BE622258A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 



  "Improvements in the preparation of catalysts and their use for the isomerization of paraffinic hydrocarbons".



   The present invention relates to the preparation of catalysts and to the use thereof for the isomerization of paraffinic hydrocarbons C4 or higher boiling in the gasoline boiling range, that is, that is to say up to 204 C., and this at temperatures ranging up to 240 C., and more particularly for the isomerization of pentanes and / or hexanes.

   The term "isomerization". embraces both the conversion of normal paraffins to isoparaffins and the conversion

 <Desc / Clms Page number 2>

 
 EMI2.1
 dl isoparaffins fines in isoparaffins having a higher degree of branching. Low temperature breakdown of paraffinic hydrocarbons C4 and: above boiling range of gasoline boiling can be achieved with certain 'capacity.
 EMI2.2
 Analyzers contain enantillalu4in, a metal from the plat1n1 group and chlorine.

   A particularly suitable catalyst can be prepared by the process claimed in the applications. British Patent Nos. 30821/60 and 36154/60. The use of the catalyst for low temperature isomerization is re-
 EMI2.3
 sold in British gevet applications. H * 29542/61 and 29543/61.



   The present invention relates to the preparation of catalysts in a manner which, inter alia, gives such catalysts improved activity for low temperature isomerization.
In accordance with the present invention, a process for preparing a catalyst comprises contacting a halogenatable inorganic oxide with a compound of the general formula?
 EMI2.4
 in which X and Y may be the same or different and
 EMI2.5
 are chosen from H, Cle Br, F or SCI # or in which X and Y can together represent 0 or S,

   stupid non-reducing conditions and at a temperature such that the chlorine fixed by the oxide without the production of free inorganic chloride, and then contacting the chlorinated compound with an oxygen-containing gas, at an elevated temperature . This contact with an oxygen-containing gas will hereinafter be referred to as "calcination".



   Inorganic oxide, besides having to be halo-

 <Desc / Clms Page number 3>

   genable under the conditions specified above, should also exhibit the desired physical characteristics for it to be suitable as a hydrocarbon conversion catalyst.



  It is preferably constituted by a refractory oxide selected from groups III to V of the Periodic Table, for example alumina, boric anhydride, silica, titanium oxide or zirconia. Mixtures of two or more inorganic oxides can be used if desired, one of these preferably being alumina. The preferred refractory oxide is alumina. The present invention will hereinafter be described, for convenience, with reference to the preferred inorganic oxide, i.e., alumina.



   Any of the forms of alumina suitable as a base for reforming catalysts can be used, but a particularly preferred form is that derived from an alumina hydrate precursor, wherein the trihydrate predominates. A form containing a major proportion of ss -alumina trihydrate is particularly suitable. A convenient method of preparing alumina is by hydrolysis of an aluminum alkoxide. for example aluminum isopropylate, in an inert hydrocarbon solvent, for example benzene.

   The other conditions being equal, the higher the quantity of chlorine fixed by the alumina, the higher is the activity of the catalyst and since, as mentioned previously, the maximum amount of chlorine that can be added is propor - relative to the surface area, it is desirable that the aluminum has a high surface area, for example greater than 250 m2 / gram, preferably greater than 300 m2 / gram,
The catalyst preferably contains a small proportion, for example less than 25% by weight, of a metal or of a metal compound having hydrogenating activity, selected from groups Via or VIII of the Periodic Table.

 <Desc / Clms Page number 4>

 



  The preferred metal is a metal from the platinum group which can be present in an amount of 0.01 to 5% by weight, ready *. from 0.1 to 2% by weight. The preferred metal of the platinum group is platinum itself.
The hydrogenating metal is advantageously incorporated into the alumina before the treatment with chlorine,
Primafacie,

   the chlorination treatment which has the effect of adding chlorine to certain reactive surface groups with the removal of oxygen atoms should not be required. Any reactions which would require further oxidation treatment and the reason why oxygen treatment is advantageous are not known with certainty.

