Patent Publication Number: US-3878261-A

Title: Hydroisomerization of paraffin hydrocarbon with a supported catalyst of SbF{HD 5 {B and CF{HD 3{B SO{HD 3{B H

Description:
United States Patent Gardner Apr. 15, 1975 HYDROISOMERIZATI ON OF PARAFFIN HYDROCARBON WITH A SUPPORTED [56] References Cited CATALYST OF SBF AND CF S0 H UNITED STATES PATENTS [75] Inventor: Lloyd E. Gardner, Bartlesville, 3,766,286 10/1973 Olah 260/683.68  
 Okla.  
  Primary Examiner-Delbert E. Gantz [73] Asslgnee&#39; gg gs g g gia Company Assistant ExaminerG. J. Crasanakis [22] Filed: Aug. 24, 1973 57 ABSTRACT [21] Appl. No.: 391,477 A method of isomerizing paraffins containing four to 12 carbon atoms contained in a feedstream by passing the feedstream into contact with hydrogen and with a (g1. Catalyst consisting of Supported Sb];5 and CFBSOJL 58 Field of Search 260/683.68, 666 P, 676 9 Claims, No ing HYDROISOMERIZATION OF PARAFFIN HYDROCARBON WITH ASUPPORTED CATALYST F SbFs-AND CFaSOaH This invention relates to sup e&#39;r&#39;acid catalysts.  
  In one of its more spjecificiaspects, this invention relates to the employment.of-a;supported super acid catalyst such .as. S&#39;bF.-, ain .-combination with CF SO H to isomerize C toC paraffins.  
  The isomerization of paraffms employing acids is well known. The present invention employs the super acid SbF and CF SO H in its supported form. the supports being selectedfrom the group consisting of fluorided alumina, potassium fluoride on alumina, sodium fluoride, aluminum phosphate. aluminum fluoride, charcoal and the like. i  
  The supported super acid catalyst of the present invention can be employed in n-heptane isomerization to give a higher ratio of 2,2,3-trimethy1butane to methyl hexanes than can be obtained by the use of supported SbF /HF super acid catalysts. Paraffins suitable for the present invention include C, to C alkanes, C to C a1- kanes being preferred.  
  While isomerization with acid catalysts can be carried out with the catalyst in the liquid phase. isomerization can be more easily carried out with the catalyst in the supported state. The use of the supported state tends to enable the employment of shorter contact times. while retaining the acid within a smaller portion of the system. For example, employment of the acid in the supported phase eliminates the need for agitator systems. separation drums, acid recirculation systems and the like. Further. there are advantages in handling the catalyst in a supported state over handling it in a liquid state since less acid is employed. The supported catalyst can be formed within the system in which it is to be employed and there is less difficulty in combating corrosion within the system and disposing of the spent catalyst.  
  The catalyst of the present invention can be prepared by contacting any suitable support with liquid trifluoromethanesonic acid and with antimony pentafluoride. Either component can be added first or they can&#39; be added simultaneously. Preferably, the support is positionedin a bed and the liquid CF SO H is passed downward into contact with the support in a stream of helium to facilitate the distribution of the acid on the surface of the support. Antimony pentafluoride vapor in helium diluent is then passed through the ractor to form the supported SbF and CF SO H complex catalyst. The helium stream is continued to remove any excess acid from the system.  
  The present process can be carried out under the following conditions:  
 Approximate Ranges As is well known in the art. naphthenes are used as cracking suppressor in acid catalyzed paraffin isomerization procedures. Such suppressors can constitute 0.1 to mole percent of hydrocarbon feedstocks used in isomerization processes.  
  The process of thid invention is demonstrated by the following examples.  
 EXAMPLE l A 13.37 g sample of fluorided alumina. containing 39.8 weight percent fluorine, was placed in a nickel tube reactor and after treatment with trifluoromethanesulfonic acid in a helium stream, the contents of the reactor showed a gain of 2.68 g, indicating the absorption of 0.0178 mole of CF SO H. The reactor contents were then treated with a helium-diluted stream of antimony pentafluoride until the system showed a weight gain of 4.19 g corresponding to the absorption of 0.0193 mole SbF This catalyst composite contained 33.9 weight percent total of SbF and CF SO H based on the total weight of the supported composition.  
