CA1212700A - Process for production of diesel fuel - Google Patents

Abstract

ABSTRACT

Gasoline capable of further processing into diesel fuel is produced by catalytic conversion of lower olefins, using a zeolite catalyst which has been modified by substituting a significant portion of the cation sites thereof by basic cations. A preferred catalyst comprises a zeolite and a binder, said catalyst containing at least 0.2% by weight of exchangeable basic cations. The gasoline so produced is readily converted by contact with a Friedel Crafts catalyst into a hydrocarbon product having a significant fraction boiling in the distillate range.

Description

Process for production of diesel fuel This invention relates to the production of 5 distillate (diesel fuel).
In accordance with the invention it has been unexpectedly found that gasoline feedstocks prepared in a particular manner can be readily processed into a hydrocarbon product with a significant fraction boiling 10 in the distillate range.
The said gasoline feedstocks are prepared by conversion of light olefins, using a zeolite catalyst that is modified as hereinafter described.

~ . '~

T The subsequent processing of the said gasoline feedstocks in accordance with the invention may be carried out using a conventional Friedel-Crafts catalyst.
The oligomerisatlon of light olefins over acid 5 catalysts is well known - see e.g. Kirk-Othmer "Encyclopaedia of Chemical Technology" 3rd Edition 1978 John Wiley - Vol.4. p.362 - this gives a material useful for gasoline blending stock. Higher severity oligomerisation to materials in the distillate range is 10 possible, but the product, because of much skeletal isomerisation and branching, suffers from low cetane number e.g. tetra-iso-butylene-olefin oligomer of isobutylene, cetane No. 15, compared with n-hexadecane (cetane), cetane No. 100.
U.S. Patent Nos. 3,894,106, 4,062,~05 and 4,052,479 disclose the conversion of alcohols and ethers to higher hydrocarbons by contact with a zeolite catalyst having a silica to alumina ratio of at least 12 at about 260 to 450C. The preferred zeolite catalysts have 20 crystal densities which are not substantially below 1.6 grams per cubic centimeter. These special catalysts are exemplified by ZSM-12* as in West German Offenlegungsschrift No. 2,213,109, ZSM--21*and certain modified naturally occurring zeolites. The synthetic 25 zeolites made using an organic cation are preferred.
Aromatization of hydrocarbon feedstocks over zeolites is well known. U.S. Patent No. 3,760,024 discloses an aromatization process for a feedstock comprising C2 to C4 paraffins and olefins comprising 30 contacting such a feedstock with crystalline aluminosilicates of the ZSM-5*family. U.S. patent No.
3,756,942 discloses contacting a feeds-tock having a boiling range of C5 to about 250F wi-th a crystalline aluminosilicate zeolite of the ZSM-5 type, and US patent 35 4,150,062 d~scribes an invention which relates to * Trade Mark improved processing of light olefins of from 2 to 4 carbon atoms to product comprising high oc-tane gasoline components. The process comprises contacting the olefin feedstock in the presence of co-fed water with a catalyst 5 comprising a zeolite characterized by a silica/alumina molar ratio of at least 12.
The crystalline aluminosilicate zeolites used in the catalyst composition of the process of this latter invention are referred to generally as -the ZSM 5 family, 10 or as behaving like ZSM-5, and include ZSM-5, ZSM-ll*
ZSM-12, ZSM-35*and ZSM 3~.
Olefin oligomerisation over zeolite of the ZSM-5 family such as ZSM-12 has also been described in US
Patent 4,254,295. This disclosed a process for the 15 selective oligomerization of linear and branched chain C2 to C12 olefins and comprised contacting the olefins, in the liquid phase, with a ZSM-12 zeolite at temperatures from about 80F to about 400F. It was found that the process provided selective conversion of the olefin feed 20 to oligomer products with high selectivity, the product containing little or no light cracked products, paraffins, etc.
Light olefins can be synthesised from alcohols such as methanol using zeolite catalysts similar to those 25 described above, as in for example US Patent 4,025,576.
This shows that a feed comprising one or more compounds selected from the lower monohydric alcohols with up to four carbon atoms, and their simple or mixed e-ther derivatives, at subatmospheric partial pressure, is 30 completely converted to a mixture comprising mainly light olefins, by contact with a particular type of crystalline aluminosilicate catalyst.
Although it is a generally accepted fact that zeolites in the alkali metal form are of substantially 35 less catalytic activity, in some cases completely * Trade Mark ~lZ3L%7~

