US2347790A - Alkylation process - Google Patents

Description

Patented May 2, 1944 ALKYLATION PROCESS Arlie A. OKeliy, Woodbury, N. J., and Dale P. J.

Goldsmith, Cambridge, Mass, assignors to Socony-Vacnum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application March 15, 1940,

Serial No. 324,085

17 Claims. ('01. zed-683.4)

By proper selection of the paraflins and olefines,

motor fuels may be syntheticaily built-up which are composed of isooctanes or paraflinic compounds which approximate isooctanes in structure and thereby yield high grade motor fuels such as aviation grade. For this reason and the fact suitable gaseous starting materials are a byproduct of the industry, there has been considerable activity along these lines in the last few years. As a result of the activity several processes have been suggested. For instance, Morreli U. S. P. 2,169,809 discloses a low temperature process for alkylating isoparaffins with oleiines using sulfuric acid as a catalyst and keeping the temperature between about -10 and +20 C.

Again Ipatieii' et ai. U. S. P. 2,112,847 disclose an alkylation process for isoparafilns and olefines using aluminum chloride in combination with hydrogen chloride as a catalyst and keeping the temperature at or below 0 C. In these catalytic processes only isoparafflns are alkylated, normal paraflins being unaffected. It has also been proposed to alkylate paraifins with olefines at high temperatures. However, such latter proposals have usually been concerned with non-catalytic processes, for example, Frey, U. S. P. 2,002,394 discloses that paraflins and olefines may be joined thermally at high temperatures and pressures.

It is an object of our invention to provide a high temperature catalytic alkylation process for alkylating parafiin hydrocarbons with oleiine hydrocarbons.

A more specific object of our invention is to provide a process for the production of a high grade motor fuel by alkylatingsuitable parailins with suitable oleflnes.

A most important object of our invention is to provide a process for alkylating parafllns with 'oleflnes which will alkylate normal paraflins in substantial amounts.

Our invention comprises alkylating paraflinic hydrocarbons which may be either normal or iso-paraflins or both with olefinic hydrocarbons at relatively high temperatures and pressures in the presence of certain catalysts.

The catalysts which we have discovered may be used in our invention are the metal chlorides and fluorides which are solid, stable compounds under the conditions of our process. It appears all such truly solid, stable metal chlorides and fluorides are operative. We, at present, particularly prefer such chlorides and fluorides of the metals of group II of the periodic table, and of these preferred catalysts we especially prefer catalysts consisting of or containing alkaline earth chlorides or fluorides. Our catalysts may be either a singlepure compound, e. g., Cal or CaClz; a mixture of our fluorides or chlorides or both, e.,g., Cali; plus Mgr-z or CaCli plus BaCl: or CaFc 'plus CaClz; or the catalyst may comprise metal fluorides or chlorides which are complexes or double salts of two fluorides, chlorides or both, e. g., CaFaBaF: or ZnF'z.CaFz or activated cryolite. In practice when employing complex or double salts, we usually use salts which are equimolecular in concentration; however, our experiments indicate that variation of one component makes no difference in the results obtained. Accordingly, in th claims where we. use the term associations we mean to include both mixtures and compounds.

It is important to note that in the case of the metal fluoride catalysts, the conventional fluoride products obtained in commerce, except fluorspar, were generally found not to be particularly active compared to the chlorides. However the relatively inactive fluorides may be activated so that their activity is of the nature of the fluorspar and is, in general, higher than the activity of the chlorides. Activation of the relatively inactive fluoride catalysts may be accomplished, for example, by re-precipitation whereby the catalyst is produced largely in a much greater degree of subdivision than when'commercially prepared.

The re-precipitated catalysts thus present, if not a different, at least more active surface of contact. This, activation of the fluorides by re-precipitation may be carried out, for instance, by precipitating such fluorides in dilute solution by 'means of sodium fluoride, drying the precipitated fluoride and then igniting it at temperatures up to about 500 0. Again activation of the complex fluoride, cryolite (AlFa.3NaF), may be accomplished, for example, by digesting same in powder form with dilute hydrochloric acid or the like to remove a part of the sodium fluoride. This latter activation may be somewhat analogous to activation of clays by acids. Removal of some sodium fluoride may leave a more active surface or may leave more active surface or both.

The chloride and fluoride catalysts or our invention may be used by themselves in suitable form, e. g.-, granularQor, if desired or necessary.

these catalysts may be supported by suitable inert or relatively inactive carriers of a refractory nature in order to assure proper contact of the hydrocarbon gases with the catalysts in the catalytic chamber. Typical examples 'of refractory carriers suitable for use with our catalysts in the present invention comprise ordinary cryolite, clay, alumina, magnesium oxide, bauxite and zinc oxide. It is to be understood that when we use the term catalyst herein, we mean the actual catalytic material, viz., the chlorides or fluorides, and not the composite mass of our catalysts with refractory carriers.

