WO2016048879A1

WO2016048879A1 - Forming normal alkanes

Info

Publication number: WO2016048879A1
Application number: PCT/US2015/051189
Authority: WO
Inventors: Thomas DAVIDIAN; Andrzej Malek
Original assignee: Dow Global Technologies Llc
Priority date: 2014-09-23
Filing date: 2015-09-21
Publication date: 2016-03-31

Abstract

Form normal alkanes via a process that includes contacting synthesis gas with a modified cobalt catalyst. The modified cobalt catalyst can include mordenite, cobalt, an alkali metal, sulfur, and an optional reduction promoter.

Description

FORMING NORMAL ALKANES

[001] This disclosure relates to processes for forming normal alkanes, and in particular forming normal alkanes having five to twenty carbon atoms.

[002] Previous processes have utilized zeolites to produce liquid hydrocarbon products for steam cracking applications. However, the liquid hydrocarbon products of the previous processes have large fractions of olefins and/or branched hydrocarbons.

[003] Normal alkanes having five to twenty carbon atoms (C5-C20 n-alkanes), and/or subsets thereof, can be used as feedstock for steam cracking applications to produce ethylene and/or propylene, for example. C5-C20 n-alkanes are desirable for these steam cracking applications because the C₅-C₂o n-alkanes can provide improved yields of product, such as ethylene and/or propylene, and/or help reduce coking of stream cracking units, as compared to other hydrocarbons, such as branched alkanes and olefins. For instance, steam cracking applications utilizing a feed of C5-C20 n-alkanes can provide an ethylene/ propylene yield of 60% or greater, while steam cracking applications utilizing a feed of reduced n-alkanes, e.g., approximately 50% C5-C20 n-alkanes with a remaining portion of other alkanes and/or olefins, can provide an ethylene/ propylene yield of about 45%.

[004] This disclosure provides a process for forming C5-C20 n-alkanes, and/or subsets thereof, including contacting synthesis gas with a modified cobalt catalyst. For instance, a feed stream including synthesis gas can contact the modified cobalt catalyst. Advantageously, the process provides desirable C5-C20 n-alkane selectivity. Additionally advantageously, the process provides for direct formation, e.g., without an intermediate hydrocarbon processing step such as hydrocracking of C₂i+ hydrocarbons, of C₅-C₂o n- alkanes, which may be utilized for steam cracking applications, for instance.

Surprisingly and in contrast to other catalysts, it has been found that utilizing the modified cobalt catalyst, which includes mordenite, an alkali metal, and sulfur as discussed further herein, can provide a product stream of liquid hydrocarbons having a C₅ to C20 n-alkane content of at least 70 wt% based upon a total weight of the liquid product stream, and that the C5-C20 n-alkane content was greatly enhanced compared to when these elements were not combined.

[005] Synthesis gas, which may be referred to as syn gas, includes carbon monoxide (CO) and hydrogen (¾). The syn gas can be from 15 mole percent CO to 50 mole percent CO and 50 mole percent H₂ to 85 mole percent H₂. Some embodiments of the present disclosure provide a diluent gas, such as helium, nitrogen, or carbon dioxide, among others, may be utilized with the syn gas, e.g, as a component of the feed stream. Various amounts of the diluent gas can be utilized for differing applications.

[006] The modified cobalt catalyst includes mordenite, e.g. a mordenite support, cobalt, an alkali metal, sulfur, and an optional reduction promoter. The modified cobalt catalyst includes a mordenite support. The mordenite support includes a mordenite zeolite and optionally a binder material, such as silica, alumina, clay, or combinations thereof, among others. Mordenite is a natural or synthetic zeolite; mordenite is a microporous crystalline aluminum silicate with a structure that can be represented by the MOR structure type according to IZA (International Zeolite Association). Mordenite can be represented by the following chemical formula: (M₂)Al₂Siio0₂₄-7H₂0, where M is a univalent cation, such as a proton or an alkali metal cation. For some applications, the ratio of Al to Si can be 2: 10; however this ratio can vary for differing applications. The mordenite support can be obtained from commercial suppliers or synthesized according to methods known to those skilled in the art. An example of mordenite synthesis method can be found in the handbook titled "Verified synthesis of zeolitic materials", p212, Second revised edition, 2001, Elsevier.