   However, it has been observed that it is very advantageous if the chlorinating compound contains sulfur (eg when it is thiocarbonyl tetrachloride, CCl3SCl) or that the catalyst contains a platinum group metal. It is therefore assumed that the sulfur present in the chlorinating compound or as impurities in the commercial grades of other chlorinating compounds reacts with alumina or, more particularly, with the metal. of the platinum group to give a catalyst of lower activity. It has also been observed that carbon monoxide can be a product of the chlorination treatment, this oxide being known to be highly chemisorbed by platinum, with blockage resulting from the effective surface area of the platinum.

   This sulfur or carbon monoxide is removed by oxidation in the subsequent treatment phase, which thus increases the activity of the catalyst,
The phase is suitably covered in air, although oxygen or mixtures of oxygen with inert gas (s) can be used, if desired. It has been observed that heating in inert gas alone is not advantageous.

   The temperature used should be significantly lower.

 <Desc / Clms Page number 5>

   Prior to that at which damage to the catalyst can occur (for example, conversion of alumina from this lyser to [alpha] -alumina, or crystallization of the platinum group metal, if such a metal is present) and a suitable overall range is 500 to 1200 F. The preferred temperature range for the calcination phase is 500 to 1000 F., plus par. particularly from 600 to 900 F. The duration of the calcination is preferably at least one hour, suitably being of the order of 1 to 24 hours.



   Other characteristics of the preparation of the catalyst may be as described in UK patent applications Nos. 30821/60 and 36154/60. Thus a particular characteristic is the specific form of chlorination which produces active catalysts. for low temperature conversion.



   The following examples of compounds providing active and inactive catalysts illustrate the particular nature of the compounds used.
 EMI5.1
 
<tb>



  <SEP> compounds giving <SEP> of <SEP> Compounds <SEP> giving <SEP> of
<tb>
<tb>
<tb>
<tb> active <SEP> catalysts <SEP> <SEP> catalysts.-Inactive
<tb>
<tb>
<tb>
<tb> Tetrachloride <SEP> of <SEP> cabone <SEP> (CC14) <SEP> Hydrochloric acid <SEP> <SEP> (HC1)
<tb>
<tb>
<tb>
<tb>
<tb> Chloroform <SEP> (CHCl3) <SEP> Chlorine <SEP> (Ci <SEP> 2) <SEP>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> <SEP> Methylene <SEP> <SEP> (CH2Cl2) <SEP> Methyl <SEP> <SEP> Chloride <SEP> (CH3Cl)
<tb>
<tb>
<tb>
<tb>
<tb> Dichlorodifluoromethane <SEP> (CCl2F2) <SEP> Acetyl chloride <SEP> <SEP> (CH3COCl)
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Trichlorobromomethane <SEP> (CCl3Br) <SEP> Dichloroethane <SEP> (CH2Cl-CH2Cl)
<tb>
<tb>
<tb>
<tb>
<tb> Thlocarbonyl <SEP> tetrachloride <SEP> <SEP> (CCl3SCl)

  
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Tetrachloroethane <SEP> (CHCl2-CHCl2)
<tb>
<tb>
<tb>
<tb>
<tb> Tetrachlorethylene <SEP> (CCl = CCl2)
<tb>
 
In the case of compounds containing elements other than chlorine, carbon and hydrogen, the treatment can add the other elements to the catalyst in addition to chlorine.



  For example, treatment with dichlorodifluoromethane has

 <Desc / Clms Page number 6>

 results in the attachment of both chlorine and fluorine to the catalyst. It has, moreover, been found that catalysts thus prepared are still active for low temperature conversion, and that they may furthermore have other properties resulting from the addition of the other elements. It has also been found that small amounts of halogens (especially chlorine) which may be present in Alpine prior to the chlorination treatment of the present invention not affecting the activity of the catalysts for low temperature conversion.

