Hydrocracking process

Abstract

A process for hydrocracking 2,4-dimethylpentane and/or 2,2,3-trimethylbutane can comprise: contacting a hydrocracking feed stream in the presence of hydrogen with a hydrocracking catalyst, wherein the hydrocracking feed stream comprises at least 0.5 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane, based upon a total weight of the hydrocracking feed stream; and wherein the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 A and a silica to alumina molar ratio of 20-75; preferably the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 A and a silica to alumina molar ratio of 20-75 and a large pore zeolite having a pore size of 6-8 A and a silica to alumina molar ratio of 10-80, wherein the hydrogenation metal is deposited on the medium pore zeolite and the large pore zeolite.

Claims

1. A process of hydrocracking at least one of 2,4-dimethylpentane and 2,2,3-trimethylbutane, comprising: contacting a hydrocracking feed stream comprising C.sub.5-C.sub.12 hydrocarbons in the presence of hydrogen with a hydrocracking catalyst under process conditions including a temperature of 425-580 C., a pressure of 300-5000 kPa gauge and a Weight Hourly Space Velocity of 0.1-30 to produce a hydrocracking product stream comprising LPG; wherein the hydrocracking feed stream comprises at least 0.5 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane, based upon a total weight of the hydrocracking feed stream; and wherein the hydrocracking catalyst comprises a hydrogenation metal in an amount of 0.010-0.30 wt % with respect to the total catalyst; and wherein the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75.

2. The process according to claim 1, wherein the total amount of 2,4-dimethylpentane and 2,2,3-trimethylbutane in the hydrocracking feed stream is at least 1.0 wt %.

3. The process according to claim 1, wherein the hydrocracking catalyst comprises 0.08 to 0.25 wt % hydrogenation metal, 15 wt % to 25 wt % alumina, and a balance being the medium pore zeolite.

4. The process according to claim 1, wherein the hydrocracking catalyst is in the form of powder and is free from a binder.

5. The process according to claim 1, wherein the silica to alumina molar ratio of the medium pore zeolite is in the range of 20-50.

6. The process according to claim 5, wherein the silica to alumina molar ratio of the medium pore zeolite is in the range of 20 to 30.

7. The process according to claim 6, wherein the silica to alumina molar ratio of the medium pore zeolite is in the range of 21 to 29.

8. The process according to claim 1, wherein a conversion of any 2,4-dimethylpentane is greater than or equal to 90%; and the conversion of any 2,2,3-trimethylbutane is greater than or equal to 90%.

9. The process according to claim 1, wherein the hydrocracking catalyst comprises at least 0.030 wt %, of the hydrogenating metal in relation to the total weight of the catalyst.

10. The process according to claim 1, wherein the hydrocracking catalyst comprises La and/or Ga.

11. The process according to claim 1, wherein the process comprises separating BTX or benzene from the hydrocracking product stream.

12. The process according to claim 1, wherein greater than or equal to 95% of the C.sub.5-C.sub.12 hydrocarbons are cracked.

13. The process according to claim 1, wherein the hydrogenating metal is at least one element selected from palladium and platinum.

14. The process according to claim 1, wherein the hydrocracking feed stream comprises benzene.

15. The process according to claim 1, wherein the hydrocracking product stream comprises a greater amount of benzene compared to the hydrocracking feed stream.

16. A process of hydrocracking at least one of 2,4-dimethylpentane and 2,2,3-trimethylbutane, comprising: contacting a hydrocracking feed stream comprising C.sub.5-C.sub.12 hydrocarbons in the presence of hydrogen with a hydrocracking catalyst under process conditions including a temperature of 425-580 C., a pressure of 300-5000 kPa gauge and a Weight Hourly Space Velocity of 0.1-30 to produce a hydrocracking product stream; wherein the hydrocracking feed stream comprises at least 0.5 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane, based upon a total weight of the hydrocracking feed stream; wherein the hydrocracking catalyst comprises a hydrogenation metal in an amount of 0.01-0.30 wt % with respect to the total catalyst; and wherein the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75 and a large pore zeolite having a pore size of 6-8 and a silica to alumina molar ratio of 10-80, wherein the hydrogenation metal is deposited on the medium pore zeolite and the large pore zeolite.

17. The process according to claim 16, wherein the zeolite in the hydrocracking catalyst comprises 75-95 wt % of the medium pore zeolite and 5-25 wt % of the large pore zeolite with respect to the total amount of the zeolite.