[007] The modified cobalt catalyst includes cobalt. The cobalt can be present in an amount within a range of from 1 to 25 weight percent (wt%) based upon a dry weight of the modified cobalt catalyst. Throughout this disclosure, all individual values and subranges from a lower limit associated with a range to an upper limit associated with the range are included herein and disclosed herein; for instance, as mentioned cobalt can be present in an amount within a range of from 1 to 25 weight percent, therefore cobalt can be present in an amount within a range of from 2 to 25 weight percent, 3 to 25 weight percent, 5 to 25 weight percent, 1 to 23 weight percent, 1 to 20 weight percent, or 1 to 15 weight percent, for example. The dry weight of the modified cobalt catalyst is determined as combined weight of components of the modified cobalt catalyst after calcination, excluding any adsorbed water. Some embodiments of the present disclosure provide that the dry weight of the modified cobalt catalyst is a combined weight of the mordenite, the alkali metal, and the sulfur. Some embodiments of the present disclosure provide the cobalt is present in an amount within a range of from 5 to 20 wt% based upon a dry weight of the modified cobalt catalyst.

[008] The modified cobalt catalyst includes an alkali metal. An example of the alkali metal is sodium, among others. The alkali metal can be present in an amount within a range of from 0.01 to 4.50 wt% based upon a dry weight of the modified cobalt catalyst. Some embodiments of the present disclosure provide the alkali metal can be present in an amount within a range of from 0.1 to 3.5 wt% or from 0.1 to 4.5 wt% based upon the dry weight of the modified cobalt catalyst.

[009] The modified cobalt catalyst includes sulfur. For instance, the sulfur can be incorporated into the modified cobalt catalyst via sulfate (S0₄), among others. The sulfur can be present in an amount within a range of from 0.01 to 1.00 wt% based upon a dry weight of the modified cobalt catalyst. Some embodiments of the present disclosure provide the sulfur can be present in an amount within a range of from 0.01 to 0.05 wt% or from 0.05 to 0.50 wt% based upon the dry weight of the modified cobalt catalyst.

[010] The modified cobalt catalyst can include optional reduction promoter.

Examples of the optional reduction promoter are ruthenium, platinum, and palladium, among others. When utilized, the optional reduction promoter can be present in an amount within a range of from 0.01 to 5.00 wt% based upon a dry weight of the modified cobalt catalyst. Some embodiments of the present disclosure provide that the optional reduction promoter can be present in an amount within a range of from 0.05 to 2.50 wt% based upon the dry weight of the modified cobalt catalyst.

[011] The modified cobalt catalyst can be prepared by various processes. As mentioned, the mordenite support can be obtained from commercial suppliers or synthesized. The mordenite support can include sodium and/or sulfate via selection of precursors containing sodium and/or sulfate for mordenite support synthesis. Sodium and/or sulfate concentrations of the mordenite support can be adjusted by techniques known to those skilled in the art. For instance, an ion exchange of sodium with a solution containing ammonium nitrate can decrease the sodium concentration. Additionally, sulfate concentration can be reduced by washing, e.g., repeated washings, with deionized water. Further, techniques for increasing the sodium concentration and/or sulfate concentration include, but are not limited to, incipient wetness impregnation of sodium and or sulfate containing precursors, wet impregnation, mechanical mixing, and chemical vapor deposition. The sodium and sulfate precursors may be added sequentially or simultaneously. Intermediate drying and/or calcination steps may be utilized.

[012] The modified cobalt catalyst can be prepared by techniques known to those skilled in the art. Examples of such techniques involve impregnation, e.g., utilizing an aqueous or an organic solution containing one or more cobalt precursors followed by drying and calcination. Repeated impregnation steps may be utilized to obtain a cobalt concentration as discussed herein. Repeated impregnation steps may be separated by a drying step or a drying step followed by a calcination step, for instance. Examples of cobalt precursors include cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt

acetylacetonate, and mixtures thereof, among others. Some embodiments of the present disclosure provide that optional reduction promoter precursors can be dissolved in a solvent, e.g., water, methanol , ethanol, acetone, or dissolved in the solution containing the cobalt precursor and then impregnated onto the mordenite support, followed by drying and calcination steps. Optional reduction promoter precursors may include salts with counter anions of nitrate, acetate, chloride, nitrosyl, or mixtures thereof, among others.

