NZ207108A - Conversion of lower olefins to higher-boiling hydrocarbons and production of diesel fuel - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £07108 -f, \~ 'xj ^ ^ ' 'v,,vN ~ "7/ t* iy/ i r l u [""priority Date(s): ... J J. 77, ^ — <P 2 Complete Specification Filed: Class: . £ f\7.C.

'••■•■••I '•••••• I Publication Date: 0 FEB 198.7 .

J v?. . , NEW ZEALAND PATENTS ACT, J 953 No.: Date: COMPLETE SPECIFICATION "PROCESS" X/Wc> THE BROKEN HILL PROPRIETARY COMPANY LIMITED, a company incorporated under the laws of the State of Victoria, Australia, of 140 William Street, Melbourne, Victoria, Australia; and COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION, a body corporate established under the Science and Industry Act 1949, of Limestone Avenue, Campbell, A.C.T. Australia, i" /■ hereby declare the invention for which >E / we pray that a patent may be granted to and the method by which it is to be performed, to be particularly described in and by the following statement: - 207108 - IOr Olefin conversion process The present invention is concerned with Vprocess ... for converting one or more lower olefins (as defined herein) into a mixture of hydrocarbons having boiling points in the gasoline boiling range. The product may be further conver-5 ted into a mixture of hydrocarbons of which at least some have boiling points in the distillate boiling range.

The oligomerisation of lower olefins using acid catalysts is well known - see, for example, Kirk-Othmer, "Encyclopaedia of Chemical Technology" 3rd Edition, 1978, 10 John Wiley, Vol. 4, p.362, which describes the preparation of a material useful as a gasoline blending stock. Higher severity oligomerisation to materials in the distillate range is possible, but the product, because of much skeletal isomerisation and branching, has a low cetane .5 number, for example, the tetra-isobutylene-olefin oligomer of isobutylene has a cetane no. of 15, compared with n-hexadecane (cetane) with a cetane no. of 100.

U.S. Patents 3,894,106 4,062,905 and 4,052,479 describe the conversion of alcohols and ethers to higher 10 hydrocarbons using a zeolite catalyst having a silica/ alumina ratio of at least 12 at a temperature of from 260 to 450°C. The preferred zeolite catalysts have crystal 3 densities which are not substantially less than 1.6 g/cm . These special catalysts are exemplified by ZSM-12 (as in ?108 West German Patent 2,213,109), ZSM-21, and certain modified naturally occurring zeolites. Synthetic zeolites made using an organic cation are preferred.

The aromatization of hydrocarbon feedstocks using zeolite catalysts is well known. Thus, U.S. Patent 3,760,024 describes an aromatization process for a feedstock comprising to paraffins and olefins which comprises contacting such a feedstock with crystalline aluminosilic- ates of the ZSM-5 family. U.S. Patent 3*756,942 describes contacting a feedstock having a boiling range of C_ to o o about 250 F (121.1 C) with a crystalline alurainosilicate zeolite of the ZSM-5 type and U.S. patent 4,150,062 describes an invention which involves the improved processing of lower olefins of from 2 to 4 carbon atoms to give a product comprising high octane gasoline components. The process comprises contacting the olefin feedstock in the presence of co-fed water with a catalyst comprising a zeolite having a silica/alumina molar ratio of at least 12. The crystalline aluminosilicate zeolites used in the catalyst composition of this process are generally referred to as the ZSM-5 family, or as behaving like ZSM-5, and include ZSM-5, ZSM-11, ZSM-12, ZSM-35, and ZSM-38.

Olefin oligomerisation using zeolites of the ZSM-5 family, such as ZSM-12, has also been disclosed in U.S. Patent 4,254,295- This describes a process for the selective oligomerization of linear and branched chain to olefins and comprises contacting the olefins, in the liquid phase, with a ZSM-12 zeolite at a temperature of from 80°F (26.7°C) to 400°F (204.4°C). It was found that the process provided selective conversion of the olefin feed to oligomer products with high selectivity, the product containing little or no light cracked products, such as paraffins, etc.