18. The process according to claim 16, wherein the hydrocracking catalyst has a deactivation rate of less than |3.510.sup.4 per hour|.

19. The process according to claim 16, wherein the medium pore zeolite comprises a ZSM-5.

20. The process according to claim 16, wherein the large pore zeolite comprises a mordenite.

Description

EXAMPLES

(1) Below table shows the analyzed composition of a pygas (Platfiner) stream. It can be understood that this pygas comprises essentially no amount of hydrocarbons having a boiling point close to benzene except for cyclohexane, methylcyclopentane (MCP) and 1,3-dimethylcyclopentane (1,3-DMCP). It comprises no detectable amount of 2,4-dimethylpentane (BP 80 C.) or 2,2,3-trimethylbutane (BP 81 C.).

(2) Pygas Composition (Platfiner)

(3) TABLE-US-00001 Component C Number BP, C. wt % butane 4 1 0.02 methylbutane 5 27.7 0.34 pentane 5 36.1 0.39 2-methylpentane 6 60 3.93 3 methylpentane 6 63 2.58 hexane 6 68 7.59 methylcyclopentane 6 72 7.98 benzene 6 80.1 47.87 cyclohexane 6 80.7 3.24 trans 1,3-dimethylcyclopentane 7 91 0.47 1,3-dimethylcyclopentane 7 92 1.15 2,2,4-trimethylpentane 7 98 0.37 heptane 7 98 0.80 methylcyclohexane 7 101 0.57 ethylcyclopentane 7 103 0.66 toluene 7 111 13.59 octane 8 126 0.05 ethylbenzene 8 136 3.07 m/p-xylene 8 139/140 1.41 o-xylene 8 144 0.44 nonane 9 151 0.05 iso propyl benzene 9 152 0.04 propyl benzene 9 159 0.01 1-methyl-(3&4)-ethylbenzene 9 152 0.06 1,3,5-trimethylbenzene 9 163-166 0.01 1-methyl 2-ethyl benzene 9 152 0.01 pseudocumene 9 168.5 0.02 indane 9 176.5 0.01 butyl benzene 10 183 0.01 1,3-diethyl benzene 10 182 0.01
Reactor and Catalyst Test Conditions

(4) Referring to Experiments 1 to 5, the hydrocracking of a hydrocarbon feed stream employing catalysts described in this application were performed using stainless steel tube reactor as described below. 0.5 grams (g) of catalyst (sized 20-40 mesh) was diluted to 4 milliliters (ml) by premixing with SiC (30 grit) and was loaded in a reactor.

(5) Reactor description: inch () inch tube, 0.035 wall thickness. thermocouple with a spacer bar; 121 aluminum over-sleeve; reactor bed is approximately 4 inches in length in the center of the sleeve.

(6) The catalyst was pre-activated (drying, Pt reduction) by subjecting it to 100 standard cubic centimeters (sccm) of H.sub.2 per minute at 130 C. under 50 pounds per square inch gauge (psig) for 2 hours and subsequently the temperature was raised to 350 C. (at 50 psig) for reduction under 200 sccm of H.sub.2 (with 50 parts per million by weight (ppm) of H.sub.2S) for 30 min.

(7) Hereinafter, standard feed refers to a feed consisting of 70 wt % benzene, 15 wt % methylcyclopentane and 15 wt % 3-methylpentane. In all Experiments 1 to 5, the standard feed was first introduced to the reactor containing specific catalyst at hydrocracking reaction conditions as described below and continued for a minimum of 15 hours to establish a steady cracking activity. Subsequently, the standard feed was replaced by the feed containing a specific branched hydrocarbon as described for each experiment. All components of the hydrocracking feed stream are Aldrich regent grade chemicals dried under 4 A molecular sieves overnight.

(8) The standard feed was introduced to the reactor at a temperature of 470 C. and a pressure of 200 psig. The molar ratio of H.sub.2 to the hydrocarbons was 4 to 1, and the H.sub.2S content was 50 ppm based on the total hydrocarbon and H.sub.2 feed. In all experiments, the same WHSV was maintained.