[013] The modified cobalt catalyst can be calcined, e.g., to decompose precursors, such as cobalt precursors and/or optionally reduction promoter precursors, that have been deposited onto the support. Calcining can be performed in air, an inert gas, or a mixture thereof. For instance, a flow of air may be used. Conditions for calcining include a temperature within a range of 200 °C to 400 °C, and a calcination time interval within a range of 1 hour to 24 hours.

[014] The modified cobalt catalyst can be activated. Embodiments of the present disclosure provide that conditions for activating the modified cobalt catalyst include contacting the modified cobalt catalyst with a reducing agent. An example of the reducing agent is hydrogen, among others. Embodiments of the present disclosure provide that conditions for contacting the modified cobalt catalyst with the reducing agent include a gas hourly space velocity (GHSV) within a range of 5 to 100000 h^"1. Some embodiments of the present disclosure provide that the GHSV is within a range of 100 to 5000 h^"1 or 25 to 2500 h^"1. GHSV is a quotient of a volumetric flow

rate of reactants, e.g., the reducing agent, and a catalyst bed volume, e.g., the modified cobalt catalyst.

[015] Conditions for activating the modified cobalt catalyst include a temperature, e.g., a reducing temperature, within a range of from 125 to 325 °C. Some embodiments of the present disclosure provide that the reducing temperature is within a range of from 150 to 300 °C. When sulfate is utilized, a reducing temperature of 350 °C or greater can be detrimental to the catalyst activity.

[016] The modified cobalt catalyst can be activated, e.g., contacted with the reducing agent at the reducing temperature, for a time interval within a range of 0.1 to 48 hours. Some embodiments of the present disclosure provide that the time interval within a range of 1 to 15 hours.

[017] As mentioned, this disclosure provides a process for forming C5-C₂₀ n- alkanes includes contacting a synthesis gas feed stream with a modified cobalt catalyst. Embodiments of the present disclosure provide that conditions for contacting the synthesis gas feed stream with the modified cobalt catalyst include a GHSV within a range of 100 to 100000 h^"1. Some embodiments of the present disclosure provide that the GHSV is within a range of 500 to 5000 h^"1 or 300 to 2500 h^"1.

[018] Conditions for contacting the synthesis gas feed stream with the modified cobalt catalyst include a temperature, e.g., a reaction temperature, within a range of from 150 to 300 °C. Some embodiments of the present disclosure provide that the reaction temperature is within a range of from 200 to 275 °C.

[019] Conditions for contacting the synthesis gas feed stream with the modified cobalt catalyst include a pressure, e.g., a reaction pressure, within a range of from 2 to 100 bar. Some embodiments of the present disclosure provide that the reaction pressure is within a range of from 5 to 40 bar. [020] Embodiments of the present disclosure provide that a liquid product stream, e.g., a hydrocarbon product stream, has a C5-C20 n-alkane content of at least 70 wt% based upon a total weight of the liquid product stream. For example, the product stream of the present disclosure can have a C5-C20 n-alkane content in a range having a lower value of 70 wt% , 75 wt%, or 79 wt% to an upper value of 99 wt%, 98 wt%, or 97 wt%. Some embodiments of the present disclosure provide that the liquid product stream has a C5-C20 n-alkane content of at least 80 wt% and some other embodiments of the present disclosure provide that the liquid product stream has a C5-C20 n-alkane content of at least 90 wt%.

[021] Embodiments of the present disclosure provide that a liquid product stream, e.g., a hydrocarbon product stream, has a C7-C18 n-alkane content of at least 70 wt% based upon a total weight of the liquid product stream. For example, the product stream of the present disclosure can have a C7-C18 n-alkane content in a range having a lower value of 70 wt% , 75 wt%, or 79 wt% to an upper value of 99 wt%, 98 wt%, or 97 wt%. Some embodiments of the present disclosure provide that the liquid product stream has a C7-C18 n-alkane content of at least 80 wt% and some other embodiments of the present disclosure provide that the liquid product stream has a C7-C18 n-alkane content of at least 90 wt%.