   Thus, the alumina used may already contain up to 1% by weight of chlorine and / or fluorine, as when, for example, the starting material which is chlorinated by the process. of the present invention is a catalyst normally used.
 EMI6.1
 Used for refirming hydrocarbons from the gasoline boiling range. Preferred compounds providing active catalysts are carbon tetrachloride, chloroform and methylene chloride.



   The compounds covered by the general formula in which X & t Y together form 0 or S are phosgene
 EMI6.2
 and thîophostene,
The amount of chlorine added to the catalyst is preferably in the range of 1 to 15% by weight, the precise amount depending on the surface area as measured by nitrogen absorption at low temperature. It has been found that the maximum amount of chlorine that can be added without formation of free aluminum chloride is proportional to the initial surface area of the catalyst and is about 3 to 3.5 x 10-4 grams / m2. Maximum chlorination is preferred, but lower amounts of chlorine still give active catalysts, a suitable range therefore being 2 x
 EMI6.3
 io-4 to 3.5 x io "h grams / m 2.



  The non-reducing conditions used for

 <Desc / Clms Page number 7>

      the chlorination can be inert or oxidizing conditions, the latter being preferred. A convenient method of setting! contact with the alumina consists in passing a gas stream of the chlorine compound over the alumina, either alone or, preferably, in a non-reducing carrier gas. Examples of suitable carrier gases are nitrogen, 'air or oxygen.



   Non-reducing conditions are essential, since reducing conditions tend to convert the chlorine compound to hydrochloric acid, resulting in an inactive catalyst. The temperature for the chlorination can be 149-593 ° C. The tendency to form free aluminum chloride increases with temperature and therefore care should be taken when using the temperatures: the higher of the reported range, as the temperatures used will normally be above the temperature of volatilization of aluminum chloride. the formation of free aluminum chloride is readily detected by its occurrence in the gaseous reaction products.

   When treating a compound of alumina and a platinum group metal, precautions should also: Be taken to prevent the formation of volatile platinum complexes / the tendency to form such complexes increasing at again with an increase in temperature. When treating compounds of alumina and a platinum group metal, the temperature is preferably 149 to 371 ° C., platinum-on-alumina compounds being more particularly treated at 232 to 316 C. and palladium-on-alumina compounds at 260-343 C.

   The chlorination reaction is exothermic and the temperatures specified are the initial temperatures used. The rate of addition of the chlorine compound is preferably as low as practicable to ensure uniform chlorination and to avoid a rapid increase in the chlorine compound.

 <Desc / Clms Page number 8>

 temperature as a result of the exothermic reaction.

   The rate of addition preferably does not exceed 1.3% by weight of the catalyst. If a carrier gas is used, the flow rate is preferably at least 200 volumes / volume of catalyst / hour, a suitable range being 200 to 1000 volumes / volume / hour. The pressure used is suitably atmospheric pressure.



   The active catalyst is susceptible to hydrolysis in the presence of water and should therefore be stored under anhydrous conditions. Accordingly, the materials used in the preparation of the catalyst should also be free of water.



   Taking into account the supposed mechanism by which the present invention improves the activity of the catalyst, it will be evident that the preparation process is capable of yielding catalysts having improved activity for a number of hydrocarbon conversion reactions. low temperature, especially reactions which are affected by the presence of sulfur and / or reactions which require the platinum group metal, if present, to be in an unsulfurized state.

   However, the preparation process is suitable by. Particularly for catalysts which are employed for low temperature isomerization and the present invention encompasses a process for the isomerization of C4 and higher paraffinic hydrocarbons boiling in the boiling range of gasoline, this process comprising contacting the hydrocarbons in the presence of hydrogen and at a temperature below 400 F. with a catalyst prepared as described above.