Lower olefins can be synthesised from alcohols, such as methanol, using zeolite catalysts similar to those try fc3s*fi 207108 described above, as disclosed, for example in U.S. 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 ether 5 derivatives, is completely converted at sub-atmospheric partial pressure to a mixture comprising mainly lower, olefins by contact with a particular type of crystalline ^ aluminosilicate catalyst.

Although it is generally accepted that zeolites 10 in the alkali metal form are of substantially reduced catalytic activity, in some cases completely inactive, the conversion of methanol using alkali metal modified zeolites has been described in U.S. Patent 3i&99,544. In the conversion of alcohols and ethers to higher hydrocarbons 15 using zeolite catalysts, if the zeolite is fully exchanged so that its cation content is substantially all alkali metal, most of its activity to catalyse the reaction is lost. Such high alkali metal content zeolites do, however, retain sufficient activity for some catalytic 20 roles, notably the dehydration of alcohols to 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 at the cationic site, or as in 25 the case of acid stable zeolites such as ZSM-5, by direct ^ exchange in acidic media), the catalyst is extremely v-*/ active for converting alcohols and/or ethers to higher hydrocarbons. For example, in the conversion of methanol to hydrocarbons by contact with an H-ZSM-5 zeolite catalyst 30 in which most of the alkali metal (usually sodium) has been exchanged, the hydrocarbon yield at 100% feed conversion is consistently about 44% by weight, based upon methanol fed; there is little conversion to dimethyl ether and other oxygenates. When none of the alkali metal has been 35 exchanged, the hydrocarbon yield is zero. •*31 1 ■1 "r: -.- ; v.;V 7 ^'-.v,./.,, . ...,,: 507108 - k - We have now developed an improved process for converting lower olefins (as defined herein) into a mixture of hydrocarbons having boiling points in the gasoline boiling range. The product may be further 5 converted into a mixture of hydrocarbons suitable for use as a diesel fuel.

Thus, it has been found that lower olefins, that is to Cg olefins and mixtures thereof, can be converted to higher hydrocarbons having boiling points in the gasoline lO boiling range, viz. to 196°C, using a modified zeolite catalyst and that the resulting hydrocarbons can be further converted to hydrocarbons of which at least some have boiling points in the distillate boiling range using a Friedel-Crafts catalyst.

According to the present invention, therefore, there is provided a process for converting one or more lower olefins (as defined herein) into a mixture of hydrocarbons having boiling points in the gasoline boiling range, in which the lower olefin(s) is/are contacted with a catalyst 20 comprising a zeolite in which some of the cationic sites are occupied by potassium, sodium, or calcium ions.

The invention also includes the further conversion of the gasoline mixture to a distillate mixture using a Friedel-Crafts catalyst.

The process of the invention for converting lower olefin(s) (as defined herein) to a gasoline mixture is preferably carried out at a temperature of from 100 to 450°C, more preferably from 300 to 450°C, at a pressure of up to 50 atmospheres (5066 kPa), and at a liquid space 30 velocity of from 0.5 "to 5-0/hour. The catalyst modification which leads to the improved process described herein involves the substitution of some of the cationic sites of the zeolite with potassium, sodium, or calcium ions, either alon.s|or in appropriate cationic complex form. 35 ,**£=£2=55!The zeolites used as catalysts are usually obtain- ;:-v ' ■ ' ed from a composition containing an organic cation.

After initially producing the zeolite crystal structure desired with its original organic and alkali metal cations, it is dried, and may then 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 either with other metal ions or with ammonium ions or both. Where acid sites are desired, ammonium cations are used. The ammonium form of the zeolite, upon calcination to remove ammonia, leaves the hydrogen form of the zeolite. The order of exchange and calcination is variable and several different sequences of operation reported to give special results for particular purposes are well known in the art.

A zeolite in accordance with the invention can be prepared by converting all of the cationic sites to the alkali metal form and then exchanging 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 of obtaining the zeolite of the 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 beneficial results, we observe that, after calcination, the composite catalyst performs as if a portion of the zeolite component had been replaced by alkali metal.