EXAMPLES

[022] Materials include: mordenite (FM-8/25H, available from

ZEOCHEM®); mordenite (FM-8, available from ZEOCHEM®); mordenite (HSZ-690 HO A, available from Tosoh Corporation); ZSM-5 (CBV8014, zeolite, available from Zeolyst International); cobalt nitrate hexahydrate (cobalt precursor, ACS reagent > 98%, available from Sigma Aldrich); ruthenium nitrosyl nitrate solution diluted in nitric acid (optional reduction promoter precursor, available from Sigma Aldrich); sodium sulfate (ACS reagent > 99%, anhydrous, available from Sigma Aldrich); ammonium sulfate (available from Sigma Aldrich); and sodium nitrate (available from Sigma Aldrich) [023] Form mordenite catalyst-1 as indicated. Press FM-8/25H into a one-inch diameter die to form a pellet, crush the pellet to form a powder, and sieve the powder. Collect a 20-40 mesh fraction to obtain a mordenite support. Calcine the mordenite support in air at 500 °C for four hours to obtain a calcined mordenite support (4 grams (g)). Prepare a cobalt precursor solution (20 milliliter (mL)) having a cobalt

concentration of 2 moles/liter (mol/L) by dissolving cobalt nitrate hexahydrate (11.6 g) in deionized water; prepare the precursor solution by mixing in a vial: cobalt precursor solution (4.7 mL), ruthenium nitrosyl nitrate solution (0.59 mL, 1.5 wt% Ru) and de- ionized water (2.2 mL). Impregnate precursor solution (2 mL) onto the calcined mordenite support; dry for two hours at 100 °C. Repeat the impregnation and drying steps two additional times; then calcine in air for two hours at 300 °C to obtain the mordenite catalyst- 1.

[024] Form mordenite catalyst-2 as mordenite catalyst- 1, with that change that ruthenium nitrosyl nitrate solution is not utilized and the de-ionized water amount added to the precursor solution is 2.8 mL.

[025] Form mordenite catalyst-3 as mordenite catalyst- 1, with that changes that

HSZ-690 HOA is utilized rather than FM-8/25H; prior to the impregnation with the precursor solution, impregnate sodium sulfate solution (0.0412 g of Na₂S0₄ dissolved in 1.4 mL de-ionized water) to provide 0.3 wt% sodium and 0.21 wt % sulfur, dry for two hours at 100 °C and calcine in air for four hours at 500 °C. Prepare the cobalt precursor solution by dissolving cobalt nitrate hexahydrate precursor (2.1949 g) and ruthenium nitrosyl nitrate solution (0.4445 g, 3 wt% Ru in the solution) into de-ionized water (4.5 ml) and impregnate the cobalt precursor solution (1.5 ml) onto the calcined mordenite support, dry and repeat impregnation and drying steps two times, calcine as described for mordenite catalyst- 1.

[026] Form ZSM-5 catalyst-A as mordenite catalyst- 1, with that changes that

ZSM-5 is utilized rather than FM-8/25H; prior to the impregnation with the precursor solution, impregnate sodium nitrate solution (0.044g dissolved in 1.4 mL of de-ionized water) to provide 0.3 wt% sodium; dry for two hours at 100 °C and calcine in air for four hours at 500 °C. Prepare the cobalt precursor solution by dissolving cobalt nitrate hexahydrate precursor (2.1949 g) and ruthenium nitrosyl nitrate solution (0.4445 g, 3 wt% Ru in the solution) into de-ionized water (4.5 ml) and impregnate of the cobalt precursor solution (1.5 ml) onto the calcined mordenite support, dry and repeat impregnation and drying steps two times, calcine as described for mordenite catalyst- 1. [027] Form ZSM-5 catalyst-B as mordenite catalyst- 1, with that changes that

ZSM-5 is utilized rather than FM-8/25H; prior to the impregnation with the precursor solution, impregnate ammonium sulfate solution (0.0378 g dissolved in 1.4 mL of de- ionized water) to provide 0.2 wt% sulfur; dry for two hours at 100 °C and calcine in air for four hours at 500 °C.

[028] Form ZSM-5 catalyst-C as mordenite catalyst- 1, with that changes that

ZSM-5 is utilized rather than FM-8/25H; prior to the impregnation with the precursor solution, impregnate a solution containing sodium nitrate (0.0493 g) and ammonium sulfate (0.0378 g) dissolved in de -ionized water (1.4 mL) to provide 0.3 wt% sodium and 0.2 wt % sulfur, dry for two hours at 100 °C and calcine in air for four hours at 500 °C. Prepare the cobalt precursor solution by dissolving cobalt nitrate hexahydrate precursor (2.1949 g) and ruthenium nitrosyl nitrate solution (0.4445 g, 3 wt% Ru in the solution) into de -ionized water (4.5 ml) and impregnate the cobalt precursor solution (1.5 ml) onto the calcined mordenite support, dry and repeat impregnation and drying steps two times, calcine as described for mordenite catalyst- 1.