The amount or proportion of our catalysts that may be used can vary over rather wide limits. In most of our operations we prefer to employ aroundt 25% to around 50% by weight with respect to the hydrocarbon charge. However amounts of 100% or even more may be used, if desired. Accordingly, it is to be understood the invention is not restricted to these amounts which are stated for illustrative purposes but rather to the general use of the catalysts to give our improved results.

In carrying out our process, We prefer, for

Practical operations, to use temperatures between about 000 F. and about 1000 F., although higher temperatures may be used if adequate pressures are provided, and we particularly prefor temperatures between about 800 F. and about 1000 F. The pressures at which our process is conducted should be upwards of about 2000 lbs. per sq. in., the most suitable pressure being more or less dependent upon the particular hydrocarbons and temperature involved. For instance, as it is more difiicult to .react the propyl radicals than higher radicals, the pressure should not be below about 3000 to 3500 lbs. for alkylating propane with propylene, and, in fact, for temperatures of 800 F. to 1000 F. we prefer to use pressures of 3000 lbs. or more for all alkylationse In general the higher the pressure the better the result. For most practical operations at the present time a pressure between about 2000 and about 5000 lbs. per sq. in, will be found to be suitable. However higher pressures may be used, for example, up to say 20,000 lbs. .per sq. in, the upper limit on pressure bein dictated merely by the feasibility of maintaining such pressure.

An important feature of the present invention is the fact that, contrary to many prior catalytic processes which are only capable of alkylating isoparafiins, our process is capable of alkylating normal paramns in substantial amounts, and, in fact, normal paraflins are alkylated more emciently by our process than are isoparaffins. Accordingly while the prior art has known highly eihcient catalytic processes for alkylating isoparafilns, our process furnishes for the first time a highly efficient catalytic process for alkylating normal parafiins. The alkylation is more effective when using isoolefines, however normal olefines may be used. It is also to' be understood that while the process is particularly outstanding for the alkylation of normal pa afins, the process is not limited thereto since isoparafiins are also efiiciently alkylated by the process.

The paraflins and olefins to be used in our process may be derived from any suitable source bilizer.

and olefines of 3 or 4 carbon atoms, namely,

butane, isobutane, propane, isobutylene, butylene, and propylene. Ethylene, however, may be used with any of the above paraillns or isoparaflins. A convenient and preferred source or these paramns and olefines is the fixed gases obtained around petroleum refineries, such as the butanebutene fraction from a cracked gasoline sta- These fixed gases of the refineries may furnish substantially all the desired pararfins and olefines or it may-be necessary or desirable to obtain additional sources, all as is well known in the art.

As pointed, out above the present process is particularly important for allrylating normal parafiins. However, there is an additional advantage in the fact that both n-parafins and isoparaffins may be alkylated by our process. Normal parafiins and isoparaffins may be, and usually are, found in admixture with each other, therefore, it is particularly noteworthy that by our process both components of the ture are alkylated rather than having one component- (n-paramn in the usual processes) go through the reaction as an inert diluent.

Furthermore it may be found desirable to combine the present process with one of the known processes for alkylating isoparafiins. Thus a paraihnic fraction containing substantial amounts of both normal and isoparaffins, such as a butane cut from a stabilizer, might be passed through a known cold sulfuric acid alkylation process whereby'substantially all the isoparafiins would be eficiently alkylated, and then the unreacted n-butane, and any other normal paraffins, could be separated out and passed through our alkylation process in order to alkylate these normal parafiins or vice versa. Suitable amounts of olefines could be added in either or both steps if, and as, needed, and likewise parafins.

In our process it is important, as in the known paramn-olefine alkylation processes, to keep the concentration of the olefines relatively low during reaction in order to eliminate as much olefine polymerization as possible. is advisable to maintain the olefine concentration in the charge below about 25% by liquid volume and preferably between about 10% and about 20% by liquid volume, and this may be done conveniently by slowly, adding the olefines to the reaction mixture.

In order to further illustrate our invention the two following specific examples are given showing the results of alkylating (1) without a catalyst and. then (2) with one of our chloride catalysts, namely, calcium chloride.

EXAMPLE I tained; 76.9% of this material boiled. below 320 an octane number of 77.2 (GER motor method) and acid heat of 92' 1'. The yield is 3.74 gallons per 1000 cu. it. oi charge per pass.

