US2343870A - Manufacture of alkylated benzene hydrocarbons - Google Patents

Description

W. KAPLAN March 14, 1944..

MANUFACTURE OF ALKYLATED BENZENE HYDROCARBONS Filed March 29, 1939 2 Sheets-Sheet 1 x llhxl KuZwuwE Nu munzmozou N8 5335 Z 02-04mm .5535 Q% INVENTOR WILL/AM KAPLAN ATTORNEY W. KAPLAN March 14, 1944.

MANUFACTURE OF ALKYLATED BENZENE HYDROCARBONS '2 Sheets-Sheet 2 File d March 29, 1959 .Aldll Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE- MANUFACTURE OF ALKYLATED BENZENE HYDROCABBONS I William Kaplan, Malverne, N. 2., assignor to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania Application ltiarch 29, 1939, Serial No. 264,693

4 Claims.

phase, the cracking results in the formation of a gasoline, the percent formed being roughly proportional to the time of digestion during the earlier stages of vcracking. The gasoline will contain 50% or more of olefins; 5% to of aromatics, depending on the digestion temperature and the nature of the charging oil; and the balance will be comprised of naphthenes and parafllnes. The chemical composition of the gasoline will remain substantially constant during the earlier stages of the cracking, that is, there will be very little variation in the composition at say 5% gasoline or at gasoline formoderate proportion of aromatics are formed, (say to 40% in the gasoline fraction), and allowing the reaction involving further aromatic formation to take place at a lowertemperature in the presence of a catalyst under conditions which result ,in the formation of appreciably smaller quantities of fixed gas.

Therefore, the primary object of the present invention is to provide an improved process for the manufacture ,of aromatic hydrocarbons, and more particularly aromatic compounds containing side-chains, and at the same time avoid the excessive loss usually encountered in known purely thermal processes of the type referred to.

A further object of the invention is to provide an improved process for the manufacture of side chain cyclic and aromatic hydrocarbons mation in a single pass. However, if the digestion is continued long enough, exothermic reactions take place which result in an increase in the proportion of aromatics in the gasoline fraction, with a reduction in the proportion of unsaturates and other constituents. This exothermic reaction can be stopped at any desired point so as to obtain a product of any desired aromatic content. However, the exothermic reaction proceeds with the production of excessive amounts of fixed gas, and the greater the percentage of aromatics in the gasoline,-the greater is the gas loss. As an example of such a process, a hydrocarbon oil such as naphtha,.kerosene, or gas oil, is heated and vaporized, and the resulting vapors subjected to a long time thermal conversion treatment at temperatures of about 950 F. to 1050 F. at a pressure of from 200 to 500 lbs. per square inch. The original charging stock is converted into a gasoline product containing from 40% to about 90% of aromatic hydrocarbons, depending upon the length of the reaction period, with a gas loss of from 30% to 40% of the original charging stock.

The process of the present invention is more particularly an improvement on this prior process for manufacturing aromatic hydrocarbons. The present invention contemplates stopping the high temperature exothermic reaction when a from mineral oils in order to provide such hydrocarbons for various purposes such as solvents, chemicals, and compounds, for use as blending agents to increase the anti-knock value of relatively poor gasolines.

Accordingly, the improved process of the present invention comprises the steps of subjecting a hydrocarbon oil such as a gas oil, kerosene or naphtha, to a thermal conversion operation preferably while flowing in a confined stream of restricted cross section through a long heated pipe coil, heating the oil to a temperature of from about 980 to 1020 F. at a pressure of approximately 250 lbs. per square inch,'maintaining the hydrocarbon oil at approximately said temperature or slightly higher, for a period of time sufflcient to convert the oil into a product containing a substantial proportion of condensable constituents boiling below about i00 F.. which contains approximately 35% of aromatic hydrocarbons, and approximately 45% of oleflnic type hydrocarbons, thereafter subjecting the vaporous products from the heating operation, and particularly the vapors including constituents boiling below approximately 500 F., tothe action of an alkylation and/or cyclization catalyst while maintaining the hydrocarbon in vapor state, whereby the olefinic hydrocarbons con-- tained in the mixture are reacted with the aromatic hydrocarbons to form side chain alkylated cyclic and aromatic compounds, and further aromatic formation from unsaturates takes phosphorus pentoxicie, aluminum chloride, barium chloride, boron halide, the lower oxidesor sulfides of chromium, cobalt, molybdenum,

uranium and tungsten, and a silica gel reaction product with phosphoric acid. The catalytic reaction, is preferably carried out at a temperature of approximately 700 F. and at a pressure of approximately 50 to 200 lbs. per square inch.