[029] Form ZSM-5 catalyst-D as mordenite catalyst- 1, with that changes ZSM-5 is utilized rather than FM-8/25H; prior to the impregnation with the precursor solution, impregnate sodium sulfate solution (0.0412 g dissolved in 1.4 mL of de-ionized water) to provide 0.3 wt% sodium and 0.2 wt % sulfur, dry for two hours at 100 °C and calcine in air for four hours at 500 °C. Prepare the cobalt precursor solution by dissolving cobalt nitrate hexahydrate precursor (2.1949 g) and ruthenium nitrosyl nitrate solution (0.4445 g, 3 wt% Ru in the solution) into de-ionized water (4.5 ml) and impregnate the cobalt precursor solution (1.5 ml) onto the calcined mordenite support, dry and repeat impregnation and drying steps two times, calcine as described for mordenite catalyst- 1.

[030] Form mordenite catalyst-E as mordendite catalyst- 1, with that changes

FM-8, having a sodium concentration of about 5 wt%, is utilized rather than FM-8/25H to provide mordenite catalyst-E.

[031] Form ZSM-5 catalyst-F as mordenite catalyst- 1, with that changes ZSM-5 is utilized rather than FM-8/25H. Prepare the cobalt precursor solution by dissolving cobalt nitrate hexahydrate precursor (2.1949 g) and ruthenium nitrosyl nitrate solution (0.4445 g, 3 wt% Ru in the solution) into de-ionized water (4.5 ml) and impregnate the cobalt precursor solution (1.5 ml) onto the calcined mordenite support, dry and repeat impregnation and drying steps two times, calcine as described for mordenite catalyst- 1.

[032] Determine composition of the catalysts by X-ray fluorescence analysis; weight percents are shown in Table 1.

Table 1

[033] Example (Ex) 1

[034] Mix mordenite catalyst- 1 (1 gram (g)) with silicon carbide (3 milliliters

(mL)); load the mixture into a tubular reactor. Purge the reactor system with nitrogen (50 milliliters per minute (mL/min)) and heat the reactor to 150 °C at a rate 5° C/min. Stop nitrogen flow and introduce hydrogen (50 mL/min) at 150 °C and one bar for one hour. Maintain hydrogen flow and increase temperature to by 1 °C /minute to 250 °C and maintain for 10 hours. Pressurize to 10 bar with hydrogen flow. Maintain temperature, stop hydrogen flow, add flow including carbon monoxide, hydrogen, and helium to provide a gas hourly space velocity of 1500 h^"1 and a composition of 60 mole percent hydrogen, 30 mole percent carbon monoxide, and 10 mole percent helium, stabilize the reactor system for a time on stream time of 76 hours and produce liquid product stream. Send reactor effluent to a knock out vessel heated to 170 °C, add nitrogen (100 mL/min) to flow exiting the knock out vessel. Analyze with an Agilent 7890A Gas

Chromatography system equipped with a 2D analysis system to analyze and quantify C₇- C30 hydrocarbons and a ID system to analyze C1-C10 hydrocarbons to determine carbon monoxide conversion and product distribution. Calculate distribution of products independently, i.e. without normalization. Product distribution shown in Table 4.

[035] Exs 2-6

[036] Repeat Ex 1, with any changes indicated in Table 2. Product distribution is shown in Table 4.

[037] Comparative Example (Com Ex) A

[038] Repeat Ex 1, with any changes indicated in Table 3. Product distribution is shown in Table 5.

[039] Com Exs B-H

[040] Repeat Com Ex A, with any changes indicated in Table 3. Product distribution is shown in Table 5.

Table 2

Table 3

catalyst-F

ZSM-5

Com Ex N 240 20 1500 183 catalyst-F

ZSM-5

Com Ex 0 250 10 1500 66 catalyst-F

[041] Calculate carbon monoxide (CO) conversion by the following formula:

CO conversion = (1 - ^Hco'^{in ~ Hco>}°^ut ) _x 100%

nCO,in

where ncOi_n and nco_out are moles of CO fed to the reactor and exiting the reactor respectively.

