. Among these conditions may be mentioned the temperature and pressure at which the reaction is carried out, the time 0t contact of t e reactive gases with the catalyst, the proportion of catalyst to the reacting gases,

gases, such,'as nitrogen or CO The reaction may thus be carried out at atmospheric pressure, or at increased or diminished presmodified by further diluting the reacting gases, as by returning the air, the reaction, to dilute the reacting gases in the 'further carrying outof the process,

orby mixing oxygen w1th the air to lncrease,

the. oxygen content thereof, or by using oxy oxygen in admixture with other gases than those contained in air, etc.

It will evident contact of the reacting gases with the catalyst can .be varied by increasing the catalytic 1 mass or bydecreasing the speed at which the reacting gases am through or in contact with the catalyst. These and like variations about the necessary contact of the and the relative pro-portions of ortho-cresol and oxygen and of diluent impovished in oxygen by i also that the time of I will correspondingly modify and aifect the catalytic'oxidation.

Salicylaldehyde and salicylic acid areapparently intermediate products of the incomplete oxidation of ortho-cresol. In the operation of this process, under proper conditions, there has been found to be very little com lete combustion, thus indicating that practically all of the ortho-cresol which is oxidized is changed to salicylaldehyde or. salicylic acid. .Any of the ortho-cresol which passes through the process unchanged maybe separated from the other productsby sublimation, crystallization, distillation, etc, and may again passed through the reaction zone mixed with oxygen'or mixed with a sufiicient supply of ortho-cresol and'oxygen, if desired, and more temperature from about 250 C. to 500 C. with an oxygen containing gas in the presence of a metallic oxid as a catalyst.

4. The method of'producing' salicylaldehyde and salicylic acid which comprises oxidizing ortho-cresol in the va or phase at a temperature of about 250 to 500 C. with an oxy en containing gas in the presence of molyhdenum oxid as a catalyst.

5. The method of producing salieylaldeand salicylic acid which comprises oxi-.

hyde dizing ortho-cresol in the vapor phase with an. oxygen containing gas inthe presence of a metallic oxid as a catalyst, separating the salicylaldehyde and salicylic acid from any unchanged ortho-cresoland returning the ortho-cresol'for a similar oxidizing treatment. I

6. The method ofproducing salicylaldehyde and salicylic acid which comprises oxidizing ortho-cresol in the vapor phase with an oxygen containing gasin the-presence of molybdenum oxid as a-catalyst, separatgen alone wihout other diluent, or by using ing the salicylaldehyde and salicylic acid from any unchanged ortho-cresol and re- -turning the ortho-cresol for a-similar oxi-- dizin treatment.

- 7. he method of roducing salicylalde hyde and salicylic acid which comprises oxidizing ortho-cresol in the vapor phase with an oxygen containing gas in the presence of a metallic oxid as a catalyst, at a tempera tureof from about 250 C. to 500 0., sepatemperature of from about 250 0. to 500 rating the salicylaldehyde and salicylic acid 0., separating the salicylaldehyde and salifrom any unchanged ortho-cresol and recylic acid from any unchanged ortho-cresol turning the ortho-cresol for a similar oxiand returning the ortho-cresol for a similar a dizing treatment. oxidizing treatment. 15 8. he method of producing salicylalde- In testimony whereof we afiix our signa-' hyde and salicylic acid which comprises oxit'ures. dizingortho-cresol in the vapor phase with an oxygen containing gas in the presence JOHN M. WEISS. 10 of molybdenum oxid as a catalyst, at a CHARLES R. DOWNS.