  &#39;Normal-heptane isomerization was carried out employing the above supported catalyst at 24C about one atmosphere. 16.2 H /n-C molar ratio, and a gaseous space velocity of 618 V/V/hr. The charge contained 17.0 mole percent methlcyclohexane based on total hydrocarbon in the feedstock.  
  The total reactor effluent collected over a reaction period of 230 minutes was analyzed on a glc capillary column and the results were as follows:  
 From the above, the weight ratio of 2.2.3- trimethylbutane to methylhexanes is 0.2.  
 EXAMPLE [1 A 14.06 g sample of fluorided alumina was placed in a nickel tube reactor and treated with trifluoromethanesulfonic acid in a helium purge untilthe contents of the reactor showed a weight gain of 3.64 g indicating Parameter Suitable Preferred Temperature. C 8() to 0 to 35 Pressure (Atm.) 0.1 to 70 l to 5 Gaseous Space Velocity 5 to 5000 200 to 1000 (Volumes of gaseous feed/ Volume of Catalyst/Hour) Molar Ratio of H l Hydrocarbon in feedstock 0.1 to 100 1 to 20 Weight 71 of the total-of the total weight of the supported composition, v 1 to 40 15 to 35 Molar&#39;Ratio of SbF /CF SO H I on the support the absorption of 0.0242 mole of CF SO H. The reactor contents were then treated with a helium-diluted stream of antimony pentafluoride until the system showed a weight gain of 2.29 g corresponding to the ab- From the above, the weight percent ratio of 2,2,3- trimethylbutane to methylhexanes is about 0.11.  
 EXAMPLE lV sorption of 0.0105 mole SbF This catalyst composite 5 A supported SbF and HF catalyst on fluorided aluthen contained 29.7 weight percent total of SbF and mina was prepared as described in Example 111. This CF SO H based on the total weight of the supported catalyst contained 11.0 weight percent total of SbF composition. and HF based on the total weight of the supported com- Normal-heptane isomerization run was carried out position. over the above supported catalyst at about 0C, about A normal heptane isomerization run was carried out 1 atmosphere. 16.0 H /n-C molar ratio. and a gaseous over the above supported catalyst at about 0C, 1.0 atspace velocity of 600 V/V/hr. The charge contained mosphere, 15.8 H In-C molar ratio, and a gaseous 18.9 mole percent of methylcyclohexane based on total space velocity of 606 V/V/hr. The charge contained 18 hydrocarbon in the feedstock. mole percent methylcyclohexane based on total hydro- The total reactor effluent collected over a reaction carbon-in the feedstock. period of 195 minutes was analyzed on a glc capillary The total reactor effluent collected over a reaction column and the results were as follows: period of 345 minutes was analyzed on a glc capillary TABLE I] column and the results were as follows:  
  20 Reactor Effluent components Weight /1 TABLE IV h\ tl c l cjiz c 32 1 Reactor Effluent li-dimcthylpentanc 0.23 Compon n weight Z 4-dimenthypentanc 3.33  
  3 trimcthylbutant. 0.80 l 2- -dimcthylpcntane 0.30 (C;i+C +C -,+C.;) 0.28 2-niethvlhexunc 317 2.2-dimethylpentanc 1.41 ZJ-dinicthvl entune 1.20 l -d m y p man 12.9! S-mcthvlhxanc 1.44 2.2 .B-trimethylbutanc L80 0 77 3.3-dimethylpentane 2.28 Z-methylhexane 14.76 2.3-dimethylpentane 4.20 l 3-methylhexane 8.68 From the above, the ratio of 2.2,3-trimethylbutane to gl&#39; methylhexanes is 0.17.  