Another method of obtaining the zeolite of the invention is to calcine as-made zeolite, that is, zeolite containing both organic and alkali metal cations (with or without binder, as powder or pellet), so as to remove a portion of the organic cations. It will be appreciated that the relative amounts of organic and alkali-metal cations will depend on such variables as the nature ^ i - - .v:: - i "■■■■ N '~V I \ %Kir O' Q 207108 . i of the organic moiety, the relative concentrations of organic and alkali-metal in the synthesis gel, and, to some extent, the silica-alumina ratio of the zeolite, which can be adjusted by methods well known to those 5 skilled in the art. It will be appreciated that in this embodiment, the catalyst is not subjected to ion exchange after synthesis (see Examples 13, 20, 27 and 32 below).

In a preferred embodiment of the invention, the catalyst comprises a zeolite and a binder, the catalyst 10 containing at least 0.2% by weight, preferably at least 0.3%> of potassium, sodium or calcium ions, determined as oxide, based on the total weight of catalyst. The catalyst can comprise up to 90% by weight of binder, but preferably from 25 to 75%- Suitable binders include, for 15 example, bentonite and alumina.

The zeolite is preferably of the ZSM family and has an A1 0 content of at least 1.0% by weight. Whilst £ j the lower limits of alumina, and hence alkali metal, in the zeolite are determined by the need for sufficient 20 catalytic activity, the upper limits are determined by the maximum level of zeolitic alumina that can be accepted by a given zeolite. For example, it is well known that ZSM-5 typically has a maximum alumina content of about 4.5% by weight; in this case, the maximum alkali metal 25 content would correspond to about 80% of this value, cal-culated on a molar basis. Other zeolites can have much higher alumina contents, so that the corresponding maximum alkali content would be proportionally higher.

Those skilled in the art will realize that, on 30 the basis of the above, the catalyst (zeolite plus binder) of the present invention preferably has 20% of substituted ions on a molar basis relative to the alumina content of the zeolite. More preferably, the figure is 3®%- As indicated, it is a further aspect of the 35 present invention that a mixture of hydrocarbons obtained^p by the process described above can be further converted into a mixture of hydrocarbons of which at least some have boiling points in the distillate boiling range, the further conversion being carried out by contacting the first mixture of hydrocarbons with a Friedel-Crafts catalyst. Suitable catalysts for this further conversion are well known in the art and are described in "Friedel-Crafts and Related Reactions" , G.A. Olah (ed.) , Vols. 1 to 4, Interscience, 1963-1965.

Preferably, the second hydrocarbon mixture comprises, by weight, at least 40?S, more preferably at least 50% of hydrocarbons boiling at above 235°C» and preferably less than 50%, more preferably less than 40J6, of hydrocarbons boiling in the gasoline range. Such hydrocarbon mixtures are suitable for use as diesel fuels.

It has been indicated above that the zeolite of the invention has cationic sites occupied by potassium, sodium, or calcium ions. Other cationic sites in the zeolite may be occupied by ions incorporated in the catalyst for specific purposes, for example hydrogenation/ dehydrogenation components. For the purposes of this application, the sites occupied by these other components are considered to be acidic sites.

These additional components can be incorporated in the zeolite catalyst by impregnation, vapour deposition, or by exchange, according to preference.

It has been found that the catalysts of this invention are capable of converting alcohols such as methanol into an olefinic gasoline, but the catalyst deactivates quickly, for example, over a period of about five hours on line, making practical use of these catalysts for alcohol conversion difficult. Surprisingly, it has been found that olefin conversion over the catalysts of the invention continues to give useful yields of liquid product for much longer periods, for example, for more than thirty ■' .V ' \ 20710s hours on line, before reactivation (for example by-air calcination) is required.