(9) Experiment 1

(10) Feeds were prepared by adding one of the compounds shown in Table 1 (hydrocarbons having boiling point of 75 to 90 C.) to a feed containing benzene, methylcyclopentane (MCP) and 3-methylpentane (3MP). The resulting feeds contained 70 wt % benzene, 15 wt % methylcyclopentane (MCP), 10 wt % 3-methylpentane (3MP), and 5 wt % of one of the compounds shown in Table 1. In each of examples (column 1 in Table 1), after initial stable activity with the standard feed, each of the feeds containing 5 wt % of one of the components (column 1 in Table 1) was subjected to hydrocracking at 470 C., about WHSV 10/h and 200 psig.

(11) The feed stream contains H.sub.2 (H.sub.2/HC molar 4) and 50 ppm S (fed H.sub.2S). The hydrocracking catalyst used was a powder catalyst of ZSM-5 deposited with Pt (no binder), wherein the amount of Pt was 0.03 wt % of the total catalyst and the silica to alumina molar ratio of the ZSM-5 was 50.

(12) The result of the conversion is shown in Table 1. It can be seen that the conversion of 2,4-dimethylpentane (24DMP) and 2,2,3-trimethylbutane (223TMB) is low, e.g., under 80% and under 30% conversion respectively. It can be understood that it is difficult to obtain a product stream with substantially no benzene co-boilers from a feed stream comprising large amounts of 24DMP and/or 223TMB, while other hydrocarbons can be substantially completely converted.

(13) TABLE-US-00002 TABLE 1 Nonaromatics Carbon # b.p., C. % Conversion 2,2-dimethylpentane 7 78 100.0 2,4-dimethylpentane 7 80 78.3 2,2,3-trimethylbutane 7 81 27.7 2,3-dimethylpentane 7 89 99.7 2-methylhexane 7 90 100 cyclohexane 6 81 99.4
Experiment 2: Effect of Extrudate vs Powder on 223TMB Cracking

(14) In each of the examples, after initial stable activity with the standard feed, a feed containing 70 wt % benzene, 15 wt % methylcyclopentane (MCP), 10 wt % 3-methylpentane (3MP) and 5 wt % of 2,2,3-trimethylbutane (223TMB) was subjected to hydrocracking at 470 C., about WHSV 10/h and 200 psig. The feed stream contains H.sub.2 (H.sub.2/HC molar 4) and 50 ppm S (fed H.sub.2S).

(15) In CEx 1-2, the catalysts used were a Pt deposited ZSM-5 powder catalyst with no binder. In Ex 3-5, the catalysts used were in the form of an extrudate of ZSM-5 and alumina on which Pt was deposited. The silica-to-alumina molar ratio of the ZSM-5 is 50. The amount of Pt in the catalyst is shown in Table 2.

(16) TABLE-US-00003 TABLE 2 223TMB conversion Catalyst Averaged Exam- Pt Conversion during Deactivation ple Pt on (wt %) (%) tos (h) rate.sup.1 (hr.sup.1) CEx1 ZSM-5 0.032 27.7 30-79 not estimated powder CEx2 ZSM-5 0.102 36.5 56-71 not estimated powder Ex3 ZSM-5 0.067 52.7 30-48 |4.2 10.sup.3| extrudates Ex4 ZSM-5 0.15 74.6 50-60 |6.1 10.sup.3| extrudates Ex5 ZSM-5 0.25 83.7 52-70 |3.4 10.sup.3| extrudates .sup.1Deactivation rate: absolute value of the decrease of % conversion of 223TMB per hour calculated during time-on-stream (tos) is indicated.

(17) It can be understood that an increased amount of Pt shows an increase in the conversion of 223TMB for both the powder form and the extrudate form. However, the extrudate shows a higher conversion than the powder even at a low Pt content (comparison of CEx2 with 0.102 wt % Pt vs Ex3 with 0.067 wt % Pt). It can be concluded that the extrudate shows a better conversion than the powder at the same Pt content.

(18) Experiment 3: Effect of Large Pore Zeolite on 24DMP Cracking

(19) In each of the examples, after initial stable activity was achieved with the standard feed, a feed containing 70 wt % benzene, 15 wt % methylcyclopentane (MCP), 10 wt % 3-methylpentane (3MP), and 5 wt % of 24DMP was subjected to hydrocracking at 470 C., about WHSV 10/h and 200 psig. The feed stream contained H.sub.2 (H.sub.2/HC molar 4) and 50 ppm S (fed H.sub.2S).

