US2441962A - Production of long-chain olefins by catalytic cracking of paraffinic wax - Google Patents

Description

Patented May 25, 1948 PRODUCTION F LONG-CHAIN OLEFINS BY CATALYTIC CRACKING 0F PARAFFINIC WAX 'William'I. Gilbert, New Remington, and Charles W. Montgomery, Oakmont, ,Pa minors to Gulf Research 8a Development Companmlitts burgh, Pa., a corporation oi Delaware No Drawing. Application June 22, 1945,

Serial No. 601,071

This invention relates to a method of catalytic cracking and more particularly it relates to the catalytic cracking of parafllnic wax to oleflns.

Olefins in the molecular weight range above. gasoline, particularly if they are of straight chain structure, are highly desirable for use in the synthesis of special lubricants, rust inhibitors, and many other materials. Such oleflns have been obtained prior to the present invention at relatively high cost from natural products. Cracking processes, both thermal and catalytic, have long been applied to'hydrocarbons including parafilnic vide 'an improved catalytic cracking process for the conversion of paraflinic waxes to olefins in the C1: to C20 range.

These and other objects are attained by the present invention wherein parafilnic waxes are subjected to cracking conditions in the presence of a catalyst comprising a hydrated magnesium silicate-calcium silicate compound. By the use of this catalyst it is possible to obtain a high yield of olefins in the Cu to Can range composed predominantly of straight chain molecules.

The data in the table below summarize examples of runs in which 135 F. E. M. P. ASTM melting point parafflnic wax having an average molecular weight of 399 was charged at atmospheric pressure over granular hydrated magnesium silicate-calcium silicate compound at the temperatures and space velocities indicated in the table. The total product was then distilledat atmospheric pressure 'to 400 F. to remove the gasoline and the residue was distilled at a pressure of mm. of mercury to a cut point of 392? F. The various fractions of approximately the molecular weights shown were removed and the olefin contents determined by bromine number. The total of these fractions has been called the oil fraction.

6 Claims. (.01. 260-883) Table Run No I II III IV V-Vl Conditions:

Temperature, "F 850 815 820 845 000 Space Velocity 0.5 0.6 1.0 0. 8 0. 5 Throughput 1.0 1.0 1.0 0.8 1.0 Yields, wt. Per cent of Charge:

Gas (04 and lighter) 4.6 4. 7 3. 7 4. 5 20. l Gasoline (debut. 400 E. P.). 30.0 10.4 14.2 %.4 61. Oil Fraction (to 392 F. at

mm.) 10.6 10.0 0.2 15.5 lLIi Coke 0.2 0.3 0.2 0.2 0.17 Wax rcsigliile igrecyilele) 4B. 6 64. 7 72. 7 5:5. 4 .3

rue on Efileiency knecyde )XIOO 32. 3 d0. 0 .ti. 7 .i.i. .i 1.5. l Bromine No. oigasollne 127.7 125 131 1150.1 150.1

Br. Br. lir. lir. lir. N0. N0. N0 N0. NI).

Oil Fraction Inspection:

Out #1, init.-2l2 F. at 10 mm. 75. 3 08. 0 74. 0 70. 6 60. 0

Cut #2, 2i2-257 F. at 10 mm 7 (C14 54.4 51.7 55.6 00.5 80.4 Cut #3, 257-302 F. at 10 mm. I

l6)... 38. 7 38.1 44.1 '10. J 21.3 Cut #4, 302348 F. at 10 mm.

(G18); 20. 6 25. 2 27. 7 32. 0 12.4 Cut #5, 348-392 F t 10 mm.

(C20) 10.0 11.0 22.5 18.7 7.2 Residue 2.0 1.0 1.5 2. i 1!. 0 Per cent Olcilns:

7D 72 78 81 (i3 07 (i3 08 74 i5 54 Bit 02 00 iii) 42 '10 4'1 20 Cut #5 23 21 30 iii 13 For cent Olciins in total oil fraction. 57 51 (ill 32 mended and the temperature of 845 F. is the most preferable.

The effect of space velocity is not as pronounced as that of temperature but low space velocities decrease the olefin content of the oil, probably by hydrogen transfer, and thus a space velocity of from 0.5 to 2.0 has been found desirable and a space velocity oi 1.0 is most preferable.

- prior art ofcatalytic'cracking and the apparatus which is used may vary, many types of apparatus being adaptable to the present invention.

The catalyst is a hydrated magnesium silicatecalcium silicate compound produced by the reaction of a hot solution of a magnesium salt of a stron acid upon calcium silicate for a time sumcient to effect only a partial conversion of the calcium silicate to magnesium silicate. The catalyst is more specifically described in U. S. Patent 2,163,525 to Lyle Caldwell. It has been found most preferable to use the catalyst in a granular form;

In the specification and claims, space velocities from paraiiinic wax which comprises subjecting the paraillnic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calciuin silicate compound at a temperature in the range of 815 to 3050tE2and at a liquid space velocity in the range 4. A process for producing olefin hydrocarbons of twelve to twenty carbon atoms per molecule represent liquid volumes of reactant per volume of catalyst per hour. Throughput is the volumes of reactant per volume of catalyst before regeneration of the catalyst.

By parafilnic wax as used herein is meant pure paraflin waxes of va y ng melting point ranges as well as impure parafiinic waxes, such as crude scale wax and materials containing parafilnic wax, such as petrolatum or other waxy concentrates.

Thus we have described a new process for the production of a high yield of olefin hydrocarbons,

particularly in the C1: to C20 range by the cracking of parafllnic wax in the presence of a hydrated magnesium silicate-calcium silicate compound.

What we claim is:

1. A process for producing olefin hydrocarbons of twelve to twenty carbon atoms per molecule from parafiinic wax which comprises subjecting the parafllnic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calcium silicate compound at a temperature in the range of 815 to 900 F.

2. A process for producing olefin hydrocarbons of twelve to twenty carbon atoms per molecule from parafilnic wax which comprises subjecting the paraffinic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calcium silicate compound at a liquid space velocity in the range 0.5 to 2. a

3. A process for producing olefin hydrocarbons of twelve to twenty carbon atoms per molecule from parafllnic wax which comprises subjecting the parafilnic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calcium silicate compound at a temperature in the range of 815 to 900 F. and at a liquid space velocity in the range 0.5 to 2.0 and subsequently fractionally distilling to obtain the product boiling between 212 F. and 392 F. at a pressure of 10 mm. of mercury.

5. A process for producing olefin hydrocarbons of twelve to twenty carbon atoms per molecule from parafiinlc wax which comprises subjecting the parafiinic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calcium silicate compound at a temperature of about 845 F. and a liquid space velocity about one.

6. A process for producing a high yield of straight chain olefin hydrocarbons of 12 to 20 carbon atoms per molecule from paraffinic wax with an accompanying low coke yield, which comprises subjecting a parafilnic wax under catalytic cracking conditions to contact with a catalyst comprising a hydrated magnesium silicate-calcium silicate compound at a temperature of about 845 F., a liquid space velocity of about one and subsequently fractionally distilling to obtain the product boiling between 212 F. and 392 F. at a pressure of 10 mm. of mercury.

WILLIAM I. GILBERT. CHARLES W. MONTGOMERY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,938,088 Pungs et a1 Dec. 5, 1933 2,172,228 Van Peski Sept. 5, 1939 2,270,360 Voorhees Jan. 20, 1942; 2,278,590 Ruthrufl 1 Apr. 7, 1942 2,279,703 Bradley et al. Apr. 14, 1942 FOREIGN, PATENTS Number Country Date 596,094 Germany Apr. 12, 1934