Other. features, objects and advantages of the 6 improved process of the present invention will be apparent to those skilled in the art from the following more detailed description thereof, taken in connection with the accompanying drawings in which:

Fig. 1 is a more or less conventional diagrammatic elevational view of assembled apparatus elements particularly adapted for carrying out the improved process.

Fig. 2 is a view similar to Fig. 1 showing a modification of apparatus for carrying out a modified form of the improvedprocess of the present, invention.

Fig. 3 is an enlarged broken sectional view illustrating a form of rotary valve structure shown in Fig. 2 of the drawings. 4 I

Referring to Fig. 1 of the drawings, the crude hydrocarbon to be'used for the manufacture of aromatic hydrocarbons in accordance with the process of the present invention, is introduced into the apparatus under pressure by means of a pump (not shown) through a line 2, and preferably passed through a plurality of heating tube banks 4, 6, 8 and i mounted in a pipe still furnace 12 which may be of usual and well-known type and structure. The oil stock in passing through the tube banks'4 and 6 is preferably heated to a temperature from about 920 to 950 F. and thereafter heated in the tube banks 8 and I0 to a temperature of. from 980 to about 1020 F. at which temperature the highly heated products are discharged through a transfer line it into the lower portion of an enlarged vertical reaction chamber E6.

The tube banks 8 and ill, or tube bank", is preferably of sufficient length to give a substantial period of reaction time for breaking up and converting substantial proportions of the hydrocarbons into products boiling below 450 F. The highly heated products discharged into the reaction chamber ii are subjected to a relatively long time soaking reaction which is preferably exo-- thermic in nature, so that the temperature actually rises in the chamber to a point of from 1000 to 1070 F. at the top of'the chamber where the vapors are discharged through a line is. Some of the exothermic reaction may take place in the tube bank l0 andds continued in the chamber l6 which is preferably heavily insulated. By the time the conversion products reach the top of the chamber it, they preferably contain approximate-' ly 35% of aromatic hydrocarbons and 45% of olefinic hydrocarbons in the fraction boiling below temperatures of from 400 to 450 F. Such a fraction suitable for subsequent catalytic conversion may contain from approximately 35% to approximately 55% of oleflnic hydrocarbons and from approximately 30% to approximately 45% of aromatic hydrocarbons.

As the highly heated hydrocarbons discharge through the line It, their temperature is preferably reduced instantaneously to a point within the range of approximately 600 to 800 F. by introducing into the discharging vapors a fluid cooling medium from a valved line 20. The resulting mixture passes on through a valved line 22 into a vapor separator 24 where any condensed or unvaporized materials are separated from the hydrocarbon vapors.

In carrying out the reaction in the chamber i8, 7

some free carbon of the nature of carbon black is usually formed in the reaction chamber. Where this occurs, it may be readily blown from the chamber through a valved line 28. During the operation the liquid collected in the vapor separator 24 is preferably withdrawn through a valved line 20 into a flash still 20, where vaporization of readily vaporizable constituents is effected by reduction in pressure. The unvaporized material is discharged from the still 20 as fuel oil through a valved line 32 while the vapors are conducted through valved lines 34 and 88, a condenser 38, and a line 40, into a receiver 42. The condensate collected in receiver 42 may be used as the cooling fluid for cooling the vapors discharging through line l8, by withdrawing the condensate through the valved line 20 which is provided with a pump mounted therein. Any gas separated out in receiver 42 may be released through a valved line, and any excess condensate may be discharged through a valved line 48. Instead of vaporizing the liquid collected in the separator 24, it may be passed directly through lines 28, 38, the cooler 38, and the line 40, into the receiver 42, and reused as the cooling medium by forcingdt again through .the lin 20, excess liquid being withdrawn through the valved line 46.

The vapors separated out in the separator 24,

- and including the gas produced in the conversion adapted to efiect the alkylation of the aromatic hydrocarbons contained in the mixture of vapors, as well as dehydrogenation and cyclization of oleflns. 'The aromatic hydrocarbons are alkylated bythe gaseous oleflnic hydrocarbons as well as by some parafiinic hydrocarbons, due to the influence of the catalyst, so that side chain aromatic compounds are produced. The aromatic hydrocarbons in the vapors in the line 48 comprise benzene derivatives which may contain some side chains. The alkylation may alkylate at one or more positions in the benzene ring, so that a variety of side chain benzene and cyclic hydrocarbon derivatives are formed.