EXAllPl-III The above process was repeated except that the reaction chamber or the still was packed with will be noted that by alkylating by our process a very substantial increase in yield is obtained, and, furthermore, it will be seen that the product obtained is substantially superior.

s The following Table'I shows further results obtained in alkylating nbutane with a butylene fraction (70% oleiine) by our process under various exemplary conditions oi operation, using various suitable catalysts (see runs 14!) and how the results are superior over processes carried out under similar conditions but in the absence of 4-mesh calcium chloride, U. S. P. grade and opera catalyst (see runs 10-13) Table I T m R a Re n Reaction 0 sec on so on pressure 3" charge to m time temp. lbs/sq. in.

\ 1 gauge Pam bv volume Per cent Per cent Minutes F.

1 1,000 15 4o Anhyd. 0e01,. 30 800 3.300 2 800 15 do 850 2,650 860 I) 25 do 30 875 3,300 850 15 25 -do 30 875 3.150 sec 15 50 d0 15 900 3,250 800 15 50 do 30 900 3,350 8U) 16. 2 Anhyri. Bach. 30 875 3, 100 8(1) 16. 2 25 Anhyd. SlCh. 3O 875 3,000 850 15. 0 25 Auhyd. MgCl m 30 875 3, 200 1 000 15. 0 None N 30 800 2, 800 900 15. 0 None 30 875 3. 075 800 l5. 0 None 30 900 2, 950 900 20. 0 None 30 875 3, 175

Liquid 8p. grav Iodine num- Gallons,

Yield of Yield with product 0! cut ber of cut conversion Run No. liquid respect to boiling boiling boiling per 1,000 cu.

product oleilne below below below it. of

320 F 320 F 320 F charge Per cent Per cent 76. 6 78 o. 683 42 3.01 132 81 0. 684 40 5. 22 123. 5 80. 9 0. 687 35 6. 44 150. 0 83. 0 0.683 35 6. 02 146. 6 80. 0 0. 690 38 5. 77 166. 6 80. 0 0. 090 38 6. H3. 0 B0. 6 0. 685 38 6.08 130. 0 74. 0 0. 690 43 "l. 100. 0 86. 5 0. 685 28 4. ll 58. 6 68 0. 720 67 2. 30 100. 0 72 0. 709 56 3. 94 iii. 0 77 0. 703 57 4. 50 107. 0 77 0. 692 50 5. 59

ated at 94W 1''. A'total yield 0! normally liquid hydrocarbons of 129% with respect to the olefine used was obtained; 76.6% 01' which boiled below 320 F. The redistilled fraction boiling between 25 and 150 0., (up to 302 F), had a specific gravity of 0.685 and an iodine number of 50. The octane number by the CFR motor method was 78.7. Acid 'heat was 68 F. The yield per 1000 cu. it. 0! C4 mixtureis 5.14 gallons per pass.

Accord sly the two above examples show very clearly the advantages oi our process. Thus it 50 For purposes of still further illustrating our invention Table II is given below showing results obtained by our process under various exemplary conditions of operation using various suitable iiuoride catalysts (see runs 1-9), and how the 5 results are superior over Processes carried out Table II Catal st Reaction Volume wit Reaction Reaction ressure p in Bun N g -5g Olefin rozgect to Nature or time temp. lbs/sq. in.

i also c s Part:

p m Per on! Minutes F.

30 15 25 Flnarsper 30 875 3, 350 m 15 25 Activated cryolite. 30 875 3 300 800 15 21 Zinc cryolite 30 875 a 350 900 15 18 Fluorspar 30 850 3 500 300 15 21 Barium fluoride 30 850 3 450 800 15 21- ZnFs.C8F1.. so 875 3'325 800 15 21 canon"... 30 875 a 800 15 21 oar-ism... so 815 3'212 300 15 21 MgF, 30 875 3' 275 900 5 None None 30 875 31075 Table M-flontlnued Liquid Sp. grev. Iodine num- Gallons Volume Yield with product oi out her of cut conversion Run No. yield liquid respect to boiling boiling boiling per 1,000 cu.

product olefine below below below it. of

320 F. 320 F. 320 F. charge l by P mt P out mm: er 0 er c We claim:

1. The process of alkylating parafllnic hydrocarbons with oleflm'c hydrocarbons which comprises contacting the parafilns and olefins under alkylating conditions in the presence of an active alkylation catalyst consisting essentially of solid material selected from the group consisting of compounds of the general type MK, and associations between such compounds, wherein M is a metal and X is chlorine or fluorine and wherein MX is a metal halide that is a solid, stable compound at 800 F., and controlling the concentration of oleflns during reaction so that the principal reaction is said alkylation.

2. The process of claim 1 wherein at least a substantial portion of the paraflinic hydrocarbons which are alkylated are normal paramns.

