US2384984A - Manufacture of styrene and ethylbenzene - Google Patents

Description

Patented Sept. 18, 1945 UNITED STATES @PATENT OFFICE" V \ass'issi Q MANUFACTURE OF STYBENE AND ETHYLBENZENE Charles Weizmann, London, England No Drawing. Application June 11, 1043, Serial No. 490,518. In France January 17, 1940 temperature within the range of sorts 725 0.,

at substantially atmospheric pressures and ate. space velocity ranging from about 0.01 to 0.1 liter of oleilns, calculated on the liquid basis, per liter of catalyst per hour, and recovering from the reaction products a principal fraction having a boiling point range of about 120-150" C. consisting substantially of styrene and ethylbenzene: the catalyst used in said process being preferably selected from a group consisting of iron, copper, nickel. cobalt, molybdenum, manganese, tungsten, vanadium, silver and the platinum metals: all as more fully hereinafter set forth and as claimed.

This application is a continuation-in-part {bf my copending application, Serial illed October 29, 1940. Q

It has been known for years that it is possible to convert olefins at least partly into aromatic hydrocarbons byheating them in the presence of metal catalysts under suitable conditions. The

Number 363.3%,

various processes described in the prior art have. i

usually been conducted in such fashion that the principal product has been benzene. In the British patent to Greenstreet, No. 412,933. for example, mixtures of olefinic and paraiiinic hydrocarbons are heated within the temperature range of 600-1200 C. (preferably '700-850" C.) in contact with various solid materials including metals, and at atmospheric or higher pressures. The products produced are said to be largely aromatic in nature and to consist principally of benzene.

It has apparently not :beerr recognized by prior art investigators that. if the conditions of the process, including temperature and space velocity are carefully selected, it is possible to produce a product which is substantially completely aromatic, the largest part of which consists of a fraction, boiling between about 120 to 150 which consists substantially of ethylbenzene and styrene. when operated in this fashion the secondary breakdown to benzene does not occuras it does in the prior art processes."

Ethylbenzene and styrene are, of course. the most valuable or the aromatics obtainable in any large quantities from such processes. Styrene forms the basis for a number of important thetic resins. and for Buns-S synthetic rubber;

8 Claims. 260-873) dition, it can be readily converted into styrene.

The present invention consists in a process for the manufacture of aromatic hydrocarbons having eight carbon atoms in the course of which light oleflnes of low molecular weight, having from 2-5 carbon atoms are'passed over a finely divided metallic catalyst "of the hydrogenation and dehydrogenation type'at a temperature between about 600 to 725 C. and preferably at about atmospheric pressure.

The invention also consists in a process as set forth in the preceding paragraph according to which the metallic catalyst is a metal or alloy or mechanical mixture of metals or alloys capable of catalyzing hydrogenation or dehydrogenation reactions and is used preferably in such a form as to present a large contact surface to the reacting material.

The invention also consists in a process as set forth in the preceding paragraphs wherein the olefin, e. g. butylene, is passed through a steel. tube containing. the catalyst in the form of re- .ing reduced copper wire gauze heated to 700 C.

The space velocity employed in this operation was 0.05 liter of butylene, calculated on the liquid basis, per liter of catalyst per hour. The eli'iuent from this-tube was cooled and condensed. -'l5 per cent, of this liquid product distilled below 180 C. at atmospheric pressure. The residue crystallized spontaneously and consisted of naphthaiene and small quantities of other polycyclic aromatic hydrocarbons. Upon careful fractionation of the light fraction, (boiling up to 180 C.) the following fractions were obtained:

. Percent Boiling below benzene 2 Benzene 30 Toluene 8 Ethylbenzene and styrene 45 Styrene 15 The ratio of ethylbenzene to styrene obtained in myprocess depends to some extent upon the while ethylbenzene is characterized by having I the very high octane number of 128 and, in adtemperature employed in the reaction zone. If

or of naphthalene, phenanthrene and anthracene are obtained. For example at lower temperatures the yield in low boiling aromatics is higher while at higher temperatures the polycyclic hydrocarbons are formed in greater quantities. At a temperature of about 700 C. the yield of styrene and ethylbenzene reaches a maximum.

While I have described what I consider to be the best embodiments of this invention, it is evident, of course, that various modifications of the specific procedures described can be made without departing from the purview of this invention. The metals found most satisfactory for use as catalysts include copper, iron, nickel, cobalt, manganese, tungsten, vanadium, molybdenum, silver and the platinum metals. It is also possible to employ mixtures of these metals as catalysts, as w ll as alloys containing a plurality of these met s. In fact any metal capable of promoting hydrogenating and dehydrogenating reactions' can be employed. Other modifications of my process which fall within the scope of the following claims will be immediately evident to those skilled in this art,

What I claim is: 1. In the manufacture of styrene and ethylbenzene, the process which comprises passing a low molecular olefin through a conversion zone, containing a finely divided metal hydrogenating: dehydrogenating catalyst, at substantially atmos-= pheric pressure, at a temperature within the range of about 600 to 725 C. and at a-space velocity ranging from about 0.01 to 0.1 liter of olefin,

calculated on the liquid basis, per liter of catalyst per hour, and fractionating the resulting products to obtain a principal fraction boiling between about 120 to 150 C. consisting substantially of styrene and ethylbenzene.

2. In the manufacture of styrene and ethylbenzene, the process which comprises passing an olefin containing from 2 to 5 carbon atoms basis, per liter of catalyst per hour and fractionatlng the resulting products to obtain styrene and ethylbenzene in principal proportions.

l. In the manufacture of styrene and ethylbenzene, the process which comprises passing an olefin containing from 2 to 5 carbon atoms through a conversion zone containing a finely divided metal hydrogenating-dehydrogenating catalyst at substantially atmospheric pressure, at a temperature of about 700" C. and at a space velocity ranging from about 0.01 to 0.1 liter of olefin, calculated on a liquid basis, per liter of catalyst per hour, whereby styrene and ethyl benzene are produced as a principal product, and fractionating the reaction products to recover said styrene and ethylbenzene.

5. The process of claim 2 wherein said olefin is butylene.

6. The process of claim 4 wherein said olefin is butylene.

7. In the manufacture of styrene and ethylbenzene, the process which comprises passing butylene through a conversion zone containing finely divided copper at substantially atmospheric pressure, at a temperature of about 700 C. and at a space velocity of about 0.05 liter of butylene, calculated on a liquid basis, per liter of catalyst per hour, whereby styrene and ethylbenzene are formed as a principal product, and fracrtionating the reaction products to recover said styrene and ethylbenzene.

8. In the production of aromatics by the cata-