inactive, the conversion of methanol over alkali metal modified zeolites has been described in US Patent 3899544. For conversion of alcohols and ethers to higher hydrocarbons by zeolite catalysts, if the zeolite is 5 fully exchanged so tha-t its ca-tion content is substantially alkali metal, it loses most of its activity to catalyse this reaction. Such high alkali metal content zeolites do however retain activity for sorne catalytic roles, no-tably the dehydration of alcohols to 10 ethers.
When most of the alkali metal is exchanged out of the zeolite and replaced by acid sites, (for example by ammonium exchange followed by calcination to liberate ammonia and leave a proton within the zeolite, or as in 15 the case of acid stable zeolites such as ZSM-5, by direct exchange in acidic media) the catalyst is extremely active for converting alcohols and/or ethers to higher hydrocarbons. ~or example, in the conversion of methanol to hydrocarbons in contact with an H-ZSM-5 zeolite 20 catalyst from which most of the alkali metal (usually sodium) has been removed, the hydrocarbon yield at 100%
feed conversion is consisten-tly about 44 weight percent, based upon methanol fed (i.e. little conversion to dimethyl ether and other oxygenates). Where none of the 25 alkali metal has been removed the hydrocarbon yield is zero.
It is an object of the present invention to provide an improved process for the conversion of light olefins into a hydrocarbon stock a substantial portion of 30 which boils in the distillate range with only a minor portion boiling in the gasoline range.
In accordance with and fulfilling this object, one aspect of this invention resides in the discovery -that when the conversion of lower olefins, by which we 35 mea~ C3-C6 olefins and mixtures thereof, to higher ~ 6 hydrocarbons, particularly hydrocarbons boiling in the gasoline boiling range, e.g. C5 to 196C, is carried out over a zeolite modified in a particular manner, the resulting gasoline can be readily processed, using for 5 example a Friedel-Crafts catalyst, into a hydrocarbon stock with a significant fraction boiling in the distillate range. The conversion is carried out at about 100C to 450C, preferably 300 to 450C, up to about 50 atmospheres, and about 0.5 to 50 liquid hourly space lO velocity.
The catalyst modification which makes possible the improved operation described herein is to ensure that a significant portion of the cation sites of the aforementioned zeolite is occupied by basic cations, 15 notably Lewis or Bronsted bases such as elements of Group Ia, IIa or Va of the Periodic table. Specific ca-tions which have been found to be particularly useful are those which contain sodium, potassium, calclum, nitrogen and phosphorus, either alone or in appropriate cationic 20 complex form.
The zeolites used as catalysts are usually obtained from a composition containing an organic cation.
After initially producing the zeolite crystal structure desired with its original organic and alkali metal 25 cations, it is dried, and then may be directly calcined, in which case the organic cations are removed by oxidation to produce a zeolite containing alkali metal cations. The alkali metal can be exchanged ei-ther with other metal ions or with ammonium ions or both. Where 30 acid sites are desired ammonium cations are used. The ammonium form oE the zeolite, upon calcination to remove ammonia, leaves the hydrogen form of the zeolite. The order of exchange and calcination is variable with ~ 2~ f~7~

several different sequences of operation reported to give special results for particular purposes well known in the art.
The catalyst of this invention can be prepared 5 by converting all of the cationic sites to the alkali metal form and then exchanying a proportion of the alkali metal cations for acid or other "active" cations.
Alternatively an acid form zeolite can be subjected to exchange with appropriate alkali metal moieties.
Another method o~ obtaining the catalyst of.
this invention is to mix the hydrogen (acid) form of the zeolite with a solid matrix or binder which has available alkali-cations. Although we do not wish to be limited by any theoretical or postulated mechanism for the observed 15 beneficial results, we observe that, after the influence of calcination, the composite ca-talyst performs as if a portion of the zeolite component had been exchanged by alkali metal.
Another method of obtaining the catalyst of 20 this invention is to use the as-made zeolite; that is, a ~eolite containing both organic and alkali metal cations, and calcining the zeolite (with or without binder, as powder or pellet) so as t.o remove a portion of the organic cations. I-t will be appreciated that the 25 relative amount of organic and alkali-metal cation will be dependent on such things as the nature of the organic moie-ty, the relative concentrations of organic and alkali-metal in the synthesis-gel and to some extent the silica-alumina ratio of the zeolite, the rela-tive 30 proportion of which can be adjusted by methods well known to -those skilled in the art. It will also be appreciated that in this embodiment, the catalyst is not subjected to ion exchange after synthesis (see examples 13, 20, 27 and 32 below).