3. The process of claim 1 wherein M is :a metal of group II of the periodic table.

4. In a process of synthesizing hydrocarbons of gasoline-boiling range by alkylating light parafilnic hydrocarbons with light olefinic hydrocarbons the improvement which comprises alkylating the light paraffins and olefins in the presence of an active alkylation catalyst consisting essentially of a member of the group consisting of alkaline earth metal chlorides and mixtures of said chlorides, and controlling the concentration of olefins during reaction so that the principal reaction is said alkylation.

5. In a process of synthesizing hydrocarbons of afinic hydrocarbons with light olefinic hydrocarfbons the improvement which comprises alkylating the parafiins and olefins at a temperature between about 600" F. and about 1000 F. and at a pressure above about 2000 pounds per square inch in the presence of an active alkylation catalyst consisting essentially of solid material selected.

of group II of the periodic table.

gasoline-boiling range by alkylating light paraiilnic hydrocarbons with light olefinic hydrocarbons the improvement which comprises allrylating the light paraiiins and olefins in the presence of an active alkylation catalyst consisting essentially' of a member of the group consisting of fluorides of metals of group II of the periodic table and mixtures of said fluorides, and controlling the concentration of olefinsduring reaction so that the principal reaction is said alkylation.

6. In a process of synthesizing hydrocarbons of gasoline-boiling range by alkylating light parafilnic hydrocarbons with light olefinic hydrocarbons the improvement which comprises allrylating the paraflins and olefins at a temperature above about 600 F. and at a pressure above about 2000 pounds per square inch in the presence of an active alkylation catalyst consisting essentially of solid material selected from the group consisting of compounds of the general type MK, and associations between such compounds, wherein M is a metal and X is chlorine or fluorine and wherein MX is a metal halide that is a solid, stable compound at 800 F., and controlling the concentration of olefins during reaction so that the principal reaction is said alkylation.

7. In a process of synthesizing hydrocarbons of gasoline-boiling range by alkylating light par- 9. The process of claim 7 wherein normal parafilns are the predominant type of parafiinic hydrocarbons which are alkylated.

10. The process of claim 7 wherein the temperature is betweenabout 800 F. and about 1000 F. and the pressure is above about 3000 pounds per square inch.

11'. In a process of synthesizing hydrocarbons of gasoline-boiling range by alkylating light paramnic hydrocarbons with light olefinic hydrocaricons the improvement which comprises alkylating the paramns and olefi'ns at a temperature between about 800 F. and about 1000 F. and at a pressure above about 3000 pounds per square inch in the presence of an active alkylation catalyst consisting essentially of a member of the group consisting of alkaline earth metal chlorides and mixtures of said chlorides, and controlling the concentration of olefins during reaction so that the principal reaction is said alkylation.

12. The process of claim 11 wherein normal parafilns are at least a substantial portion of the parafilnic hydrocarbons alkylated.

13. In a process of synthesizing hydrocarbons of gasoline-boiling range by alkylating light parafllnic hydrocarbons with light olefinic hydrocarbons the improvement which comprises alkylating the parafllns and olefins at a temperature between about 800 F. and 1000 F. and at a pressure above about 3000 pounds per square inch in the presence of an active alkylation catalyst consisting essentially of a member of the group consisting of fluorides of metals of group II of the periodic table and mixtures of said fluorides, and controlling the concentration of olefims during reaction so that the principal reaction is said alkylation.

14. The process of claim 13 wherein normal paraifins are at least a substantial portion of the parafi'lnic hydrocarbons alkylated.

15. The process of synthesizing hydrocarbons of gasoline-boiling range by aikylating light normaland iso-parafiins contained in a hydrocarbon mixture with light oleflns which comprises alkylating the predominant portion of isoparafllns of said mixture in one step where alkylation of isoparafiins with oleflns is the principal reaction and alkylating the predominant portion of normal paraiilns of said mixture in a separate step at a temperature between about 600 F. and about 1000 F. and at a pressure above about 2000 pounds per square inch in the presence or an active alkylation catalyst consisting essentially of solid material selected from the group consisting of compounds of the general type MK, and associations between such compounds, wherein M is a metal and x is chlorine or fluorine and MX is a metal halide that is a solid, stable compound at 800 F., and controlling the concentration of oleflns during reaction in said normal paraflln alkylating step so that the principal reaction in this step is said alkylation of normal paratllns.

16. The process of claim 15 wherein-M is a metal of group not the periodic table.

17. The process of claim 13, wherein the metal 10 fluoride is an activated metal fluoride.

ARLIE A. OKELLY. mm P. J. oonnsm'rn.