In order that the invention may be more fully understood, the following examples are given by way of 5 illustration. Examples 1, 2, and 7 to 13, are concerned with the preparation of a catalyst in accordance with the invention, examples 3» 5, l4 to 20, and 28 to 33 describe processes according to the invention for converting a lower olefin into a mixture of hydrocarbons having boiling 10 points in the gasoline boiling range, and examples 4, 6, 21 to 27» and to 4l describe processes according to the invention for converting a mixture of hydrocarbons having ("*) boiling points in the gasoline boiling range into a mixture of hydrocarbons of which at least some have 15 boiling points in the distillate boiling range. Examples 42 and 43 are concerned with the conversion of methanol and dimethyl ether respectively using a catalyst in accordance with the invention.

Example 1 This example describes the synthesis of ZSM-5 with a high sodium content.

Aluminium wire (2.51g) was dissolved in sodium hydroxide solution (15.2g in lOOg water). The solution was then added to colloidal silica (667g of Ludox HS40 (trade mark)t 40% SiO ) and stirred. Tetrapropylammonium & bromide (l47-8g) in water (lOOOg) was then added and the whole vigorously stirred to a homogeneous gel. The gel was stiffened by the addition of sodium chloride (250g). The zeolite was crystallized from the mixture by heating 30 the gel in an autoclave to 175°C, with stirring, for 16 hours. The zeolite was obtained from the mother liquor by filtration and washing with distilled water. The as-made zeolite was then washed with 2M hydrochloric acid The 207108 < A1 expressed as Vt % Al^O^ and all Na expressed as Wt % Na20).

Example 2 This example describes a further synthesis of high sodium content ZSM-5- The zeolite was prepared in an analogous manner to .that described in Example 1 except that the weights of active components were: aluminium wire (l.28g) sodium hydroxide (7-5s) « colloidal silica (336.6g), tetra-n-propylammonivmi bromide (73-9g)• The same quantities of 2071.08 - 1 0 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 0.8% Na20.

Example 3 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 500°C. 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 300°C and the liquid products condensed (123g of liquid). The liquid was analysed by gas-15 chromatography (12.5m, SP2100, fused silica column) and a simulated 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 Product from Example 3.

Fraction Simulated Boiling Range Wt % gasoline <196°C 93.4 jet-fuel 196 - 235°C 4.3 middle distillate 1 235 - 317°C 1.7 middle distillate 2 >317°C 0.7 Example 4 This describes the conversion of the liquid product obtained in Example 3 into material boiling in 30 the distillate range. //a^. °\ *3S£p. f Pj9&6 ™ v-v- -7* ■> 1 S J 207108 - 11 - .

The liquid (30g) and anhydrous aluminium chloride (lOg) were refluxed (for 3 hours). The mixture was then hydrolysed by shaking 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 distillation profile are shown in Table 2 and clearly demonstrate the increase in boiling points obtained by AlCl^ treatment.

Table 2 Simulated Distillation Profile of Liquid Product from Example 4.

Fraction Simulated Boiling Range Wt % gasoline <196°C 28.6 jet-fuel 196 - 235°C 12.9 middle distillate 1 234 - 317°C 27.8 middle distillate 2 >317°C .6 Example 5 This describes the conversion of propylene over 20 acid ZSM-5 (H-ZSM-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. 350°C). The resulting liquid product (62g) was subjected to the same gas-chromatographic 3 0 analysis as described in Example 3. The results are 1. fs'fc-i'.'.'Wi".v V ' -■ "v-:v ' 207108 r.-,^.-''V.^'.'r - 12 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 Liguid Product from Example 5.

Fraction Simulated Boiling Range Wt % gasoline <19 6UC 91.6 jet-fuel 196 - 235°C -7 middle distillate 1 235 - 317°C 2.2 middle distillate 2 317°C 0.5 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 ifche relative ineffectiveness of the Friedel-Crafts treatment in Example 6 in that the major 20 portion of the product remains in the gasoline boiling-range.

Table 4 Simulated Distillation Profile of the Product obtained from Aluminium Chloride Treatment of Liquid 25 Product obtained from Example 5.

Fraction Simulated Boiling Range Wt % gasoline 19 6UC 76.9 jet-fuel 196 - 235°C -7 middle distillate 1 235 - 317°C 4.6 middle distillate 2 317°C 12.8 V fr .Qc ■ -.j' ^ • 'r '_'i;"kv ' - 207108 Examoles 7-13 These examples describe the characteristics of catalysts used in-following examples.

