US2098045A - Treatment of hydrocarbons - Google Patents

Description

Patented Nov. 2, 193? PATENT GFFIC TREATMENT OF HYDROCARBONS Vladimir Ipatiefi and Vasili Komarewsky, Chicago, 111., assignors to Universal vOil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application July 18, 1935,

. Serial No; 32,036 r 6 Claims. (Cl. 260-168)- This inventionrelates more particularly to a process for the manufacture of derivatives of aromatic hydrocarbons, particularly those formed by replacing ring hydrogen atoms with aliphatic hydrocarbon radicals.

The value of the various aromatic hydrocarbons as bases for the manufacture of chemical derivatives is well known. They serve as a starting point for the manufacture of a large number of dyestuffs, explosives-disinfectants, solvents, fuels, etc. By successively replacing the ring hydrogen atoms with methyl and other aliphatic residues, the homologs of benzol are produced.

In the production of aromatics by the destructive distillation of coal or other hydrocarbon, mixtures such as those constituting the various fractions of petroleum, there are normally produced in the mono-nuclear series preponderating yields of benzol and its closely-related homologs such as toluol and the xylols, these latter being the mono and di methyl derivatives of benzol respectively. There is practically no production of homologs containing aliphaticresidues of higher molecular weight such as, for example,

ethyl benzol, propyl benzol, etc. While the present process may be employed to produce anyalkyl derivative of benzol including the methyl derivatives, it is particularly applicable to theproduction of the higher alkyl derivatives.

To briefly review the alkylation art with the 4,5 Ethylene Ethyl suliuric acid (2) CsHe+H2SO4=CsH5SO3H+H2O I Benzol Benzol sulionic acid Ethyl benzol By substituting other olefins or mixtures of olefins for the ethylene shown in the equation it is possible to more or less efliciently produce a large number of alkylated derivatives of benzol. The efiiciency of reactions of the above character is limited to .a considerable extent by the tendency of the sulfuric acid to polymerize 5 the olefins rather than add them to the aromatic nucleus and also that it has a definite tendency to oxidize all the hydrocarbons involved and produce undesirable by-products, these being sometimes of a heavy tarry character. 10

It is also known in the. art to employ metal halides such as for example, aluminum chloride and its more or less equivalent materials to effect reactions of the above general character.

These types of catalysts tend to foster polymerl5 izing reactions among olefins to a great extent and also tend to form sludges consisting of compounds formed by the direct addition of olefins and the chlorides which are dificult to decompose for the regeneration of the catalyst. 20 There is also a considerable tendency to carbonization if elevated temperatures are employed and the reactions are diflicult to control in the sense that if, for example, a. mono alkyl derivative is desired there are concurrently 25 formed di and tri and even higher derivatives corresponding to a certain equilibrium.

In one specific embodiment the present invention comprises the manufacture of alkyl den rivativesof aromatic hydrocarbons by treatment 30 with parafiin hydrocarbons in the presence of phosphoric acid at elevated temperatures of from about 700 Futo about 900 F.

The alkyl derivatives thus formed may be used for increasing the antiknock value of gasoline motor, fuels by blending, as well as for the preparation of pure alkylated products.

In the operation of the process, an aromatic and a paraffin are heated in the presence of approximately 10% by weight of a phosphoric acid, orthophosphoric acid (H3PO4) of about 90% concentration being generally utilizable. when the parafiin employed is liquid such as, for example, hexane, the mixture of hydrocarbons in the proportions necessary for producing best yields of the desired alkylated product is maintained in agitation with the acid in exteriorly heated rotating bombs or the hydrocarbons and acid may be pumped through tubular heating elements to allow continuous operation, reliance being placed upon the turbulence produced in the heating coil to assure effective contact.

If an aromatic is to be alkylated with a normally gaseous paramn such, as, for example, butane or lower, the gas may be pumped under ,these types of industrial operations.

pressure into a bomb containing the aromatic and the phosphoric acid, whereupon the bomb is heated and shaken until the alkylation reac-. tions are completed. As before in the case of liquid paraflins, reactions may be brought about between normally gaseous paraflins and liquid aromatics in continuous tubular heating elements by injecting the gaseous/paraffin into the continuously flowing in towers filled with-relatively inert fragmentary material such as crushed silica in order to insure effective contact.

The temperature and pressure conditions under which alkylation reactions occur will vary with each combination of aromatic and parafiirr which may be employed and with the amount of phosphoric acid used. In the case of lower boiling normally liquid parafflns typified by hexane, when 'these are used to alkylate the lower boiling aromatics such as benzol, toluol and the xylols. temperatures in the neighborhood of 800 to 900 F. are commonly suitable. In the case of batch operation in pressure vessels the pressure may rise' as high as atmospheres at the operating temperature, and owing to the formation of some fixed gases as a result of side reactions there will ordinarily be some residual gas pressure when the bomb is cooled to atmospheric temperature.