(20) In CEx 6-7, the catalysts used were a Pt deposited ZSM-5 powder catalyst with no binder. In Ex 8-11, the catalysts used were in the form of a physical mixture of a Pt deposited ZSM-5 powder catalyst and a Pt deposited large pore zeolite powder catalyst. The silica-to-alumina molar ratio of the ZSM-5 is 50. The silica-to-alumina molar ratio of the large pore zeolites are shown in Table 3. The amounts of Pt in the catalyst are shown in Table 3.

(21) TABLE-US-00004 TABLE 3 24DMP Zeolite Catalyst conversion Pt, wt %, avgd in mixed % during Deactivation Example Description zeolite.sup.2 conv tos (h) rate.sup.1 (hr.sup.1) CEx 6 100 wt % of Pt(0.03%)/ZSM-5 0.03 78.3 31-82 |3.3 10.sup.4| CEx 7 100 wt % of Pt(0.097%)/ZSM-5 0.097 93.9 29-48 |4.9 10.sup.4| Ex 8 80 wt % of 20 wt % of 0.051 92.3 18-87 |2.0 10.sup.4| Pt(0.04%)/ Pt(0.094%)/ ZSM-5, SAR 50 HY, SAR 60 Ex 9 80 wt % of 20 wt % of 0.051 93.3 17-45 |0.96 10.sup.4| Pt(0.04%)/ Pt(0.096%)/ ZSM-5, SAR 50 HY, SAR 30 Ex 10 80 wt % of 20 wt % of 0.054 98.1 200-255 |1.7 10.sup.5| Pt(0.04%)/ Pt(0.11%)/ ZSM-5, SAR 50 Beta, SAR 20 Ex 11 80 wt % of 20 wt % of 0.052 99 17-39 no apparent Pt(0.04%)/ Pt(0.102%)/ deactivation ZM-5, SAR 50 Mordenite, SAR 20 SAR = silica (SiO.sub.2) to alumina (Al.sub.2O.sub.3) molar ratio .sup.1Deactivation rate: absolute value of the decrease of % conversion of 24DMP per hour calculated during time-on-stream (tos) indicated. .sup.2Estimated from Pt contents in ZSM-5 and the other large pore zeolite.

(22) The mixtures of a medium pore zeolite catalyst and a large pore zeolite catalyst show a high conversion rate of more than 92% at Pt content of 0.051 wt %. From CEx6 and CEx7, a catalyst without a large pore zeolite having a Pt content of 0.051 wt % can be estimated to have a conversion of 83.2% from the relationship between the Pt content and the conversion. It is further noted that the catalyst containing a mixture of a large pore zeolite catalyst and a medium pore zeolite catalyst had nearly half the amount of hydrogenating metal yet attained a conversion of 24DMP of greater than 90%. It can be concluded that a catalyst containing a mixture of a large pore zeolite catalyst and a medium pore zeolite catalyst shows an unexpectedly better conversion than a catalyst containing only medium pore zeolite catalyst, and the deactivation was slower. For deactivation rate, the absolute values of the rate are compared. The larger the absolute value of the deactivation rate, the faster the catalyst deactivates.

(23) Experiment 4: Effect of Silica-to-Alumina Ratio (SAR) on 24DMP Cracking

(24) In each of examples, after initial stable activity with the standard feed, a feed containing 70 wt % benzene, 15 wt % methylcyclopentane (MCP), 10 wt % 3-methylpentane (3MP), and 5 wt % of 24DMP was subjected to hydrocracking at 470 C., about WHSV 10/h and 200 psig. The feed stream contains H.sub.2 (H.sub.2/HC molar 4) and 50 ppm S (fed H.sub.2S). The hydrocracking catalysts comprised Pt deposited ZSM-5 powder catalyst with no binder. The amount of Pt and the silica-to-alumina ratio of the ZSM-5 are summarized in Table 4. The result of the conversion is shown in Table 4.

(25) TABLE-US-00005 TABLE 4 24DMP Conversion averaged during Deactivation Example SiO.sub.2/Al.sub.2O.sub.3 Pt (wt %) % conv tos (h) rate.sup.1 (hr.sup.1) REx12 80 0.094 62.9 32-100 |7.6 10.sup.4| REx13 50 0.097 94.0 29-48 |4.9 10.sup.4| REx14 30 0.099 98.6 27-43 not observed REx15 23 0.101 99.6 28-100 not observed .sup.1Deactivation rate: absolute value of the decrease of % conversion per hour calculated during time-on-stream (tos) indicated.