7~

Accordingly, the invention provides a process for conversion of lower olefins to hydrocarbons boiling in the gasoline boiling range, characterised in that the lower olefins are converted by contact with a zeolite 5 catalyst which has been modified by substituting a significant portion of the cation sites thereof by basic cations, whereby the gasoline produced is capable of further processing into a hydrocarbon produc-t with a significant fraction boiling in the dis-tillate range.
In a preferred embodiment of the invention ~he catalyst comprises a zeoli-te and a binder, said catalyst containing at least 0.2%, preferably at least 0.3%, of exchangeable basic cations, determined as oxide, on the total weight of the catalyst.
The catalyst may comprise up to 90% by weight binder, such as bentonite or alumina, but is preferably within the range of 25% to 75~.
The zeolite is preferably of the ZSM family, having an A12O3 content of at least 1~ by weight. Whilst 20 the lower limits of alumina, and hence alkali metal, in the zeolite are determined by the need for sufficient ca-talytic activity, the upper l.mits are determined by the maximum level of zeolitic alumina that can be tolerated by a given zeolite. For example, it is well 25 known that ZSM-5 will typically have maximum alumina contents at about 4.5% by weight; in -this case the maximum alkali-metal con-ten-t would correspond -to about 80% of this value, calculated on a mola.r basis. Other zeoli-tes can have much higher alurnina contents, so that 30 the corresponding maximum alkali content would be proportionally higher.
Those skilled in the art will realize that, on the basis of the above, the ca-talys-t (zeoli-te plus binder) of the present inven-tion preferably has 20% of ~2~7~
g the exchangeable basic cations on a molar basis relative to the alumina content of the zeolite. More preferably the figure is 30%.
In a further preferred embodiment of the 5 invention a process for production of diesel fuel comprises the following steps:-(a) converting lower olefins at temperatures between about 100 to 450C. preferably be-tween 260 to 450C and more preferably between 300 and 450C, pressures up to about 50 atmospheres, and LHSV of about 0.5 to 50hr 1, in contact with a zeolite catalyst which has been modified by substituting a significant portion of the cation sites thereof by basic cations, preferably a catalyst comprising a zeolite and a binder, said catalyst containing at least 0.2%, and preferably at least 0.3~, of exchangeable basic cations, determined as oxide, on the total weight of the catalyst, to produce a first hydrocarbon product containing hydrocarbons boiling in the gasoline boiling range' (b) converting the said first hydrocarbon product by contact with a Friedel-Crafts ca-talyst into a second hydrocarbon product a substantial portion of which boils ln -the distillate range with only a minor portion boiling in the gasoline range.

7;~

Preferably the second hydrocarbon produc-t comprises at least 40gO~ and more preferably at least 50 by weight distillate boiling at ~235C, and preferably less than 50%, and more preferably less than 40%, by 5 weight gasoline.
It has been noted that a zeolite catalyst of this invention has alkali metal and acid cationic sites.
It may also have other cationic sites, such as hydrogenation/dehydrogenation components, incorporated 10 for given purposes. These other sites are to be considered as part of the acid site group and are not to be considered as replacing alkali metal cation moieties.
These additional components can be incorporated with the zeolite catalyst by impregnation, vapor deposition or 15 exchange, as may seem desirable.
It has been ascertainecl that the catalysts of this invention are capable of converting alcohols such as methanol into an olefinic gasoline, but the catalyst deactivates quickly, e g. over a period of about five 20 hours on line, making practical use of these ca-talysts for alcohol conversion difficult. Surprisingly, it has been found that 012fin conversion over the ca-talysts continues to give useful yields of liquid product for much longer periods, e.g greater than thir-ty hours on 25 line before reactivation, by for example air-calcination, is required.
The present invention has further ascertained that the product hydrocarbon stock produced from olefins over alkali-metal containing zeolites such as described 30 above can be easily converted by trea-tment with a Lewis acid catalyst such as aluminium chloride into a product rich in distillate fraction. The catalyst particularly useful for the conversion of the hydrocarbon s-tock can be termed a Friedel-Crafts catalyst, a detailed description 7~

of which can be found in "Friedel-Crafts and Related Reactions" G.A. Olah (ed) Vols 1-4, Interscience, 1953-65.
The invention will be further illus-trated by 5 the following non-limiting examples.

Example 1 This example describes the synthesis of ZSM 5 with a high sodium content.
Aluminium wire (2.51g) was dissolved in sodium 10 hydroxide solution (15.2g in lOOg water). The solution was then added to colloidal silica (667g of Ludox HS40 (trade mark), 40% SiO2) and stirred. Tetra-propylammonium bromide (147.8g) in water (lOOOg) was then added and the whole vigorously stirred to a homogeneous 15 gel. The gel was stiffened by the addition of sodium chloride (250g). The zeolite was crystallized from the mixture by heating the gel in an autoclave to 175C, with stirring, for 16 hours. The zeolite was obtained from the mother liquor by filtration and washing with 20 distilled water. The as-made zeolite was then washed with 2M hydrochloric acid and then calcined (500~ in moist air for 16 hrs.). The product analysed at ].~6%
A1203 and 1.7~ Na20 (i.e. all Al expressed as ~-t ~ A1203 and all Na expressed as Wt ~ Na20).