Table 5 Zeolite Analysis Catalyst Analysis (a) .

Example Code Si02/Al203 %Si02 %A12°3 WJa20 %FC203 (c) (d) 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 0.68 1.33 A4 40 78.5 8.0 1-31 1.19 11 A5 95 77.5 6.4 1.18 1.08 12 A6 95 82.0 7.0 1.28 1.21 13 A7 95 79.2 7.2 1.50 1.26 * (a) analyses, on a weight basis, of a 2/1, zeolite/bentonite 20 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 using tetra-n- propylammonium cation as organic templating cation. They 207108 were modified to differing sodium content as illustrated in Table 5. In examples 7 and 8 the catalysts were made from the "as-made" zeolites by ion-exchanging with' hydrochloric acid (2M) an<3 calcining the catalyst twice.

The sodium content of the zeolite before fabrication was very low. The zeolites were then mixed with bentonite (2/1, w/w) and formed into 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-propylammoniuin 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 content. Propylene, at 1 atm. pressure, was passed over a packed bed of the catalyst held at 300°C. 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. 207108 - u - - i.

Table 6 Example Catalyst WHSV (hr_1) Max Temp (°C), (a) Liquid Yield (b) I(A/0) (c) Zaliphatics (d) RON (clear) 14 Ex7 2.4 483 0.50 9.0 ' 41.3 100.0 Ex8 1.5 455 0.47 4.7 53.5 98.6 16 Ex9 2.2 445 0.49 0.5 79.5 95.5 17 ExlO 1.6 449 0.59 1.7 80.9 96.8 18 Exll 2.6 410 0.47 0.19 81.5 95.5 19 Exl2 2.8 433 0.34 0.20 83.3 92.3 Exl3 0.9 383 0.58 0.34 75.2 hot spot temperature. gg ^ of propylene converted.

Ratio of aromatic proton intensity/olefin proton intensity by ^"H N.M.R. from G.L.C.

Examples 14 and 15 illustrate that extensive exchange of the zeolite to remove alkali-cation results in higher aromatic content gasoline than if the zeolite is ion-exchanged and calcined just once (Examples 16-18). Example 19 illustrates that 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 quaternary cations (a) (b) (c) (d) 207108 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 5 These illustrate the conversion of the . gasolines described in Examples 14-20 into products boiling greater than 196°C.

Samples of gasolines 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 Example Product From HA/O) Product B.P. (simulated distillation) <196 °C 19 6-235 °C 235-317 °C >317 °C 21 Ex 14 6.8 69.4 .0 9-3 11.3 22 Ex 15 2.7 51.2 .0 16.3 22.5 23 Ex 16 0.4 49.1 8.4 .2 22.4 24 Ex 17 0.4 4 5 .1 17.0 22.4 .6 Ex 18 0.3 .6 12.2 29.6 32.6 26 Ex 19 0.4 33.6 8.7 .1 32.6 27 Ex 20 0.3 .3 II-1 27.0 31.6 207108 - 17-- Although all the gasoline feedstocks gave some products higher in boiling point than gasoline (<196°C), the products 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, the performance in the former case is preferred because more product in the middle distillate range (235-317°C) is obtained. These examples serve to illustrate that good yields of middle distillate and 10 higher products can be obtained from propylene by using catalysts of high exchangeable alkali-content, and that excessive removal of 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 containing 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) 2 5 is that one containing a zeolite with only one ion- exchange treatment and where the change in performance is less severe. Both catalysts produce high yields of aromatics at early time on line but for the preferred catalyst, this aromatic yield rapidly falls to a very low 30 value within 340 min. on-stream-time. 207108 - 18 - • Table 8 Example 28 Catalyst Ex-8, WHSV = l.lhr"1 Time Max Temp Liquid KA/O) %Aliphatics on- (°C) Yield > stream (gg ^ propene (min) converted) 190 455 0.41 17.6 33 309 449 0.51 6.1 46 509 (424) 0.57 1.8 49 751 433 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) KA/O) %Aliphatics on- (°C) Yield stream (gg propene (min) converted) 180 449 0.54 . 8.6 45.0 340 437 0.65 0.4 71.0 475 423 0.65 0.1 90.0 610 424 0.64 0.2 83.5 820 416 0.61 0.3 87.6 920 413 0.59 0.3 90.6 1105 398 0.49 0.01 89.4 1260 392 0.47 0.01 90.8 207108 Examples 30, 31 These illustrate the conversion of butylenes over the preferred catalyst as described in Example 9.

