US2332298A

US2332298A - Manufacture of hydrocarbon products

Info

Publication number: US2332298A
Application number: US462898A
Authority: US
Inventors: Louis A Clarke; George B Hatch; Ernest F Pevere
Original assignee: Texaco Inc
Current assignee: Texaco Inc
Priority date: 1942-10-22
Filing date: 1942-10-22
Publication date: 1943-10-19
Anticipated expiration: 1960-10-19

Description

internatik 0a. 19, 1943 uNlTED sfrA'rs's PATENT oFFlcs MANUFACTURE oF HYDBOCARBON PRODUCTS ,Louis A. Clarke and George B. Hatch, Fishkill, and Ernest F. Pevere, Beacon, N. Y., assignors to The Texas Company, New Yorlr, N. Y., a

A.corporation ofv Delaware Application October 22, 1942, Serial No. 462,898

s claims. (ci. 26o-6831i e tion of sulfuric acid under suitable polymerizingy y conditions so as to effect substantial conversion of cli-isobutylene to tri-isobutylene Without substantial production of polymers of higher molecular weight than tri-isobutylene.

It has been known heretofore to treat isobutylene with ysulfuric acid under polymerizing conditions so as to' effect polymerization.y The result- 'ing polymer product obtained contains both diisobutylene and tri-isobutylene as well as higher molecular Weight polymers. According to the information available heretofore it would be exsulfuric acid under polymerizing conditions tetraisobutylene would be obtained.

However and in accordance with this invention, it has been found that contrary to normal expectations the dimer, di-isobutylene, can be subjected to the action of sulfuric acid so as to effect conversion of the dimer to the trmer without substantial production of the tetramer.

More speciflcally the invention involves treatying di-isobutylene or a hydrocarbon feed consisting essentially of di-isobutylene with sulfuric acid'of about 60 to 85% HaSO4 and preferably about 70% H2804. The treatment is effected at a temperature in the range about 100 to 250 F. and preferably within the range about 150 to 200 F., employing a time of contact between hydrocarbons and acid ranging from about l to 2 6 minutes. The acid may be employed in the pro- Y portion of about 0.3 to 3.0 volumes of acid per volume of dimer in the reaction zone, the prepeoted that when di-isobutylene is subjected to l Within the range about 285 toiOOo F. so that the fuel product will have an open-cup flash of not more than about 105 F. Tri-isobutylene, since it has'a boiling point of about 354 F., therefore, s

provides a desirable hydrocarbon component for safety fuel Whereas the dimer and tetramer compounds cannot be used in substantial amounts since they have boiling points outside this preferred range for safety fuel.

According to a modification of the invention iso-butylene or a C4 hydrocarbon fraction containing isobutylene may be treated with sulfuric acid under polymerizing conditions so as to ob,l

tain a product comprising the dimer and trimer as well as some other material including higher molecular Weight polymers and unreacted hydrocarbons. This product may be fractionated to separate therefrom a fraction consisting essentially of thedimer and this dimer fraction then subjected to further treatment with sulfuric acid in a separate treating zone in accordance with the procedure set forth above for conversion to the trimer. This preliminary treatment Yof the C4 fraction with sulfuric acid may involve the so-called 'cold sulfuric acid process for polymerization or the so-called hot acid polymerization process as will be described in more detail later.

In order to describe the invention further reference will now be made to the accompanying drawing. l

As indicated in the drawing a hydrocarbon feed consisting essentially of Ci hydrocarbons including isobutylene is conducted from a source not shownthrough a pipe I to an absorber Z wherein the feed hydrocarbons are subjected to countercurrent contact with sulfuric acid introduced through a pipe 3. The Aconditions of operation maintained in the absorber 2 correspond substantially to those employed in the conventional cold sulfuric acid process. Thus the acid introduced through the pipe 3 contains about 60 to H2804 and the temperature maintained within the absorber 2 is in the range about 60 to 100 F. I f

The acid and hydrocarbons are introduced in the ratio of about 1 part of acid per part of hydrocarbon by volume.

Under these conditions about of the isobutylene contained in the feed hydrocarbon mixture is absorbed in the acid. The unabsorbed hydrocarbons which may comprise normal parafns as well as some normal butylenes are discharged through a pipe 4.

The solution of isobutylene in sulfuric acid is mixture separates into phases. i continuously withdrawn and recycled all or -in a pipe 5 and passed through a heater 5 wherein polymerization is effected. The temperature in v the heater 6 is in the range about 140 to 200 F. and the reaction time is usually about 1 minute so that the polymer product may comprise about 75% dimer and 25% trimer. This product is continuously drawn ofiV to a separator l wherein the The acid phase is part through a pipe 8 to the previously mentioned pipe 3. The hydrocarbon phase is continuously drawn off through a pipe 9 to a fractionating still l wherein the hydrocarbons are subjected to fractionation .to segregate a fraction rich in the dimer. It '.wi11 be understood. of course, that prior to fractionation the hydrocarbons may be subjected to treatment with a neutralizing agent such as caustic soda or other suitable alkaline material for the purpose of removing remaining acid.

In the fractionation, a light fraction comprising isobutylene (monomer) may be removed through a pipe Ii and. this material may be recycled all or in part to the absorber'2.

