PRODUCTION OF HIGH-OCTANE GASOLINE BLENDING STOCK

Abstract: The process for preparing a high-octane gasoline involves catalyzing a light hydrocarbon containing one or more C₂-C₇ paraffins and/or C₂-C₇ olefins with a crystalline aluminogallo­ silicate with the skeleton comprised of SiO₄, AlO₄ and GaO₄ tetrahedra at temperatures ranging from 350°C to 650°C under a hydrogen partial pressure of not higher than 5 kg/cm². The crystalline aluminogallosilicate to be used as the catalyst for the process has its skeleton comprised of SiO₄, AlO₄ and GaO₄ tetrahedra and having the following formula: aM 2/n O·bAl₂O₃·Ga₂O₃·cSiO₂·dH₂O wherein M is a metal selected from an alkaline metal, and alka­ line earth metal and a mixture thereof, n is the valence of said metal, a is a positive number of (b+ 1) ± 3.0, b is between 0.3 and 30, c is between 8 and 2,000, and d is between 1 and 200.

Description: The present invention relates to a novel aluminogallosilicate catalyst and to the use of the catalyst for the preparation of high-octane gasolines from light hydrocarbons. Heretofore, the catalytic reforming of naphtha using a platinum aluminium catalyst has been extensively employed for the preparation of a high-octane gasoline. Naphtha to be used as a raw material is usually from fractions having boiling points in the range from 70°C to 180°C, when intended to be used for the preparation of gasoline for use in automobiles and from fractions having boiling points in the range from 60°C to 150°C, when intended to be used for the preparation of BTX. It is difficult to produce a high-octane gasoline from a light hydrocarbon containing paraffins and/or olefins having from 2 to 7 carbon atoms because the rate for the conversion to aromatic hydrocarbons may be decreased to remarkably low levels as the number of carbon atoms is decreased. At the present time, light hydrocarbons are used only in very limited ranges as raw materials in the field of petrochemistry and for the preparation of city gases. Therefore, a technology designed to be applied to produce high-octane gasolines from light hydrocarbons would be valuable. As techniques relating to the preparation of high-octane gasoline blending stock are known various processes which involve, for example, the catalysts with a crystalline silicate, particularly ZSM-5 silicate and those of the ZSM-5 type. Japanese Patent Early Publication No. 98,020/1984 discloses a process which comprises converting n-butane and propane to aromatic compounds by using a calcined product of a crystalline gallium silicate from a gel having the composition represented by the following formula: 3Na₂O: 9(C₃H₇)₄NOH: 0.33Ga₂O₃: 25SiO₂: 45OH₂O as a catalyst after the ammonium ion exchange and calcination. These conventional processes, however, are not yet satisfactory from the industrial point of view because the yield of the high-octane gasoline from light hydrocarbons is low. EP-A-0124271 discloses a crystalline galloaluminosilicate, useful in hydrocarbon conversion processes, whose composition in terms of mole ratios of oxides is as follows: 0.9 ± 0.2M 2/n O · Al₂O₃ · aGa₂O₃ · bSio₂ · zH₂O wherein M is a cation, suitable H⁺, NH₄⁺, a metallic cation or an organic nitrogen cation; n is the valence of the cation, a has a value between 0.0001 and 2; b has a value of at least 12; and z has a value of from 0 to 40. The present invention provides a crystalline aluminosilicate catalyst which is especially suitable for the preparation of a high-octane gasoline from light hydrocarbons. More particularly, the present invention provides a crystalline aluminogallosilicate catalyst having a skeleton comprised of SiO₄, AlO₄ and GaO₄ tetrahedra and being represented in terms of molar ratios of the oxides calcined at 500°C or higher by the formula: a M 2/n O · bAl₂O₃ · Ga₂O₃ · cSiO₂ · dH₂O wherein: M is at least one metal, n is the valence of said metal, a is a positive number of (b + 1) ± 3.0, b is from 1.17 to 6.09 inclusive, c is from 83.1 to 437.5 inclusive, d is from 1 to 200 inclusive, and the ratio c/b + 1 is from 38.295 to 61.707 inclusive, or a catalyst as defined above but wherein at least a portion of said metal M is replaced by hydrogen; and the catalyst having been treated with hydrogen gas in order to prolong the maintenance of its aromatization activity for the preparation of a high-octane gasoline from a light hydrocarbon containing one or more paraffins and/or olefins each having 2 to 7 