The type of reactions which occur in the present process is sharply differentiated from those which employ olefins to alkylate aromatics and produce their-higher homologs. In the present instance the parafilns undergo decomposition in the presence of phosphoric acid to form active radicals which then unite with the aromatics to form the desired alkyl derivatives. In the absence of other groups of hydrocarbons the simpler aromatics or no olefins. In the case of cracked gases the olefins may be removed by absorption in acids or in more generally known alkylation reactions and the residual gases then employed to alkylate further amounts of aromatics in thepresence of the phosphoric acid catalyst by-methods already Ethane Ethylene Toluene Methyl ethyl benzol The above reactions are suggestive of the stepswhich occur and which result in the formation of the alkylated products though it is not intended to infer that they offer a complete explanation of the observed facts.

. The following example will serve to illustrate the nature of the reactions involved and the results obtainable by the use of the process although the scope of the invention is not limited by the specific data given.

Benzene and hexane were heated in a rotary pressure vessel at 832 F. (450 C.) for 20 hours in the presence of 89% phosphoric acid. Three runs were made. The results are tabulated as follows:

' Maxil Phos- Hrs. Final Benzene Hexane mum Liquid Run No. phoric on press.

chgd. chgd. acid mu @pggig 0 recovery Pu. 511 Pb. by Pie. by (Aim) (Atm.) Pie. by wt. wt. wt. wt.

are unaffected by phosphoric acid under the preferred conditions of operation. In a sense the reactions involved may be looked upon as coming under the definition of condensation reactions since there is elimination of some hydrogen and the formation of lower boiling paramns, as will be shown in later examples.

-The process thus utilizes normally unreactive parafllns to combine with and alkylate aromatics. Its practical utility appears in that various parafflns and mixtures of paraflins may be employed instead of the more reactive olefins. For example, instead of utilizing the olefinsin cracked hydrocarbon gas mixtures for alkylation of aromatics, (the olefins normally constituting only minor percentages ofthe total gas mixture) naturally occurring paraflin gases. may .be employed or straight run gasoline fractions containing little The liquid composite was submitted to a frac- 121011.81 distillation.

Boiling point B I R romine Percent number 30 0. "0. F.

1 57-07v -152 12 8 1. 4204 2 67-71 152-100 18. 0 7 l. 4242 3 71-81 160-178 20. 5 3 Y 1. 4394 4 81-83 178-181 9. 0 2 1. 4578 5 83-91 181-196 8. 0 2 1. 4650 0 91-101 196-214 6. 0 3 1. 4793 7 101-115 214-239 4. 0 3 1. 4850 8 115-150 239-302 3. 5 5 1. 4843 9.- -160 302-320 4. 5 .4 1. 4862 10.- -170 320-338 0.0 4 1. 4881 11,- -190 338-374 3. 5 4 1. 4920 12.- -220 374-428 2.0 7 1. 4998 13.. 220-245 428-473 1. 5 9 1'. 5249 14.- Bottoms 1. 5

- zene charged; some of the benzene being recovered. This raises the amount of alkylated benzene to above 35%.

It will be seen. that practically all of the materials formed boil within the range of commercial gasoline specifications. Tests showed that the composite liquid was of unusually high anti-knock value of the order of that shown by iso-octane used as a standard of reference in rating motor fuels by the engine test.

The novel and useful character of the-invention is evident from the preceding specification and single instance of numerical dataintroduced but neither is to be considered as imposing undue limitations upon its generally broad scope.

We claim as our invention:

1. A process for the alkylation of aromatic hydrocarbons to produce more valuable products therefrom, which comprises subjecting a mixture comprising said aromatic hydrocarbons and paraffinic hydrocarbons to the action of an acid of phosphorus at an alkylati ng temperature between approximately 700 F. and 900 F. where by the parafiinic hydrocarbons undergo decomposition, the products of which decomposition combine with said aromatic hydrocarbon to alkylate same, and recovering the alkyl derivatives thus formed.

2. A process for the alkylation of aromatic hydrocarbons to produce more valuable products therefrom, which comprises subjecting a mixture comprising said aromatic hydrocarbons and paramnic hydrocarbons to the action of a phosphoric acid catalyst at an alkylati-ng temperature between approximately 700 F. and 900 F. whereby the paraflinic hydrocarbons undergo decomposition, theproducts of which decomposition combine with said aromatic hydrocarbon to alkylate same, and recovering the allwl derivatives thus formed.

3. A process such as claimed in claim 1 characterized in that the process is carried out at a pressure between atmospheric and approximately 100 atmospheres.

4. A process such as claimed in claim 1 wherein the paraflinic hydrocarbons are gaseous.

5. A process for the alkylation of aromatic hydrocarbons which comprises subjecting the aromatic in the presence ofa paraflinic hydrocarbon to the action of a phosphoric acid at a temperature between approximately 700 F. and 900 F. and under superatmospheric pressure, and recovering the alkyl derivative thus formed.

6. A process for the alkylation of aromatic hydrocarbons of the benzene series which comprises subjecting the aromatic in the presence of a paraflinic hydrocarbon to the action of a phosphoric acid at a temperature between approxi mately 700 F. and 900 F.

. VLADIMIR IPATIEFF.

V'ASILI KOMAREWSKY.