Dehydrogenation and cyclization of oleflnes containing six or more carbon atoms also occurs and the hydrogen will normally be consumed as prise one of the catalytic materials referred to above, deposited for example, on clay or some inert carrier material supported in the chamber 50. The reaction is preferably carried out at relatively low temperatures, for example. of the order of from 600 to 800 F. and preferably-while the" vapors introduced through the line 40 are continuously maintained in the vapor state. The catalyzed reaction products from chamber 50 are withdrawn through a line 52 in which the products may be cooled, if desired, by introducing a tion is' desired at the bottom of fractionating tower 82. In any case the products conducted through the line 52 may be discharged directly into avapor separator 58 for the separation of any bons of lower boiling point produced by the process. If desired, the separator 58 may be entirely omitted and the vapors from the chamber 50 passed directly into the tower 82.

In the tower 62 the vapors are subjected to rectifying conditions, so that a rectified higher boiling product is obtained at the bottom of the tower and withdrawn through a valved line 84, and an overhead vapor fraction is obtained which is withdrawn through a valved line 86, subjected to mounted therein, and then conducted into a receiverm. The vapor separator 56 may be omitted if the lower portion oi the tower 62 is used to remove the heavier polymers, and the light colored reflux is removed as a side stream through line 78. Any of the unreacted gases produced by the process pass with the vapors from the tower 62 and are eventually separated out in the receiver it. These gases, comprised primarily of saturated hydrocarbons, such as methane, ethane and propane, are discharged through an automatic pressure valve controlled line 12. In carrying out the rectification in the tower 62, a suitable reflux ratio is maintained therein by returning condensate from the receiver 10 through a line H by means of a pump mounted therein, so as to produce a distillate boiling preferably below 450 F. The overhead product produced by the rectification is withdrawn from the receiver 10 through a valved line 16, and if desired. an intermediate product may be produced on the 'tower and withdrawn from any desired level therein as a side stream, as for example, through a valved line 18.

The product removed through the line it is ordinarily passed to a stabilizer (not shown) and may have a boiling range of from about'10.

F. to 350 F. or 400 F.. and that withdrawn through the line 8%, a boiling range of from 425 to about 550 F.

The improved process of the present invention may be carried out in slightly modified manne? by utilizing the apparatus shown in Figs. 2 and 3 of the drawings, which apparatus includes certain elements which are identical with those used in Fig. 1. In describing the process in connection with Fig. 2, therefore, the apparatus elements which are the same as those shown in Fig. 1 will be referred to by the same referenc characters.

In accordance with the modification of the process shown in Fig. 2, the oil to be converted is subjected to substantially the same treatment in the furnace i2 as that described in connection condensing conditions in a condenser 68.

of the reaction products boiling below approximately 450 F. The exact temperature and pressure conditions necessary for securing 'approximately this conversion for any particular stock are readily determinable by conducting an exp rimental operation on any given cracking furnace and reaction coil. and correlating the gravity of the product with its hydrocarbon analysis.

The highly heated reaction products resulting from the treatment in the coil 80 are conducted through a line 82 into a line 22 in which the temperature of the products is suddenly reduced to a point below coke deposition in the line by introducing a. cooling fluid into the vapor stream from suiting liquid removed and treated in the same with Fig. 1, the oil being introduced through the pipe 2 and passed in series through the tube banks 6, 8. 8 and II]. In the modified process, however, the products discharged through the transfer line it at a temperature of from 980 to 1020 F. and at a pressure of approximately 250 lbs. per square inch, are conducted through a reaction coil 80 mounted in a temperature controlled chamber in which the temperature is controlled by supplying suitable tempering hot gases, for example, from thefurnace i2. to maintain the temperature, or not permit it to rise above approximately 1070" F. at the outlet. In the formation of aromatic hydrocarbons in the tube bank I0 and reaction coil 80, sufllcient time is permitted to secure approximately 45% of oleflnic and 35% of aromatic hydrocarbons in the condensate'portion gianner as that described in connection with The, vapors separated in the separator 26 of Fig. 2 and comprising constituents boiling up to a temperature of about 750 F., including any normally gaseous constituents formed by the conversion reactions carried out in the furnace i2 and coil 80, are conducted through a line 86 to a catalytic reaction zone comprising a coil 86. A finely divided catalyst such as one of the catalysts referred to above, which may be deposited on a solid carrier and contained in a supply bin 89, is permitted to flow through a valved line 90 in which is mounted a rotary feed and measuring valve 92. This material is discharged at a controlled rate into the stream of vapors passing through the line 88 and carried through the reaction coil 86.