(26) The comparison of Reference Experiments 12-15 shows that a lower molar ratio of silica to alumina led to a higher conversion rate of 24DMP. In particular, the catalysts having a molar ratio of silica to alumina of 23-30 showed an extremely high conversion and no decline in 24DMP conversion with no apparent catalyst deactivation during the time on stream indicated.

(27) Experiment 5: Effect of Pt Loading on 24DMP Cracking

(28) In each of examples, after initial stable activity with the standard feed, a feed containing 70 wt % benzene, 15 wt % methylcyclopentane (MCP), 10 wt % 3-methylpentane (3MP), and 5 wt % of 24DMP was subjected to hydrocracking at 470 C., about WHSV 10/h and 200 psig. The feed stream contains H.sub.2 (H.sub.2/HC molar 4) and 50 ppm S (fed H.sub.2S). The hydrocracking catalysts used were extrudates of ZSM-5 and a binder, wherein Pt was deposited on the extrudates. The silica-to-alumina molar ratio of the ZSM-5 was 50. The amount of Pt is summarized in Table 5. The result of the conversion is shown in Table 5.

(29) TABLE-US-00006 TABLE 5 24DMP Conversion averaged Catalyst conversion during Deactivation Example Pt (wt %) (%) tos (hr) rate.sup.1 (hr.sup.1) Ex 16 0.067 90.4 126-169 |5.1 10.sup.4| Ex 17 0.079 93.5 47-71 |6.0 10.sup.4| Ex 18 0.15 99.5 50-62 |3.5 10.sup.4| Ex 19 0.25 99.8 59-70 |1.7 10.sup.4| .sup.1Deactivation rate: decrease of % conversion per hour calculated during time-on-stream (tos) indicated.

(30) A higher Pt amount led to a higher conversion of 24DMP. A higher Pt amount also led to less catalyst deactivation.

(31) Desirably, the hydrocracking catalyst, when cracking 2,4-dimethylpentane and/or 2,2,3-trimethylbutane, has a deactivation rate (i.e., decline in conversion percent) of less than the absolute value of 3.510.sup.4 hr.sup.1 (e.g., |3.510.sup.4 hr.sup.1|), for example, less than or equal to |3.010.sup.4 hr.sup.1|, or less than or equal to |2.510.sup.4 hr.sup.1|, or less than or equal to |2.010.sup.4 hr.sup.1|, most preferably less than or equal to |1.010.sup.4 hr.sup.1|.

(32) Set forth below are some embodiments of the methods disclosed herein.

Embodiment 1

(33) A method of hydrocracking at least one of 2,4-dimethylpentane and 2,2,3-trimethylbutane, comprising: contacting a hydrocracking feed stream in the presence of hydrogen with a hydrocracking catalyst under process conditions including a temperature of 425-580 C., a pressure of 300-5000 kPa gauge and a Weight Hourly Space Velocity of 0.1-30 h.sup.1 to produce a hydrocracking product stream comprising benzene (e.g., comprising BTX and LPG); wherein the hydrocracking feed stream comprising C.sub.5-C.sub.12 hydrocarbons which includes at least 0.5 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane, based upon a total weight of the hydrocracking feed stream; and wherein the hydrocracking catalyst comprises a hydrogenation metal in an amount of 0.010-0.30 wt % with respect to the total catalyst; and wherein the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75; preferably the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75 and a large pore zeolite having a pore size of 6-8 and a silica to alumina molar ratio of 10-80, wherein the hydrogenation metal is deposited on the medium pore zeolite and the large pore zeolite.

Embodiment 2

(34) The process according to Embodiment 1, wherein the total amount of 2,4-dimethylpentane and 2,2,3-trimethylbutane in the hydrocracking feed stream is at least 1.0 wt %, at least 2.0 wt %, or at least 5.0 wt %, with respect to total hydrocarbon feed.

Embodiment 3

(35) The process according to any one of Embodiments 1-2, wherein the hydrocracking catalyst comprises 0.08 to 0.25 wt % hydrogenation metal, 15 wt % to 25 wt % alumina, and a balance being the medium pore zeolite.

Embodiment 4

(36) The process according to any one of Embodiments 1-2, wherein the hydrocracking catalyst is in the form of powder and is free from a binder.

Embodiment 5

(37) The process according to any one of the preceding embodiments, wherein the silica to alumina molar ratio of the medium pore zeolite is in the range of 20-50, preferably 20 to 30, more preferably 21 to 29.