An intermediate fraction consisting essentially of the dimer is removed through a pipe i2 while the higher boilingfraction comprising the trimer is removed through a pipe I8.

The dimer fraction is conducted through the pipe l2 to a polymerizer I4 wherein the fraction is subjected to further treatment with sulfuric acid to effect conversion to the trimer. The acid employed at this stage may contain from 60 to 85% I-IzSO-i and preferably about 70% HrSOi. The acid may be fresh, regenerated or used acid.

The reaction is effected at a temperature in the range about 100 to 250 F. and preferably in the range between 150 to 200 F. employing a contact time between acid and hydrocarbon undergoing treatment of to 20 minutes. The ratio of acid to dimer undergoing treatment is maintained within the range about 0.3 to 3.0 volumes of acid per volume of dimer.

The resulting polymer product is .conducted through a pipe I5 to a separator i5 wherein phase separation occurs. The acid phase is drawn off from a pipe il and may be recycled all or in part to the polymerizing unit I4.

The hydrocarbon phase is drawn off through a pipe i8 to a fractionating still I9, wherein the hydrocarbons are fractionated so as to separately recover the trimer and unreacted dimer. The unreacted dimer is advantageously returned through a pipe to the polymerizer i4 for further treatment. The small amount of lower 'molecular weight material may be removed as a separate fraction throughs. lpipe 2l while any higher boiling residue isseparated as another fraction and removed through a pipe 22, the trimer or trimer fraction being discharged through a pipe 23.

As already indicated the primary stage may involve the so-called hot acid polymerization process in which type of operation absorption and polymerization of isobutylene is eected in a single step. In this type of operation acid of about 63 to 70% H2504 is employed at a temperature in the range about 160 to 220 F. with a time of contact about 10 to 15 minutes.

By way of specic example a feed consisting of di-isobutylene is treated .in a continuous reactor with ,80% HzSOi acid, the reaction products being discharged to an acid settler wherein acid is separated from the hydrocarbon. The hydrocarbon is fed continuously to the reactor in which an acid to hydrocarbon volume ratio of 1.5:1 is maintained by acid recycle from the settler. The contact time for the hydrocarbons is fifteen minutes at a temperature of 120 F.

Thereafter the treated hydrocarbons are separated from the catalyst and fractionally distilled into three liquid fractions, namely, a dimer frac- 4tion boiling up to about 329 F., a trimer fraction boiling inthe range 329 to 365 F. and a residual fraction boiling above 365 F. The volume per cent of each fraction obtained is as follows:

Per cent Dmer fraction` 31.1 Trimerfraction-- 62.2 Residual fraction 6.7

Thus, it is seen that the feed hydrocarbon 1s converted into a product of which 62.2% by volume consists mainly of the trimer, the amount ol higher molecular weight polymer material being Y pound. In,the case of the two stage operation either substantially pure isobutylene or a normally gaseous hydrocarbon mixture comprising isobutylene may be used as the initial feed.

Obviously many modifications and variations of the invention, as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

\ l. The method of producing tri-isobutylene whichcomprises subjecting a feed hydrocarbon consisting essentially of di-isobutylene to the action of sulfuric acid having a concentration of.

about 60 to 85% H2804 at a temperature in the range about to'250 F. for a relatively short period of time such that di-isobutylene undergoes substantial conversion to tri-isobutylene with relatively small production of polymer material of higher molecular weight than tri-isobutylene, separating the treated hydrocarbons from the acid and removing tri-isobutylene from the treated hydrocarbon product.

2. The method of producing tri-'isobutylene which comprises subjecting a feed hydrocarbon consisting essentially of di-isobutylene to the action of sulfuric acid having a concentration of about l0 to 80% HaSOi at a temperature in the y range about to 200 F. for a relatively short period of time such that di-lsobutylene undergoes substantial conversion to tri-isobutylene with relatively small production of polymeric material of higher molecular weight than tri-isobutylene, separating the treated hydrocarbons from the acid and removing tri-isobutylene from the treated hydrocarbon product.

3. The method of producing tri-isobutylene which comprises subjecting a normally gaseous hydrocarbon feedv comprising isobutylene to the action of a polymerization catalyst under conditions such that a hydrocarbon mixture is obtained which contains di-isobutylene and tri-isobutylene, separating di-isobutylene from the hydrocarbon mixture, subjecting the di-isobutylene so obtained to the action of sulfuric acid having a concentration of about 60 to 85% H2504 at a temperance inthe range about mo tu 250 E. :or

a relatively short period of time such that dibutylene, separatingdi-isobutylene from the hydrccarbon mixture, subjecting the di-isobutylenev so obtainedl to the action of sulfuric acid having asaaaoaf" l l 3 a concentration of about 70 to 80% H2804 at a temperature in the range about 150 to 200 F. for

a relatively short period of time such that di. isobutylene undergoes substantial conversion tov tri-isobutylene with relatively small production of polymer material of higher molecular weight than trl-isobutylene, separating the treated hydrocarbons from the acid and removing trl-iso- '-butylene from the treated hydrocarbon product.

5. The method according to claim 3 in which the isobutylene feed is polymerized by the action of sulfuric acid containing about 60 to '70% H2SO4 and at a temperature in the range 40 to 200 F. v

LOUIS A. CLARKE. GEORGE B. HATCH. ERNEST E. PEVERE.