 EXAMPLE Ill A 12.20 g sample of fluorided alumina was placed in a nickel P P f&#34; and purged y nitrogen From the above, the ratio of 2,2,3-trimethylbutane to l-&#34;reshly distilled antimony pentafluoride was vaporized methylhexanes is about 0.08. into the reactor in a stream of helium at a temperature o the b i f th foregoing examples it can be seen of 25 C A Stream of HF vapor m helium dlluem was 40 that the weight percent ratio of 2,2,3-trimetliylbutane Passed through f reactor to form h sbF5 and to methylhexanes is less in the SbF and HF system (Ex- HF Supported Super acld catalyst- Approxlmmely L27 amples I11 and 1V) than in the inventive SbF and 8 total of the P and HF f absorbed to Produce CF3SO H system (Examples I and II). The difference in a catalyst containing 9.5 weight percent total of SbF selectivity is summarized in Table v and HF based on the total weight of the supported composition.  
  Isomerization of normal heptane over the above SbF and HF catalyst on fluorided alumina at 23C, 1.0 at- TABLE V mosphere, 17.3 H /n-C molar ratio, and a gaseous space velocity of 606 V/V/hr gave the results shown in C I f atalyst Reaction trlmethylbutane/ Table Ill. The charge contained 18 mole percent meth- Example System Temp. C. methylhexanes ylcyclohexane based on total hydrocarbon in the feed- I C as 7 stock. The results shown in Table 111 are based on capil- H b 8]., lary glc analysis of the total reactor effluent collected lll SbF /HF 24 on during a reaction period of 425 minutes. W SbFA/HF 0 (108 TABLE 111 Reactor Effluent C omponcnts Weight /1 EXAMPLE v n-heptane 65.36 (C +Q+C -,+C.;) 0.43 A 14.66 g sample of fluorided alumina was placed in z&#39;z&#39;dFnethylpemune a nickel tube reactor. The fluorided alumina was 2.4-dimethylpentane 9.34 2 2 3-trimethy]hu[ane 5 treated with a helium-diluted stream of antimony pengfiig s a y 83? tafluoride and the alumina showed a weight gain of igjg ffifii 1.32 g corresponding to the absorption of 0.0061 mole S-methylhexane 6.68 SbF The reactor contents were then treated with f 8f: trifluoromethanesulfonic acid with helium purge and the system showed a weight gain of 0.98 g, corresponding to the absorption of 0.0065 mole CF SO l-1. The catalyst composite contained 15.7 weight percent total of SbF and CF SO l-1 based on the total weight of the supported composition.  
  A normal hexane isomerization run was carried out over the supported catalyst produced above at about 25 C., 1.0 atmosphere, 4.9 H to n-C hydrocarbon molar ratio and a gaseous space velocity of 640 V/V/hr. The charge contained 5 mole percent methylcyclopentane based on total hydrocarbon in the feedstock and the average hydrogen flow rate was 107 cc/min.  
  Chromatographic analyses of the reactor effluent at various times on stream were as follows:  
 &#39; EXAMPLE Vll A catalyst was prepared as in Example V, and contained 1.20 g (0.0056 mole) SbF and 0.96 g (0.0064 mole) CF SO 1-l (molar ratio SbF CF SO l-l was represent, respectively. 2.2-dimethylhutane; diisopropyk 2.3-dimethylhutune); &#39;l-methylpentane; 3-methylpentane and n-hexane. No products boiling lower than 2.2-dimethylhutane were found.  
  The above data demonstrate isomerization of nhexane to more highly branched C isomers under the conditions employed EXAMPLE V1 The catalyst employed in Example V was purged with hydrogen and the isomerization of normal hexane was repeated with an average hydrogen flow rate of 101 cc/minute. The hydrogen to hydrocarbon molar ratio was about 16.8 and the gaseous space velocity was 535 V/V/hr. The other conditions were substantially as employed in Example V. A summary of the gas chromatographic analysis is presented in Table V11.  
 0.88). The catalyst composite contained 12.9 weight percent total of SbF and CF SO H based on the total weight of the supported composition.  
  A normal hexane isomerization run was carried out employing this catalyst at about C. 1 atmosphere 5 pressure, 18.0 H to n-C hydrocarbon molar ratio and a gaseous space velocity of 1050 volumes of gaseous feed per volume of catalyst per hour, at an average hydrogen flow rate of 199 cc/minute.  
  Analyses of the reactor effluent at various times during the course of the run were as follows:  
 TABLE V11 Reactor Efluent. wt.71&#34; Sample Time on Conversion 2,2- DlP &amp;  
 No. Stream. min. n-C DMB 2-MeC 3-MeC n-C &#34;Componcnts defined in Table VI footnotc&#34;.  