The results are given in Table 9. These results show that light olefins such as 1-butene and isobutene can be converted to olefinic gasolines over the alkali-metal containing catalysts.

Experiments using ethylene failed to give 10 significant yields of gasolines under similar conditions.

Table 9 Example 30 1-Butene Feed WHSV = lhr 1 Max Time On-Line Temp .

Liquid Yield KA/O) %Aliphatics (min) (°C) (gg"^" 1-butene converted) 180 3 66 .64 0.5 76.4 335 361 .76 0.2 74.6 470 359 .11 0.2 76.4 528 3 58 .13 0.1 79.1 718 354 .78 0.1 77.7 207108 < Example 31 Isobutene Feed WHSV = lhr"1 Time On Line (min) T°C (max) Liquid Yield (gg~^ isobutene converted) I(A/0) %Aliphatics 150 348 .64 0.4 70.9 . 290 344 .73 0.2 75.8 445 342 .73 0.1 78.6 595 340 .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 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 similar manner to 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/0) <0.1) with a RON (clear) of 96.1.

Example 33 This illustrates that alkaline earth cations of Group Ila beneficially produce an olefinic gasoline. iv#;'..;: - >- -1 -, 'y -;;T* . . r „ t v.'v'V 207 21 - A zeolite similar to those described in Examples 1 and 7 was treated with a calcium exchange solution.

After exchange and forming into an extrusion (2/1, zeolite/bentonite), the catalyst contained 3.50% CaO.

Propylene was passed over the catalyst in a similar manner to that described for Examples 14-20. The results are given in Table 10.

Table 10 O Example Exchange VHSV ' T T°C v ,j(a) Yield I(A/0) Cation (hr ) (max) 33 Ca 0.9 412 0.50 O.36 (a) g g -1 of propylene fed, average value.

The calcium treated zeolite (Example 33) gives an olefinic gasoline with acceptable yield.

Examples jk - 4l 25 These examples serve to illustrate that olefinic gasolines produced by the preferred catalysts can be converted, by a variety of catalysts, into a product containing significant quantities of kerosene, distillate and fuel-oil. The results are shown in Table 11, 30 where an olefinic gasoline feed was obtained from propylene using the catalyst described in Example 9.

.V'-v..-•■....••v.-- :v '-'a,: .vS v. * 207108 From 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 5 than gasoline. Hydrogen fluoride treated silica-alumina gave somewhat lower yields, as did the zeolite of Example 41.

These results illustrate that distillate 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.

Table 11 Catalyst Treatment Simulated Distillation Fuel Gasoline Kerosene Distillate Oil - Starting Gasoline Nil 91.6 3.4 3.6 1.4 Ex 34 aici3 Reflux 180 rains. 25 wt.% aici3 45.5 13.8 32.5 8.2 Ex 3 5 BF, on Silica- alumina 130°C overnight 25 wt.% catalyst 55.3 11.5 21.4 11.8 Ex 3 6 BF_ on S ilica-alumina 130°C overnight 12.5 wt.7, catalyst 62.6 11.5 17.1 8.9 Ex 37 AlCl^ on silica- alumina 130°C overnight 25 wt.% catalyst 68.6 .4 13.9 7.2 Ex 38 H^PO^ on kxeselguhr 130°C overnight 25 wt.% catalyst 80.0 .6 7.6 1.8 Ex .39 HF on silica- alumina 130°C overnight 25 wt.7. catalys t 84.8 7.4 . 6 2.3 2071Of Table 11 (continued) Catalyst Treatment Simulated Distillation - Fuel Gasoline Kerosene Distillate Oil Ex 4 0 bf3, hf on silica-alumina 130° C overnight 25 wt-% catalyst 87.1 6.1 4.6 .. 2-3 Ex 4 1 Example 7 130°C for 5 hoars 25 wt.% catalyst 87.3 .0 4.8 2.9 ■»*?) Ti ! >• BX 207108 -2 5- Example Jk-BT This example illustrates that methanol conversion over the preferred catalyst is unstable, and conversion can only be maintained for a limited on-5 stream-time.