carbon atoms. Further, the present invention provides a process for the preparation of a high-octane gasoline, which comprises contacting a light hydrocarbon containing one or more paraffins and/or olefins, each having 2 to 7 carbon atoms, with a catalyst as defined in the preceding paragraph. The present invention will now be described more in detail and with reference to the drawings appended hereto, in which: Fig. 1 is a graph showing the relationships of reaction temperatures versus conversion and aromatics yields of an aluminogallosilicate according to the present invention and the comparing aluminosilicate and gallosilicate; Fig. 2 is a graph showing the relationships of times versus conversion and aromatics yields of an H₂-treated aluminogallosilicate according to the present invention compared with the same catalyst which has not been H₂-treated; and Fig. 3 is a graph showing the relationships of regeneration cycles versus conversion, aromatics yields and hydrogen yields of an aluminogallosilicate meeting the composition requirement of the present invention during the repetition of the reaction and regeneration cycles. The terms "high-octane gasoline blending stock" and related ones used in the present specification refer to hydrocarbons having an octane number of 95 or higher, when determined by the research method, and containing a large quantity of aromatic hydrocarbons with carbon atoms in the range from 6 to 10. The high-octane gasoline may be used as automobile fuel and for the preparation of aromatic hydrocarbons. The term "light hydrocarbons" referred to herein as raw materials for the preparation of high-octane gasoline means hydrocarbons containing a paraffin and/or an olefin with carbon atoms ranging from 2 to 7 as a major constituent. Representative of light hydrocarbons are light fractions having boiling points of 100°C or lower obtainable from naphtha fractions containing a paraffin of carbon atoms ranging from 5 to 7 as a major constituent. The crystalline aluminogallosilicate according to the present invention may be produced by the gel crystallization method using hydrothermal synthesis or by the method of inserting gallium into the lattice skeleton of an aluminosilicate or a zeolite crystal, to prepare in the first instance a catalyst of the formula given above where M is present and is selected from an alkaline metal, an alkaline earth metal and a mixture thereof. The gel crystallization method is simpler because an objective quantity of aluminium and gallium can be contained at the same time in the preparation of the crystalline aluminogallosilicate. A crystalline aluminogallosilicate may be produced by this method by causing an aqueous mixture containing an alumina source and a gallia source as an essential constituent, in addition to a constituent necessary for the silicate synthesis, to be retained under conditions for the hydrothermal synthesis. As sources of silica may be used, for example, a silicate such as sodium silicate or potassium silicate, colloidal silica, silica powder, dissolved silica and soluble glass. As sources of alumina are used, for example, an aluminium salt such as aluminium sulfate or aluminium nitrate, an aluminate such as sodium aluminate, and alumina gel. As sources of gallia are used, for example, a gallium salt such as gallium nitrate or gallium chloride, and gallium oxide. As a further source of alumina or gallia, there may be used a solution or a hydroxide containing aluminium or gallium obtainable during the extraction or purification step of a deposit such as a bauxite deposit, zinc deposit or the like. An organic additive may also be used in order to accelerate the growth of a desired crystalline aluminogallosilicate and improve the purity thereof, thus yielding products of better quality. As organic additives useful in this method are, for example, quaternary ammonium salts such as a tetrapropylammonium salt, a tetrabutylammonium salt or a tripropylmethylammonium salt, an amine such as propylamine, butylamine, aniline, dipropylamine, dibutylamine or morpholine, an aminoalcohol such as ethanolamine, diglycolamine or diethanolamine, an alcohol such as ethanol, propylalcohol, ethylene glycol or pinacol, an organic acid, an ether, a ketone, an amino acid, an ester, a thioalcohol and a thioether. A compound that produces such organic additives under the hydrothermal synthesis conditions may also be employed. As a source of an