Embodiment 6

(38) The process according to any one of the preceding embodiments, wherein a conversion of any 2,4-dimethylpentane is greater than or equal to 90%, preferably greater than or equal to 95%, or greater than or equal to 98%; and the conversion of any 2,2,3-trimethylbutane is greater than or equal to 90%, preferably greater than or equal to 95%, or greater than or equal to 98%.

Embodiment 7

(39) The process according to any one of the preceding embodiments, wherein the hydrogenating metal is at least one element selected from Group 10 of the periodic table of elements, rhodium, and iridium; preferably at least one metal selected from palladium and platinum; most preferably platinum.

Embodiment 8

(40) The process according to any one of the preceding embodiments, wherein the hydrocracking catalyst comprises at least 0.030 wt %, at least 0.050 wt %, at least 0.075 wt %, at least 0.10 wt %, at least 0.125 wt % or at least 0.20 wt %, of the hydrogenating metal in relation to the total weight of the catalyst.

Embodiment 9

(41) The process according to any one of the preceding embodiments, wherein the hydrocracking catalyst comprises La and/or Ga, preferably at an amount of 0.10-0.40 wt % of the total weight of the catalyst.

Embodiment 10

(42) The process according to any one of the preceding embodiments, wherein the zeolite in the hydrocracking catalyst comprises 70-100 wt % of the medium pore zeolite and 0-30 wt % of the large pore zeolite with respect to the total amount of the zeolite.

Embodiment 11

(43) The process according to any one of the preceding embodiments, wherein the zeolite in the hydrocracking catalyst comprises 75-95 wt % of the medium pore zeolite and 5-25 wt % of the large pore zeolite with respect to the total amount of the zeolite.

Embodiment 12

(44) The process according to any one of the preceding embodiments, wherein the process comprises separating benzene from the hydrocracking product stream.

Embodiment 13

(45) The process according to any one of the preceding embodiments, wherein the hydrocracking catalyst has a deactivation rate of less than |3.510.sup.4 per hour|, preferably less than or equal to |3.010.sup.4 per hour|, or less than or equal to |2.510.sup.4 per hour|, most preferably less than or equal to |2.010.sup.4 per hour|.

Embodiment 14

(46) The process according to any one of the preceding embodiments, wherein the medium pore zeolite comprises a ZSM-5.

Embodiment 15

(47) The process according to any one of the preceding embodiments, wherein the large pore zeolite comprises a mordenite.

Embodiment 16

(48) The process according to any one of the preceding embodiments, wherein the hydrocracking catalyst has a deactivation rate of less than or equal to |2.510.sup.4 hr.sup.1|, or less than or equal to |2.010.sup.4 hr.sup.1|, or equal to |1.010.sup.4 hr.sup.1|.

Embodiment 17

(49) The process according to any one of the preceding embodiments, wherein a conversion percent of the 2,4-dimethylpentane and 2,2,3-trimethylbutane is greater than or equal to 95%, preferably greater than or equal to 98%, or greater than or equal to 99%, or greater than or equal to 99.5%.

Embodiment 18

(50) The process according to any one of the preceding embodiments, wherein greater than or equal to 95%, preferably greater than or equal to 98%, more preferably, greater than or equal to 99.8%, the C.sub.5-C.sub.12 hydrocarbons are cracked.

Embodiment 19

(51) The use of a hydrocracking catalyst to crack at least one of 2,4-dimethylpentane and 2,2,3-trimethylbutane, wherein the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75; preferably the hydrocracking catalyst comprises a medium pore zeolite having a pore size of 5-6 and a silica to alumina molar ratio of 20-75 and a large pore zeolite having a pore size of 6-8 and a silica to alumina molar ratio of 10-80, wherein the hydrogenation metal is deposited on the medium pore zeolite and the large pore zeolite.

Embodiment 20

(52) The use according to Embodiment 19, wherein the hydrocracking catalyst comprises 0.08 to 0.25 wt % hydrogenation metal, 15 wt % to 25 wt % alumina, and a balance being the medium pore zeolite.

Embodiment 21

(53) The use according to Embodiment 19, wherein the hydrocracking catalyst is in the form of powder and is free from a binder.

Embodiment 22

(54) The use according to any one of Embodiments 19-21, wherein the hydrogenating metal is at least one element selected from Group 10 of the periodic table of elements, rhodium, and iridium; preferably at least one metal selected from palladium and platinum; most preferably platinum.