25 Example 2 This examp].e describes a further synthesis of high sodium con-tent ZSM-5.
The zeolite was prepared in an analogous manner -to that described in Example 1 e~cep-t tha-t -the weigh-ts of 30 active componen-ts were: aluminium wire (1.28~) sodium hydroxide (7.5g); colloidal silica (336.6g), tetra-n-propylammonium bromide (73.9g). The same quantities of 7~

water and sodium chloride were used as for Example 1.
After acid washing, calcination and drying, the product was analysed at 1.18% A1203 and 0.3~ Na20.

Example _ This describes the conversion of propylene over high sodium ZSM-5.
Samples of zeolite from examples 1 and 2 were mixed with bentonite (33~ by weight bentonite) and water, then extruded. The extrusions (3mm) were dried and 10 calcined at 500C. They were then charged (72g plus 40g of inert alumina spheres) into a downflow tubular reactor. Propylene was passed at 36 litres/hr over the catalyst at about 300C and the liquid products condensed (123g of liquid). The liquid was analysed by gas-15 chromatography (12.5m, SP2100, fused silica column) and asimulated distillation profile obtained. The results are shown in Table 1 and indicate the product consists predominantly of material boiling in the gasoline-range.

Table 1 Simulated Distillation Profile of Liquid Produc-t from Example 3.

Fraction _imulated Boiling Range Wt %
~gasoline <196C 93.4 jet-fuel 196 - 235C 4.3 25 middle distillate 1 235 - 317C 1.7 middle distillate 2 >317C 0.7 Example 4 This describes the conversion of the liquid product obtained in Example 3 into material boiling in 30 the distillate range.

7~

The liquid (30g) and anhydrous aluminium chloride (lOg) were refluxed (for 3 hours). The mixture was then hydrolysed by shakiny with water (approx. 200 cc) and the hydrocarbon fraction obtained by separation 5 and filtration. The liquid product was subjected to the same chromatographic analysis as in Example 3; the results of the simulated dis-tillation profile are shown in Table 2 and clearly demonstrate the increase in boiling points obtained by AlC13 treatmen-t.

10 Table 2 Simulated Distillation Profile of Liquid Product from Example 4.
.
Fraction Simulated Boiling Range Wt ~
gasoline <196C 28.6 1~ jet-fuel 196 - 235C 12.9 middle distillate 1 234 - 317C 27.8 middle distillate 2 >317C 30.6 __ _xample 5 This describes the conversion of propylene over 20 acid ZSM-5 (H-Z5M-5).
H-ZSM-5 was obtained by a preparation similar to that described in Example 1. The final product was converted into a low sodium form by further washing the product with 2M hydrochloric acid, then giving the 25 product a further calcination. The product was fabricated into extrudates (as described in Example 3) and used -to convert propylene (25L/hr over 47g of catalyst at approx. 350C). The resulting liquid product (62g) was subjected to the same gas-chromatographic 30 analysis as described in Example 3. The results are ~2~7~

shown in Table 3 and illustrate the product had a very similar boiling-point profile as the product of Example 3.

Table 3 Simulated Distillation Profile of I.iquid Product from Example 5.

Fraction Simulated Boiling Range Wt %
gasoline ~196~C 91.6 jet~fuel 196 - 235C 5.7 1 ¦ middle distillate 1 235 - 317C 2.2 middle distillate 2 317C 0.5 . _ I
Example_6 The liquid product of Example 5 was then treated with aluminium chloride as hydrolysed as 15 described in Example 4. The resultant liquid was again analysed by gas-chromatography and the simulated distillation profile obtained (Table 4). Comparison of Tables 4 and 2 demonstrates the ineffectiveness of the Friedel-Crafts treatment in Example 6 in tha-t the major ~0 portion of the product remains in the gasoline boiling-range.

Tab]e 4 Simulated Distilla-tion Profile of the Product obtained from Aluminium Chloride Treatment of Liquid 25 Product obtained from Example 5.

Fraction Simulated Boilinq Range Wt %
_ _, ..
gasoline 196 C 76.9 jet-fuel 196 - 235C 5.7 middle distillate 1 235 - 317C 4.6 30 middle distillate 2 317C 12.8 ~z~

Examples 7-13 These examples describe the characteristics of catalysts used in following examples.