The rotary valve or may be of any suitable type commonly used for feeding solids at a controlled rate. For example, this valve may comprise a rotary plug 86 provided with a pocket 96 for receiving the catalytic material from the bin 88 through the line 90. At every rotation of the plug 94, the material deposited in the pocket 95, while in the position shown in Fig. 3, is discharged through the lower portion of the line 90 into the vapors in the line 86. The valve is preferably vapor-tight and provided with a valved vent line 98 so that any vapor picked up by the pocket 96 from the lower portion of line 90 will be vented through the line 98 without disturbing the material flowing under atmospheric pressure through the upper portion of the line 90.- For more uniform distribution of catalyst in the vapor stream, the plug preferably contain'sa about'700 F. and held at this temperature in the taining the suspended catalytic material are discharged from the reaction coil 80 through a line ill into s, cyclone separator III which may be oi any usual form, but adapted to withstand relatively high pressures, and in which the suspended solid catalytic material is separated. The solid catalyst is removed from the cyclone separator through a valved line ill in which is mounted a rotary valve I which may be of submntially identical structure to that of the valve If.

The cyclone separator III is preferably heavily insulated so that no condensation is permitted. The separated vapors are discharged from this cyclone separator through a line 52 and thereafter handled in' the same manner as that described in connection with Fig. l of the drawings. The catalytic material discharged through the line I may be reviviiied and reused by returning it to the bin or hopper II. In the form of operation described in connection with Fig. 1, two or more catalyst chambers I. may be used alternately, so that theone cut of the system may be connected to certain equipment for revivifying the catalyst, after which the chamber may be cut back into the system and reused. In carrying out the improved process, the va pors and gases conducted from the separator I normally contain. a major portion of hydrocarbons boiling below approximately 400 1'. which is removed as an overhead product from the tower 62 since the aromatic hydrocarbons boiling within this range, after alkylation'by the catalytic reaction, have the widest held of utility. For example, the alkylated benzene derivatives containing one or more side chains of from 1 to 4 carbon atoms, are particularly desirable for use as blending agents for increasing the anti-knock value of motor fuels. However, the vapor products discharged from theseparator fl also include higher boiling hydrocarbons which will include aromatic and cyclic compounds of a more complex nature than the simple benzene derivatives, i. e. naphthalene and anthracene derivatives. Such compounds after being alblated, are valuable for use as intermediates in the manufacture of dyes and for many other purposes.

The products produced in accordance with the improved process of the present invention by the catalytic reaction, are preferably fractionated into rather narrow fractions and in some cases by close fractionation, so that individual aromatic hydrocarbons may be recovered for particular purposes. The fractionation operation may be controlled so that a product boiling within the range suitable for motor fuel, is withdrawn through the line 16. When the operation has been carried out so that approximately 45% of oleilnic and 35% of aromatic hydrocarbons is contained in the condensable portion of the vapor stream boiling below 400' F;, removed from the separator 24, the .product boiling below approximately 400 F. and removed through the line 18 will contain approximately 85% of aromatic hydrocarbons comprised primarily of benzene derivatives containing one or more side chains.

A specific example of a typical operation in which a light straight run gas oil is introduced into the apparatus through the line 2, and subjectedto the improved process is as follows:

Light gas oil is heated in the furnace ii to a discharge temperature of 985 F. These vapors are then conducted to an enlarged reaction chamber at 225 pounds pressure such as the chamber It, where an exothermic reaction of intermediate degree is permitted to take place, the vapors being discharged from the chamber at a temperature of 1025' It, and instantaneously cooled to Y 16 7 86 of from 87 F. to 405' E, contains 83% or aromatic hydrocarbons as determined by the Egloff and Morrell method (Industrial 8: Engineering Chemistry, vol. 18 (1926) 9 8,88 354-356).

The heavy material removed from the bottom of go the tower comprises approximately 10% of the original charging stock, while the product collected overhead, as referred to above, comprises approximately 50% or the original charging stock to the furnace.

The gas loss on the whole operation is about -20% as compared to from to 40% gas loss previously encountered in the manufacture of products containing high percentages of arcmatic compounds.