[042] Calculate C5-C20 n-alkane % by the following formula:

20

C₅ - C₂₀n - alkane % = -¾ x 100%

∑Sc,

i=5

where S_n_ci is the selectivity of normal alkanes having a carbon number i, whrere, i is between 5 and 20, and SQ is the selectivity of alkanes or olefins having a carbon number i, whrere, i is between 5 and 20.

[043] Calculate C7-C18 n-alkane % by the following formula:

18

C₇ - C_l&n - alkane % = x 100%

∑Sc, where S_n_ci is the selectivity of normal alkanes having a carbon number i, whrere, i is between 7 and 18, and SQ is the selectivity of alkanes or olefins having a carbon number i, whrere, i is between 7 and 18.

[044] Calculate product selectivities independently, meaning apply no normalization. This is represented by the following formula:

i x n_r-

S_a % = x l00%

nCO,in ^{~ n}CO,out where SQ is selectivity to a hydrocarbon with carbon number i, ηα is the amount of moles formed of this hydrocarbon, and nco,in and nco,out are the moles of CO fed to the reactor and exciting the reactor respectively.

Table 4

Table 5

Com

32.9 18.9 13.3 68.0 1.6 35.1 27.9 33.8 Ex A

Com

18.5 33.9 35.4 60.1 1.5 28.5 60.5 11.9 Ex B

Com

21.4 18.9 20.6 40.4 0.6 26.7 56.2 12.3 Ex C

Com

21.1 23.9 24.8 41.2 1.5 35.1 44.6 19.7 Ex D

Com

30.1 23.2 25.2 56.2 1.3 35.2 31.8 22.2 Ex E

Com

23.1 21.69 23.2 44.0 1.5 34.2 35.7 19.4 Ex F

Com

24.3 23.1 25.3 53.2 1.6 34.7 30.5 20.5 Ex G

Com

27.2 20.3 21.7 56.2 1.4 33.4 24.5 21.7 Ex H

Com

35.5 15.4 10.7 49.1 0.1 20.3 49.4 17.3 Ex I

Com

22.2 16.2 12.6 61.3 0.5 48.1 23.5 50.3 Ex J

Com

14.6 16.3 13.7 60.3 0.2 35.4 36.1 37.0 Ex K

Com

52.6 16.1 13.9 66.1 3.2 31.2 38.7 29.2 Ex L

Com

24.2 17.3 15.6 55.6 0.6 59.1 23.8 62.9 Ex M

Com

26.6 14.1 15.6 44.6 0.4 56.3 26.5 60.6 Ex N

Com

38.5 19.2 16.2 42.1 0.1 49.4 32.9 52.4 Ex O

[045] The data in Table 4 show that the processes disclosed herein form n- alkanes. The data in Table 4 and Table 5 show that each of Examples 1-6 has improved C5-C20 n-alkane selectively, as evidenced by relatively greater C₅-C₂o n-alkane %, as compared to each of Comparative Examples A-O. Further, the data in Table 4 and Table 5 show that each of Examples 1-6 has improved C7-C18 n-alkane selectively, as evidenced by relatively greater C7-C18 n-alkane % as compared to each of Comparative Examples A-O. Additionally, the data in Table 4 and Table 5 show that each of Examples 1-6 has reduced olefin production as compared to each of Comparative Examples A-O.

Claims

Claims What is claimed:

1. A process for producing a liquid product stream that has a five to twenty carbon normal alkane content of at least 70 wt% comprising:

contacting synthesis gas with a modified cobalt catalyst, the modified cobalt catalyst consisting essentially of cobalt, an optional reduction promoter deposited on an alkali metal, and sulfur doped mordenite support, the alkali metal being present in an amount within a range of from 0.1 to 4.5 wt%, the sulfur being present in an amount within a range of from 0.01 to 0.50 wt%, the wt% of alkali metal and sulfur based upon a dry weight of the modified cobalt catalyst, the conditions consisting essentially of a temperature within a range of from 150 to 300 °C, a pressure within a range of from 5 to 40 bar, and a gas hourly space velocity within a range of from 100 to 10000 h^"1.

2. The process of claim 1, wherein the product stream consists essentially of normal alkanes within a range of five carbon atoms to twenty carbon atoms.

3. The process of claim 2, wherein the product stream consists essentially of normal alkanes within a range of seven carbon atoms to eighteen carbon atoms.

4. The process of claim 1, wherein the alkali metal is sodium.

5. The process of claim 1, wherein sulfur is present as a sulfate.