Table 5 5 ~ ~ Zeolite _ Analysis Catalyst Analysis (a) ~ample ~Codo 5102/A1203 ~ si~2 /~]23 /3~2 %~e23 7 A1 95 86.0 7.4 0.56(b) 8 A2 40 80.8 8.0 0.88(b) 9 A3 95 85.9 7.6 0.681.33 A4 40 78.5 8.0 1.311.19 1511 A5 95 77.5 6.4 1.181.08 12 A6 9S 8'~.07.0 1.281.21 13 A7 = .2 1.501~26 (a) analyses, on a weight basis, of a 2/1, zeoli-te/bentonite extrusion, expressing all metal as its oxide.
(b) not determined.
(c) molar.
(d) impurity in bentonite.

The zeolites were synthesised by 25 crystallisation of silica/alumina gels usiny tetra-n-propylammonium cation as organic templating cation. They

2~

were modified to differing sodium content as illustrated in Table 5. In examples 7 and 3 the catalysts were made from the "as-made" zeolites by ion-exchanging with hydrochloric acid (2M) and calcining the catalyst twice.
5 The sodium content of the zeolite before fabrication was very lol,l. The zeolites were then mixed with bentonite (2/1, w/w) and formed in-to extrusions. For catalysts in Examples 9, 10, 11, the zeolites (from separate syntheses) were ion-exchanged and calcined only once.
10 The catalyst of Example 12 was the same as Example 11,.
but was further washed with ammonium/sodium ion solution The catalyst of Example 13 was the "as-made" zeolite i.e received no ion-exchanges or calcinations before mixing with bentonite and forming into a catalyst. This 15 illustrates the effect of leaving the tetra-n-propylammonium cations in the zeolite.

Examples 14-20 These examples illustrate the use of catalysts of Examples 7-13 to prepare gasolines of varying olefinic 20 con-tent. Propylene, at 1 atm. pressure, was passed over a packed bed of the catalyst held at 300C. After cooling to ambient the product gasolines were collected and the quantity of aliphatics present determined by NMR
and GLC, and the gasolines characterised by RON (clear).
25 The results are given in Table 6.

Table 6 Example Catalyst WHSV Max Temp Liquid I(A/O) ~/Oaliphatics RON
(hr_l) (C), (a) Yield (clear) __ (b) (c) 14 Ex7 2.4 483 0.509.0 41.3 100.0 Ex8 1.5 455 0.474.7 53.5 98.6 16 Ex9 2.2 445 0.490.5 79.5 95.5 10 17 Ex10 1.6 449 0.591.7 80.9 96.8 18 Exll 2.6 410 0.470.19 81.5 95.5 19 Ex12 2.8 433 0.340.20 83.3 92.3 Ex13 0.9 383 0.580.34 75.2 _ 15 (a) hot spot temperature.
(b) gg 1 of propylene converted.
(c) Ratio of aromatic proton intensity/olefin proton intensity by lH N.M.R.
(d) from G.L.C.

Examples 14 and 15 illustrate that extensive exchange of the zeolite to remove alkali-cation results in higher a.romatic content gasoline than if the zeolite is ion-exchanged and calcined just once (Examples 16-18).
Example 19 illustrates tha-t excessive back exchange with 25 sodium ions may reduce unduly the activity of the catalyst (liquid yield ~0.34 gg propylene fed).
Example 20 illustrates that "as-made" catalysts which may retain significant portions of alkyl qua-ternary cations ~2~,~7~

and/or their decomposition products are effective catalysts. It should be noted -that all products were acceptable as gasolines of high (>90) RON (clear).

Examples 21-27 These illustrate the conversion of the gasolines described in Examples 14 20 into products boiling greater than 196C.
Samples of yasolines described in Examples 14-20 were treated with anhydrous aluminium chloride under 10 reflux conditions. After three hours the reaction was stopped by adding water. The organic phase was separated and analysed by a G.L.C. simulated distillation technique and by N.M.R. The results are given in Table 7.