 TABLE V111 Reactor Effluent, Wtf/H&#39;&#34; Sample Time on &#34;/1- Conversion 2.2- 3- 2- No. Stream, hrs. n C DMB DIP MeC MeC n-C &#34;&#34;Components defined in Table V1 footnote&#34;&#34;.  
  No C or C hydrocarbons were detected in the reactor effluent.  
 EXAMPLE VIII A 7.50 g sample of&#39; alumina was placed in a reactor and treated with trifluoromethanesulfonic acid with helium purge until the system showed a weight gain of 2.03 g, corresponding to the depostion of 0.0135 mole of CF SO H on the alumina. The alumina and CF SO H composite contained 21.3 weight percent CF SO H based on the total weight of the supported composition.  
  This system was tested for N-hexane isomerization at C and found to be inactive.  
  It will be evident from the foregoing that various modifications can be made to the method of this invention. Such modifications are considered, however, to be within the scope of the invention.  
 What is claimed is:  
  l. A method of isome&#39;rizing paraffin hydrocarbon containing from four to 12 carbon atoms which comprises passing said hydrocarbon in a feedstream into contact with a catalyst consisting essentially of SbF and CF SO H on a solid support in the presence of hydrogen.  
  2. The method of claim 1 in which said feedstream is passed in the gaseous state into said contact and said catalyst is supported on a material selected from the group consisting of fluorided alumina, potassium fluoride on alumina. sodium fluoride, aluminum phosphate, aluminum fluoride, and charcoal.  
  3. The method of claim 2 in which said feedstream is passed into said contact at a gaseous space velocity within the range of from about 5 to about 5,000 volumes per volume of catalyst at a temperature within the range of from about 80C to about 100C at a pressure within the range of from about 0.1 to about 70 atmospheres. hydrogen being present in a molar ratio of from about 0.] to about 100 moles of the paraffin hydrocarbons.  
  4. The method of claim 3 in which n-heptane contained in a feedstream is passed into contact with said catalyst at a temperature of about 24C, about 1 atmosphere pressure, a hydrogen to n-heptane molar ratio of about 16.2 and a gaseous space velocity of about 61 8 volumes of feedstream per volume of catalyst per hour.  
  5. The method of claim 3 in which n-heptane contained in a feedstream is passed into contact with said catalyst at a temperature of about 0C, about 1 atmosphere pressure, a hydrogen to n-heptane molar ratio of about l6 and a gaseous space velocity of about 600 volumesof feedstream per volume of catalyst per hour.  
  6. The method of claim 1 in which said catalyst comprises SbF and CF SO H in an amount within the range of from about 1.0 to about 40 weight percent of the total SbF and CF SO H based on the total weight of the supported composition.  
  7. The method of claim 1 in which said catalyst contains SbF,-, and CF SO H in a total amount of about 15.7 weight percent based on the total weight of the supported composition, the molar ratio of SbF to CF SO H is about 0.94 and the paraffin hydrocarbon is isomerized at a temperature of about 25 C., a pressure of about 1 atmosphere, a gaseous space velocity of about 640 and a hydrogen to paraffin hydrocarbon molar ratio of about 4.9..  
  8. The method of claim 1 in which said catalyst contains SbF and CF SO H in a total amount of about 15.7 weight percent based on the total weight of the supported composition, the molar ratio of SbF; to CF SO H is about 0.94 and the paraffin hydrocarbon is isomerized at a temperature of about 25 C a pressure of about 1 atmosphere, a gaseous space velocity of about 535 and a hydrogen to paraffin hydrocarbon molar ratio of about 16.8.  
  9. The method of claim 1 in which said catalyst contains SbF and CF SO H in a total amount of about 12.9 weight percent based on the total weight of the supported composition, the molar ratio of SbF to CF SO -,H is about 0.88 and the paraffin hydrocarbon is isomerized at a temperature of about 25 C a pressure of about 1 atmosphere, a gaseous space velocity of about 1050 and a hydrogen to paraffin hydrocarbon molar ratio of about 18.0.