   The feed to the low temperature isomerization process is preferably a feed containing a major proportion of pentanes, hexanes, or a mixture of these paraffins. A feedstock containing a pro-

 <Desc / Clms Page number 9>

 
 EMI9.1
 Particularly preferred is ..j'6 serving of bexanol. If only normal paraffins are desired, the feedstock can first be treated to separate normal paraffins from other hydrocarbons, and normal paraffins.
 EMI9.2
 males, 8ont contacted with the ü'1.omari.ation catalyst.



  Such a separation can suitably be effected by so-called molecular tamils.



   The product of the isomerization reaction can further be processed to recover normal unconverted paraffins, which can be recycled to the reaction zone.
 EMI9.3
 i8omerisatlo. Such a separation can also conveniently be carried out by means of so-called molecular sieves.



   The feedstock is preferably free of sulfur, water and aromatic hydrocarbons. It also advantageously has a low content of naphthenic hydrocarbons.



   Isomerization can be carried out under conditions. tiona, in liquid or vapor phases:
 EMI9.4
 Temperature ! 50 * 4GQ F, preferably 150-350 d Atmospheric pressure 2000 lbs / inch because /, 'preferably 225-1000
 EMI9.5
 Space velocity 0.05-10 vol / vol / vol / vol / hour, preferably 0.2-5 Water molar
 EMI9.6
 gene / hydrocarbons OeOI-20 / le preferably 1.5 * 15/1 If desired, chloreric acid or a compo.

   se resulting in the latter under the reaction conditions (for
 EMI9.7
 eg carbon tetrachloride) can be added * to the reaction zone, either directly or by addition to the feedstock or to the hydrogen-containing gas used,
 EMI9.8
 The halhydrized acid is preferably present in an amount of up to 1% by weight of the feedstock.

 <Desc / Clms Page number 10>

 



   The invention is driven by * example. followed.



   Example 1
 EMI10.1
 1. b'itt. \ L ;! . ,,. ± 1 ..!. \ Y'eI 6 ... ft'lt! 30 ml. of a standard rose of platinum and alumina, containing 0 # 17 percent by weight d. platinum and 0 percent by weight chlorine on standard treated alumina from the following Duud.irt:
 EMI10.2
 a) The compound was: dried in a stream of nitrogen at .00 - ,,, for 2 hours. The hourly space velocity of the gas used throughout the treatment was 500 vol # esvoluuc / hour, a downflow operation being used; b) The dried compound was treated with 24 percent by weight (based on the weight of the loaded catalyst) of carbon tetrachloride at 500 F. The carrier gas was nitrogen and was fed to
 EMI10.3
 through a carbon tetrachloride "saturator" at room temperature.

   In this way, the required amount of vaporized carbon tetrachloride passed over the compound in 1 hour; c) The treated catalyst was flushed with nitrogen at 500 F. for an additional hour and then discharged into a dry airtight container. The treatment had given the compound a weight increase of 6 percent by weight. The chlorine content of the fresh treated catalyst was 11.3 percent by weight.
 EMI10.4
 



  2. lrllra.1.n d..qt, J,: se}, l ... ljtli!
30 ml. of a commercial compound of platinum and alumina, containing 0.57 weight percent platinum and 0.81 weight percent chlorine on Illumine, were treated exactly as for Catalyst A.

   At the end of the treatment with carbon tetrachloride, the catalyst was purged with a circulation of dry air (circulation rate of 500 vol / vol / hour).

 <Desc / Clms Page number 11>

 
 EMI11.1
 and the temperature of the catalyst was raised to µ00 * ?, and kept at peepe temperature for 2 hours *. The catalyst was then at room temperature * under Mote and unloaded 44pu an eyeeeee, et4neho at l. 'air, Treatment <tv &ii;

   gave the compound a 7.25 percent weight increase: the 4% chlove content of the fresh treated catalyst was 55% oe4p in. pos, lys eūro Leo dOU4 fltfulyiaugf preoedents were checked for what çoncomo tour acSi-vi-té 4 * tsomérlaatton at low temperature, fatting ima fpasj5 | 0 C6 sau.rr daartxutia, coming from an eabtenre têgo 0 refinery, containing l percent in po ± 4 * 4! * carbon tsdjfyachlotide and iment4clon charge additive, activity test condisioas were yes.