Table 7 Product s.P.
(simulated distillation) 20 ~xample Produc I(A/O) ~196 196-235 235-317 C

21Ex 14 6.8 69.4 10.0 9.3 11.3 22Ex 15 2.7 51.2 10.0 16.3 22.5 23Ex 16 0.4 49.1 8.4 20.2 22.4 24Ex 17 0.4 4501 17.0 22.4 15.6 25 25 Ex 18 0.3 25.6 12.2 29.6 32.6 26 Ex 19 0.4 33.6 8.7 25.1 32.6 27 Ex 20 0.3 3~.3 11.1 27.0 31.6 7~

Although all the gasoline feedstocks gave some products higher in boiling point than gasoline (<196C), the produc-ts of Examples 21 and 22 in which the zeolite had received multiple ion exchange and calcination were 5 inferior to the other products. Although Example 23 is similar to 22 t the performance in the former case is preferred because more product in the middle distillate range (235-317C) is obtained. These examples serve to illustrate that good yields of middle dis-tillate and 10 higher products can be obtained from propylene by using catalysts of high exchanyeable alkali-content, and tha-t excessive removal oE the alkali by ion-exchange hinders the production of distillate boiling products (Examples 21 and 22).
From the above it will be evident -that preferred catalysts are represented by Examples 1, 2, 9, 10, 11 and 13.

Examples 28, 29 These examples serve to illustrate the effect 20 of on-stream time on the conversion of propylene to gasoline over the alkali-metal containiny zeolites.
The results are given in Table 8. As can be seen the performance of both catalysts changes with time-on-stream, but the preferred catalyst (Example 29) 25 is that one containing a zeolite with only one ion-exchange treatment and where the change in performance is less severe. Bo-th catalysts produce high yields of aromatics at early -time on line but for the preferred catalyst, this aroma-tic yield rapidly falls to a very low 30 value within 340 min. on-stream-time.

~;27~

Table 8 Example 28 Catalyst Ex-8, WHSV = l.lhr ._ Time Max TempLiquid I(A/O~ %Aliphatics on- (C) Yield 5 stream (gg 1 propene (min) converted) _ ~
190 455 0.41 17.6 33 309 4~9 0.51 6.1 46 509 (424) 0.57 1.8 49 10751 433 0.53 1.2 60 996 452 0.39 0.8 67 1212 447 0.41 0.6 66 _ Example 29 Catalyst Ex-10, WHSV - 1.6hr . _ .
Time Max Temp Liquid(a)I(A/O) %Aliphatics 15 on- (C) Yield stream (gg 1 propene (min) conv~rted) . _ _ _ _ 180 449 0.54 ~ 8.6 45.0 340 437 0.65 0.4 71.0 20475 423 0.65 0.1 90.0 610 424 0.64 0.2 83.5 820 416 0.61 0.3 87.~
920 413 0.59 0.3 90.6 1105 398 0.49 0.01 89.4 25 1260 3~2 0.47 0.01 90.8 .~ . . ..

7~

Examples_30, 31 These illustrate the conversion of butylenes over the preferred catalyst as described in ~xample 9.
5 The results are given in Table 9. These results show that light olefins such as l-butene and isobutene can be converted to olefinic gasolines over the alkali-me-tal containing catalysts.
Experiments using ethylene failed to give 10 significan-t yields of gasolines under similar conditions.

Table 9 Example 30 l-Butene Feed WHSV = lhr 1 15 Time On Line Ternp ~ Liquid Yield I(A/O) %Aliphatics (min) (C) (gg-l l-butene I converted) 180 366 .64 0.5 76.4 20 335 361 .76 0.2 74.6 470 359 .77 0.2 76.4 528 358 .73 0.1 79.1 718 354 .78 0.1 77.7 7~

_ Example 31 Isobutene Feed WHSV = lhr 1 Time On Line ¦ T C ¦ Liquid Yleld I(A/O) %Aliphatics (min) (max) (gg isobutene converted) _ 150 348 .64 0.4 70.9 290 344 .73 0.2 75.8 445 342 .73 0.1 78.6 10595 340 .72 0.1 78.4 760 340 .80 0.1 77.7 970 340 .71 0.08 78.2 1270 340 .78 0.07 80.4 1425 325 .64 0.07 80.1 , ~ :
15 Example 32 This illustrates the beneficial use of potassium as alkali-metal to influence the performance of the zeolite.
A catalyst was formed in a si~ilar manner to 20 that described in Example 13 except in that the starting gel contained only potassium as the alkali-metal.
Reaction with propylene, in a similar manner to that described in Example 20, gave a gasoline of very low aromatic content (I(A/O) <0.1) wi-th a RON (clear) of 25 ~6.1.

Examples 33 and 34 These illustrate -that alkaline earth ca-tions of Group IIa beneficially produce an olefinic gasoline but those of Group IIb give an aromatic gasoline.

~2~;~7~

Zeolites similar to those described in Examples 7 and 1 were treated with calcium and zinc exchange solutions respec-tively. Af-ter exchange and forming into extrusions (2/1, zeolite/bentonite) the catalysts 5 contained 3.50% CaO and 0.77% ZnO respectively.
Propylene was passed over the catalysts in a similar manner to that described for Example 14-20. The results are given in Table 10.