A down flow reactor was charged with 70g of a catalyst formed as in Example 9. Methanol (at WHSV ~2.1hr "*") was passed over the catalyst at 360°C. A hot-, spot developed near the top of the bed, reaching 564°C. 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 43 This example illustrates the conversion of dimethylether (DME) over a high sodium catalyst.

Dimethylether (1000 ml min-"'') was passed over a 20 catalyst (70g) as described in Example 42. The details of the conversion are given in Table 12.

Claims (12)

-26- 207108 * Table 12 5 Time on line (min cumulative) Set Temp. (°c) Max Temp (°c) 7.DME in gas phase products (a) Hoc spot position 60 350 547 nil top of bed 300 350 572 1.8 bottom of bed 420 400 566 6.9 middle of bed 10 660 475 579 1.1 bottom of bed 750 475 557 54.4 bottom of bed (a) Liquid products condensed out at ambient temperature. 15 These results illustrate that the preferred catalysts, although capable of converting dimethylether, can only do so for a limited time on-line and that increasing the bed temperature fails to overcome the activity decay. This is in contrast to conversion of 20 light olefins, propylene, butylene etc., which are able to undergo conversion for much longer periods before regeneration is required. 27 207108 what we claim is". >

1. A process for converting one or more lower olefins (as defined herein) into a mixture of hydrocarbons having boiling points in the gasoline boiling range, in which the lower olefin(s) is/are contacted with a catalyst comprising a zeolite in which some of the cationic sites are occupied by potassium, sodium, or calcium ions.

2. A process according to claim 1, in which some of the cationic sites of the zeolite are acidic.

3- A process according to claim 1 or 2, in which the catalyst further comprises a binder and the zeolite contains at least 0.2.% by weight of potassium, sodium, or calcium ions based on the total weight of catalyst.

4. A process according to claim 3i in which the binder constitutes up to 90% by weight of the catalyst.

5. A process according to any of claims 1 to 4, in which the zeolite has an alumina content of at least 1.0% by weight.

6. A process according to any of claims 1 to 5i in which the zeolite is ZSM-5, ZSM-11, or ZSM-12.

7« A process according to any of claims 1 to 6, which is carried out at a temperature of from 100 to 450°C, at a pressure of up to 50 atmospheres (5066 kPa), and at a liquid space velocity of from 0.5 to 50/hour. 207108 - 28 -

A process for converting a mixture of hydrocarbons obtained by a process according to any of claims 1 to ( into a mixture of hydrocarbons of which at least some have boiling points in the distillate boiling range, in which the first mixture of hydrocarbons is contacted with a Friedel—Crafts catalyst.

9- A process for converting one or more lower olefins into a mixture of hydrocarbons having boiling points in the gasoline boiling range, substantially as herein described in Examples 3, 5, 14 to 20, and 28 to 33.

10. A process for converting a mixture of hydrocarbons having boiling points in the gasoline boiling range obtained by a process according to any one of claims 1 to 7 into a mixture of hydrocarbons of which at least some have boiling points in the distillate boiling range, substantially as herein described in Examples k, 6, .21 to 27» and 34 to 'il.

11. A process as claimed in any one of the preceding claims substantially as hereinbefore described with reference to any one of the examples.

12. Hydrocarbons boiling in the gasoline boiling range prepared by a process as claimed in any one of the preceding claims. DATED TH,3^ DAY '19^ A. J. PARK,Ji SON PER ' AGENTS FOR the APPLICANTS '