   vanssg rZmf4% $ p² $ I * # 70 * fvmHm 230, .rrsa, u squared Speed 414 twvn 4 | iqutd vct.1'tr tt4çivie0e of the catalyst was checked by the eonvaTilon 4 païgoeu = quO of I # hexUne in 2, 2 -dimè * thyl butane, <!! e <6 'expe4md pge 14 sonentracion (in percent in Table 1 following rdoultate of tests 41 # 0tvt4
 EMI11.2
 ËNËalvteuf Cotweiïm 2,2-diMetbune, '' T 914 çopt, on P: tdo PrQ4% lit Hon stabilized hot; ttpn 12 heimop 18 ho4eon 36 s' 4 them .â.eat.c A? m, 5 20 9.3 1% 4 2405 j & JL, 2, $ 24 5
 EMI11.3
 
<tb>
<tb>
 

 <Desc / Clms Page number 12>

 
 EMI12.1
 These results show that the eze c1nation treatment given to catalyst B brought about an improvement in the cyeauy activity, giving a higher conversion * per passage 4'.nv; on 4% by weight of%)% 4% &%) w% \ M $ m *) compared with 4 with catalyst A.



  30 mt .. of a co = erclal platinum. of.lU1 $: Ln. and 4 <'chlorine, çv Pçm4ne 0,1? weight percent platinum and 088 tm poqp chlprous on prop alumina: 'a) .t! like PQ: - ca..ya'9 '9. In this case, however. |. and: K '$ it: ot led high temperature was carried out under a stream of dry zoce (500 VP / vl) l / J: Jg13'e), the treatment gave ILOU a 4'4' "rating of weight dg composed of 6e7 percent, The chlorine content of ç4p4;, ypo = fresh was 10.5 percent in potdu, s for the toot 4'actvtté of C.t4y, ¯ were 34Qtent pomb44es predicted Po = sailboat 'catalysts A and B of example i, The result: obtained.



  , are dOnA $ 49 following table 2.
 EMI12.2
 



  Cafcal-wBftu * Convert ton to 2,2-jLs! And: hyl! 9u <: $ pet, Cat! FW percent by weight of product 1qu1de not Itab11ilé 6 hours 18 hours 30 hours 36 hours
 EMI12.3
 
<tb>
<tb>
 
 EMI12.4
 C t9 19t5 19 1G
 EMI12.5
 It will be seen that heating the catalyst in
 EMI12.6
 the nitrogen had no interesting effect., the 4ct1vitd of the catsly <'sister being 14 same as for the untreated catalyst A of 10
 EMI12.7
 Example 1.

 <Desc / Clms Page number 13>

 
 EMI13.1
 



  .mJ. l.é8: I!,. n'OdH Ç4t; 65 grams of a commercial compound of platinum and alumina,
 EMI13.2
 comprising 0.17 weight percent platinum and 0.8 !. weight percent chlorine over alumina were charged to a vertical tuber reactor and dried under a stream of nitrogen at 40 liters per hour for two hours at 500 F. 13.6 grams of tetrachloride were added dropwise. of thiocarbonyl (CCl3SCl) to the feed nitrogen stream over a period of 16 minutes and the treated catalyst was then purged with nitrogen for an additional hour.

   With cooling to room temperature, the catalyst was rapidly discharged into a dry airtight container. The treatment resulted in a 7.1 percent increase in the weight of the catalyst. The chlorine content of the fresh catalyst was 11 weight percent and the sulfur content was 0.47 weight percent,
 EMI13.3
 é axa r, d "c",
26 grams of Catalyst D was calcined in a 40 liter per hour air flow at 900 F. for 1 hour and then cooled to room temperature and discharged into a dry airtight vessel. .