Table 10 lC Exchange WHSV TC ~ =
ExampleCatlon (hr~l) (max) Yield( ) I(A/O) 33Ca 0.9 412 0.50 0.36 34Zn 1.84 267 0.42 0.63 466 0.22 16.7 15 (a) g g 1 of propylene fed, average value.

The calcium treated zeoli-te (Example 33) gives an olefinic gasoline with acceptable yield. The zinc treated catalyst (Example 34) appears only useful at low temperatures, higher temperatures giving higher yields of 20 aromatics.

Examples 35-42 These examples serve to illustrate that olefinic gasolines produced by the preferred catalysts can be converted, by a variety of catalys-ts, into a 25 product containing significant quantities of ]cerosene, distillate and fuel-oil. The results are shown in Table 11, where an olefinic gasoline feed was obtained from propylene using the catalyst described in Example 9.

7~

Erom the results, aluminium chloride, boron trifluoride on silica-alumina, aluminium chloride on silica-alumina, and phosphoric acid on kieselguhr gave reasonable yields of products higher in boiling point S than gasoline. Hydrogen fluoride treated silica-alumina gave somewhat lower yields, as did the zeolite of Example 42.
These results illustrate that dis-ti].la-te range products can be produced from the olefinic gasolines 10 described above by a wide variety of solid-acid catalysts, as well as homogeneous catalysts such as aluminium chloride.

7~

T ab l e_ Treatment _ ~ it lated Di stillation _ Gasoline Kerosene Distillate Oil _ _ _ _ Starting Nil 91.6 3.4 3.6 1.4 Gasoline Ex 35 ~lC13 Reflux 45.5 13.8 32.5 8.2 180 mins.
25 wt.%
AlC13 Ex 36 BF on 130 C 55-.3 11.5 21.4 11.8 Si13ica- overnight alumina 25 wt.%
catalyst Ex 37 BF3 on 130 C 62.6 11.5 17.1 8.9 Silica- overnight alumina 12.5 wt.%
catalyst Ex 38 AlC13 on 130 C 68.6 10.4 13.9 7.2 silica~ overnight alumina 25 wt.%
catalyst 25 Ex 39 H3P04 on 130C 80.0 10.6 7.6 1.8 kieselguhr overnight 25 wt.%
catalyst Ex 40 HF on 130C 84.87.4 5.6 2.3 silica- overnight alumina 25 wt.%
catalyst _ 7~)~

Table 11 (continued) Catalyst Treatment Simulated Distillation Gasoline Kerosene ~ t~ Fue _ Ex 41 BF3, HF 130 C 87.1 6.1 4.6 2.3 on silica- overnight alumina 25 wt.%
catalyst Ex 42 Exa~ple 7 130 C for 87.3 5.0 4.8 2.
5 hours catalyst _ _ 7t:~

Example 43 -This example illustrates tha-t methanol conversion over the preferred catalyst is unstable, and conversion can only be main-tained for a ].lmited on-S stream-time.
A down flow reactor was charged with 70g of a catalyst formed as in Example 9. Methanol (at W~ISV
~2.1hr 1) was passed over the catalyst at 360C. A hot-spot developed near the top of the bed, reaching 564C.
10 After five hours on stream the hot spot had travelled to the bottom of the bed indicating deactivation of the catalyst. It is well known that conversion falls to very low levels when -the hot spot is lost from the catalyst bed, hence the effective useful on-stream-time for 15 methanol conversion was only 5 hours.

Example 44 This example illustrates the conversion of dimethylether (DME) over a high sodium catalyst.
Dimethylether (1000 ml min 1) was passed over a 20 catalyst (70g) as described in Example 43. The details of the conversion are given in Table 12.

~L2~L~7~

Table 12 -~ _ ._____ . , Time onSet Temp. Max %DME in line (C) Temp gas phase Hot spot position (min (C) products 5 cumulative) (a) _ 350 547 nil top of bed 300 350 572 1.8 bottom of bed 420 400 566 6.9 middle of bed 660 475 579 1.1 bottom of bed 750 475 557 54.4 bottom of bed (a) Liquid products condensed out at ambient temperature.

These results illustrate tha-t -the preferred catalysts, although capable of converting dimethylether, can only do so for a llmi-ted -time on-line and that increasing -the bed temperature fails to overcome the activity decay. This is in con-trast to conversion of 20 ligh-t olefins, propylene, butylene etc., which are able to undergo conversion for much longer periods before regeneration is required~

It will be clearly understood that the invention in its general aspects is not limited to the specific details referred to hereinabove.