30 From the foregoing description, it is apparent that various modifications and alterations may be made in the process without departing from the spirit and scope of the invention, as defined by the accompanying claims. Having thus described the invention in its preferred form, what is claimed as new is:

1. The process 01' manufacturing side chain cyclic and armatic hydrocarbons from petroleum oil distillates of substantially paraflinic character, which comprises passing the petroleum distillate charging stock through a heating zone in a confined stream of restricted cross-section and therein heating the distillate to a temperature of from 950 to 1020" r2, thereafter subjecting the heated distillate to an exothermic reaction at a high temperature for a substantial period of tim during which the distillate is converted into a reaction mixture containing a substantial proportion of condensable products boiling below 400' F., said proportion containing from approximately 35% to approximately of oleflnic hydrocarbons and from approximately 30% to approximately 55% of aromatic hydrocarbons, cooling the resulting mixture of conversion products to condense high 55 boiling components thereof, but insufliclently to condense the constituents boiling up to approximately 500 F., separating the condensed materials'from the resulting vapors and gases and passing the latter directly into a catalytic reac- 00 tion zone in intimate contact with a solid alkyiatiOn and cyclization catalyst, maintaining a reaction' temperature upwards of about 600 F. in said catalytic reaction zone which is sufficient to convert the vapors and gases into the desired (is cyclic and aromatic hydrocarbons, and fractionating the resulting reaction products to recover the desired hydrocarbons therefrom.

2. In the process of manufacturing side chain cyclic and aromatic hydrocarbons in which an 7 olefinic, cyclic and aromatic hydrocarbon stock is subjected to alkylation conditions in the presence of an alkylation catalyst, the improvement which comprises preparing a hydrocarbon stock for alkylation by cracking a mineral oil distillate at a temperature of from 950 to 1020 I". under conversion conditions adapted to produce a substantial proportion of condensable material bolling below a temperature of from 400 to 450 F., said material containing from approximately 35% to approximately 55% of olefinic hydrocarbons and from approximately 30% to approximately 45% of cyclic and aromatic hydrocarbons, subjecting the highly heated products of the cracking operation to cooling sufiicient to condense constituents boiling above about 500 F. and leave a vapor fraction including said condensable material and the normally gaseous hydrocarbons produced by the cracking operation, separating said vapor fraction from said condensed constituents as said hydrocarbon stock, and passing said vapor fraction while hot directly into an alkylation zone in intimate contact with a solid alkylation catalyst at a temperature of from 600 to 800 F. to produce said side chain cyclic and aromatic hydrocarbons.

3. In the process of manufacturing side chain aromatic hydrocarbons in which a stock comprised of olefinic and aromatic hydrocarbons is subjected to alkylation conditions in the presence of an alkylation catalyst, the improvement which comprises preparing the hydrocarbon stock for alkylation by cracking a mineraloil distillate at a temperature of from 950 to 1020" F.'under conversion conditions adaptedto, produce a substantial proportion of condensable material boiling below a temperature of from 400 to 450 F., said material containing at least 30% each of olefinic hydrocarbons and aromatic hydrocarbons; subjecting the highly heated products of the cracking operation to cooling sufilcient to condense constituents boiling above about 500 F. and leave a vapor fraction including said condensable material and the normally gaseous hydrocarbons produced by the cracking operation,

separating said vapor fraction from said condensed constituents as said hydrocarbon stock, and passing said vapor fraction while hot directly into an alkylation zone in intimate contact with a solid alkylation catalyst at a temperture of from 600 to 800 F. to produce said side chain aromatic hydrocarbons.

4. In the process of manufacturing side chain cyclic hydrocarbons and aromatic hydrocarbons in which a stock comprised of olefinic and aromatic hydrocarbons is subjected to alkylation and aromatization conditions in the presence of an alkylation and aromatization catalyst, the improvement which comprises preparing the hydrocarbon stock for the operation by cracking a mineral oil distillate at a temperature of from 950 to 1020 F. under conversion conditions including an aromatic-forming exothermic reaction, stopping the exothermic reaction when the condensable material in the reaction product boiling below a temperature of from 400 to 450 F. contains approximately but not more than approximately 35% of aromatic hydrocarbons, subjecting the heated products of the cracking operation to cooling sufficient to condense constituents boiling above about 500 F. and leave a vapor fraction including said condensable material and the normally gaseous hydrocarbons produced by the cracking operation, separating said vapor fraction from said condensed constituents as said hydrocarbon stock, and passing said vapor fraction while hot directly into a reaction zone in intimate contact with a solid alkylation and aromatization catalyst at a temperature upwards of about 600 F. to produce said side chain cyclic hydrocarbons and aromatic hydrocarbons and to substantially increase the quantity of aromatic hydrocarbons over the quantity contained in said stock.

WILLIAM KAPLAN.

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