Embodiment 23

(55) The use according to any one of Embodiment 19-22, wherein the hydrocracking catalyst comprises at least 0.030 wt %, at least 0.050 wt %, at least 0.075 wt %, at least 0.10 wt %, at least 0.125 wt % or at least 0.20 wt %, of the hydrogenating metal in relation to the total weight of the catalyst.

Embodiment 24

(56) The use according to any one of Embodiments 19-23, wherein the hydrocracking catalyst comprises La and/or Ga, preferably at an amount of 0.10-0.40 wt % of the total weight of the catalyst.

Embodiment 25

(57) The use according to any one of Embodiments 19-24, wherein the zeolite in the hydrocracking catalyst comprises 70-100 wt % of the medium pore zeolite and 0-30 wt % of the large pore zeolite with respect to the total amount of the zeolite.

Embodiment 26

(58) The use according to any one of Embodiments 19-25, wherein the zeolite in the hydrocracking catalyst comprises 75-95 wt % of the medium pore zeolite and 5-25 wt % of the large pore zeolite with respect to the total amount of the zeolite.

Embodiment 27

(59) The use according to any one of Embodiments 19-26, wherein the hydrocracking catalyst has a deactivation rate of less than |3.510.sup.4 per hour|, preferably less than or equal to |3.010.sup.4 per hour|, or less than or equal to |2.510.sup.4 per hour|, most preferably less than or equal to |2.010.sup.4 per hour|.

Embodiment 28

(60) The use according to any one of Embodiments 19-27, wherein the medium pore zeolite comprises a ZSM-5.

Embodiment 29

(61) The use according to any one of Embodiments 19-28, wherein the large pore zeolite comprises a mordenite.

Embodiment 30

(62) The use according to any one of Embodiments 19-29, wherein the silica to alumina molar ratio of the medium pore zeolite is in the range of 20-50, preferably 20 to 30, more preferably 21 to 29.

Embodiment 31

(63) The hydrocracking catalyst accordingly to any one of Embodiments 1-30, wherein the hydrocracking catalyst can be free of metals other than the Group 10 metals of the Periodic Table of Elements, rhodium, and iridium; preferably free of metals other than palladium and platinum.

Embodiment 32

(64) The use according to any of Embodiments 19-30 and the process according to any of Embodiments 1-18, further comprising separating the benzene from LPG, toluene and xylene, to produce a product stream, wherein the product stream has a benzene purity of greater than or equal to 99.80 wt %, preferably greater than or equal to 99.90 wt %, or greater than or equal to 99.95 wt %. It was unexpected that such a benzene purity could be obtained starting from a feed stream comprising at least 0.5 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane (e.g., 0.5 wt % to 15 wt % of 2,4-dimethylpentane and/or 2,2,3-trimethylbutane), based on a total weight percent of the hydrocracking feed stream.

(65) It is noted that the invention relates to all possible combinations of features described herein, preferred in particular are those combinations of features that are present in the claims. It will therefore be appreciated that all combinations of features relating to the composition according to the invention; all combinations of features relating to the process according to the invention and all combinations of features relating to the composition according to the invention and features relating to the process according to the invention are described herein.

(66) It is further noted that the term comprising does not exclude the presence of other elements. However, it is also to be understood that a description on a product/composition comprising certain components also discloses a product/composition consisting of these components. The product/composition consisting of these components may be advantageous in that it offers a simpler, more economical process for the preparation of the product/composition. Similarly, it is also to be understood that a description on a process comprising certain steps also discloses a process consisting of these steps. The process consisting of these steps may be advantageous in that it offers a simpler, more economical process.

(67) As used herein, deactivation rate is the slope of conversion versus the time-on-stream (tos). If the conversion is decreasing with time on stream, the slope is negative. The absolute value of the number is relevant. The larger the absolute value the faster the catalyst is deactivating. In other words, a catalyst having a deactivation rate of |5.010.sup.4 hr.sup.1| will deactivate 5 times faster than a catalyst having a deactivation rate of |1.010.sup.4 hr.sup.1|. Unless specified otherwise, the deactivation rate is per hour (hr.sup.1).

(68) When values are mentioned for a lower limit and an upper limit for a parameter, ranges made by the combinations of the values of the lower limit and the values of the upper limit are also understood to be disclosed.