  The chlorine content of the catalyst was 9.1 percent by weight, while the sulfur content was 0.33 percent by weight.
 EMI13.4
 



  Ies t d 'aciv.i1; e, de, $} êttf.IW: f !, n ,, ç.l
The conditions of the activity test were the same as for catalysts A, B and C. The results obtained are given in Table 3 below.

 <Desc / Clms Page number 14>

 



  Table 3
 EMI14.1
 l'.lt ".9tiv: ilI :: é d81 C! 1 ;;.! - 1it3!: t: I" tt. ('iÇ.,!
 EMI14.2
 catalyst Conversion to 2.2wddthylbutan ..
 EMI14.3
 
<tb>



  % <SEP> in <SEP> weight <SEP> of <SEP> product <SEP> liquid
<tb>
<tb>
<tb>
<tb> 6 <SEP> hours <SEP> 12 <SEP> hours <SEP> 21 <SEP> hours <SEP> 39 <SEP> hours
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 4.5 <SEP> 3 <SEP> 3
<tb>
<tb>
<tb>
<tb> 15.5 <SEP> 18.5 <SEP> 19.5
<tb>
 
The particular advantage obtained by using the present invention, when the chlorinating compound contains sulfur, will be readily apparent from considering this Table 3.
 EMI14.4
 .v.ENQAJ: 9N?
1.

   A process for preparing a catalyst comprising contacting a halogenatable inorganic oxide with a compound of the general formula:
 EMI14.5
 in which X and Y can be identical. or different. and consist of H, Cl, Br, F or SCl, or in which X and
Y together form 0 or S, under non-reducing conditions and at a temperature such that the chlorine is bound by the oxide without production of free inorganic chloride, and then contacting the chlorinated compound with an oxygen-containing gas at high temperature.


    

Claims (1)

2. A process according to claim 1, wherein the inorganic oxide is alumina or an oxide mixture containing alumina. EMI14.6 3. A process according to Mvendic & t: iona * 1 or 2e in which the catalyst contains a small proportion of a metalline or a metallic compound having a .hydrogenating activity, <Desc / Clms Page number 15> EMI15.1 Selected from the groups Via U VZZI of the Periodic Table * 49 A method according to claim 3 wherein the catalyst contains 9.01 h 5% by weight of a metal 3 * V platinum group. 5. A process according to any of the annealing dications 1 to zut, wherein the oxygen-containing 1 *; 84Z is 8 'air. Ilary 6. A method which sucks any one of claims 1 to 1 in which the contact value with an oxide-containing gas is d t1! at 1900.0?, preferably bzz from 500 to 1000 * F .. sunt {y any one of reven ** process according to any one of revono Ltn pxaclb ni na qua.apnqus das dieatiens 1 z 6, wherein the chlorination rate is ", from 300 to 1., OQaF. The process follows: an <: evendaion dana A process according to claim 7t wherein the catalyst contains et4j from the platinum group and the temperature is 300 to OCppi 9. A process for the Èi'la0roeri * ation of paraffinic hydxocarbons C and 6 egl boiling in the range cri boiling gasoline, including contacting the hydrocarbons in the presence of hdxg xi a temperature below 40 "'p with a p-catalyst by the process of any one of claims ff | k 8. 10. A process according to claim 9, wherein the feedstock contains a major proportion of pentanes and / or hexanes. 11. A process according to claims 9 or 10, wherein the temperature of temperature is 50 to 400 "F. and the pressure is from the spherical premiston to 2000 pounds per square inch. Square inch. 12. A process or claim 11 in which the temperature is 150 and the pressure is <Desc / Clms Page number 16> 223 to 1000 pounds per square inch. 13. A process for preparing a catalyst, as described above, in particular in Examples. 14. A process for the isomerization of paraffinic hydrocarbons C4 and higher, boiling in gasoline boiling Se = *, as described above, in particular in the examples,