Claims (18)

CLAIMS:

1. Process for conversion of lower olefins to hydrocarbons boiling in the gasoline boiling range, characterised in that the lower olefins are converted by contact with a zeolite catalyst which has been modified by substituting a significant portion of the cation sites thereof by basic cations, whereby the gasoline produced is capable of further processing into a hydrocarbon product with a significant fraction boiling in the distillate range.

2. Process according to Claim 1 in which the said basic cations are selected from one or more elements of Group Ia, IIa or Va of the Periodic Table.

3. Process according to Claim 2 in which the basic cations are selected from one or more of sodium, potassium, calcium, nitrogen and phosphorus, either alone or in appropriate cationic complex form.

4. Process according to any one of Claims 1 to 3 in which the zeolite catalyst includes alkali metal and acid cationic sites.

5. Process for production of diesel fuel, characterised in that lower olefins are converted into gasoline by the method of any one of Claims 1 to 3 and the gasoline is converted by contact with a Friedel-Crafts catalyst into a hydrocarbon product having a significant fraction boiling in the distillate range.

6. Process for production of diesel fuel, which comprises converting a gasoline produced by the process of any one of Claims 1 to 3 by contact with a Friedel-Crafts catalyst to produce a hydrocarbon product a substantial portion of which boils in the distillate range with only a minor portion boiling in the gasoline range.

7. Process for conversion of lower olefins to hydrocarbons boiling in the gasoline boiling range, characterised in that the lower olefins are converted by contact with a catalyst comprising a zeolite and a binder, said catalyst containing at least 0.2% by weight of exchangeable basic cations, determined as oxide, on the total weight of the catalyst, whereby the gasoline produced is capable of further processing into a hydrocarbon product with a significant fraction boiling in the distillate range.

8. Process according to Claim 7 in which the catalyst contains at least 0.3% by weight of exchangeable basic cations, determined as oxide, on the total weight of the catalyst.

9. Process according to Claim 7 in which the said basic cations are selected from one or more elements of Group Ia, IIa or Va of the Periodic Table.

10. Process according to Claim 9 in which the basic cations are selected from one or more of sodium, potassium, calcium, nitrogen and phosphorus, either alone or in appropriate cationic complex form.

11. Process according to any one of Claims 7 to 9 in which the catalyst includes alkali metal and acid cationic sites.

12. Process for production of diesel fuel, characterised in that lower olefins are converted into gasoline by the process of any one of Claims 7 to 9 the gasoline is converted by contact with a Friedel-Crafts catalyst into a hydrocarbon product having a significant fraction boiling in the distillate range.

13. Process for production of diesel fuel, which comprises converting a gasoline produced by the process of any one of Claims 7 to 9 by contact with a Friedel-Crafts catalyst to produce a hydrocarbon product a substantial portion of which boils in the distillate range with only a minor portion boiling in the gasoline range.

14. Process for production of diesel fuel which comprises the following steps:-(a) converting lower olefins at temperatures between about 100 to 450°C, pressures up to about 50 atmospheres, and LHSV of about 0.5 to 50hr-1, in contact with a zeolite catalyst which has been modified by substituting a significant portion of the cation sites thereof by basic cations, to produce a first hydrocarbon product containing hydrocarbons boiling in the gasoline boiling range;

(b) converting the said first hydrocarbon product by contact with a Friedel-Crafts catalyst into a second hydrocarbon product a substantial portion of which boils in the distillate range with only a minor portion boiling in the gasoline range.

15. Process for production of diesel fuel which comprises the following steps:-(a) converting lower olefins at temperatures between about 100 to 450°C, pressures up to about 50 atmospheres, and LHSV of about 0.5 to 50hr-1, in contact with a catalyst comprising a zeolite and a binder, said catalyst containing at least 0.2% of exchangeable basic cations, determined as oxides, on the total weight of the catalyst, to produce a first hydrocarbon product containing hydrocarbons boiling in the gasoline boiling range;

(b) converting the said first hydrocarbon product by contact with a Friedel-Crafts catalyst into a second hydrocarbon product a substantial portion of which boils in the distillate range with only a minor portion boiling in the gasoline range.

16. Process according to Claim 15, in which the first-mentioned catalyst contains at least 0.3% of exchangeable basic cations, determined as oxide, on the total weight of the catalyst.

17. Process according to Claim 15 or Claim 16 in which the binder comprises up to 90% by weight of the first-mentioned catalyst.

18. Process according to Claim 1, Claim 2 or Claim 3 in which the zeolite is of the ZSM family having an A1203 content of at least 1.0%.