alkali metal or an alkaline earth metal, there may be used, for example, a hydroxide, a halide, a sulfate, a nitrate or a carbonate of an alkali metal such as sodium or potassium or an alkaline earth metal such as magnesium or calcium. The raw material may contain a mineral acid such as sulfuric acid or nitric acid as a pH adjusting agent, in addition to the above-described compounds. An aqueous mixture containing one or more of the above-described compounds to be used as a raw material may be subjected to crystallization at temperatures of from 50°C to 300°C, preferably from 100°C to 250°C under autogenous pressures for a retention period of from about 1 hour to 7 days, preferably from 1 to 5 days. The product obtained by the above-mentioned process is subjected to treatment with hydrogen to help maintain its aromatization activity and may be subjected to further modification treatment as needed. Accordingly, the crystalline aluminogallosilicate referred to herein may also include a variety of modified products obtainable by the modification treatment in addition to those producible by the hydrothermal synthesis and hydrogen pretreatment. An MASNMR (Magic Angle Spinning Nuclear Magnetic Resonance) analysis may give useful information on the elements present in the crystal structure of the crystalline aluminogallosilicate and on the composition thereof. For example, the ²⁷Al-NMR analysis of an aluminosilicate gives information on the tetrahedral configuration in the anionic skeletal structure. The ²⁹Si-NMR analysis gives information on the four tetrahedra (TO₄; T = Al, Si, Ga, etc) adjacent to the (SiO₄) tetrahedron in the structure thereof. In the aluminogallosilicate described hereinabove, the ²⁷Ga-NMR analyses show that the Al and Ga elements of the tetrahedral configuration are present in the skeletal structure. From information provided by the ²⁹Si-NMR analysis, the mole ratio of SiO₂ to (Al₂O₃ + Ga₂O₃) in the crystal structure is computed. One of the chemical characteristics of the crystalline aluminogallosilicate is its acid property. Generally, the degree of acidity may be determined by means of the temperature programmed desorption or the measurement for heat of adsorption using a basic substance such as ammonia or pyridine. As the degrees of acidity balancing the aluminium and gallium used for synthesis are measured in the aluminogallosilicates, it is apparent that the aluminium and gallium are present in the anionic skeletal structure of the crystal structure and strong acid sites develop. In a preferred aspect, the crystalline aluminogallosilicate according to the present invention is characterized in that aluminium is present in an amount ranging from 0.1% to 5.0% by weight and gallium in an amount ranging from 0.1% to 10.0% by weight in the skeletal structure, and the value of d in the formula for the catalyst is from 1 to 50. Most preferable silicates are of the MFI type and/or of the MEL type. The MFI type and MEL type silicates belong to the structural type of the known zeolites of the kind published in "The Structure Commission of the International Zeolite Association" (Atlas of Zeolite Structure Types; W.M. Meiyer and D.H. Olson (1978), distributed by Polycrystal Book Service, Pittsburgh, PA, USA). The aluminogallosilicates obtainable by the hydrothermal synthesis as described above contain an alkali metal such as sodium or potassium and/or alkaline earth metal such as magnesium or calcium, and they may be subjected to various conventional modification treatment as desired. For example, they may be converted to the ammonium form by the ion exchange in an aqueous solution containing an ammonium salt such as ammonium chloride, ammonium nitrate or the like and then subjected to ion exchange in an aqueous solution containing ions of a metal other than the alkali metal and the alkaline earth metal, thus introducing thereinto a desired metal other than the alkali metal and the alkaline earth metal. The aluminogallosilicate in the ammonium form may be converted to the hydrogen form by calcination at temperatures ranging from 350°C to 650°C. The modification treatment referred to herein may also include a treatment that removes at least a portion of an alkali metal and/or an alkaline earth metal contained in the synthesized aluminogallosilicate, and such modification treatments are well known to those skilled in the art because they are conventional with respect to conventional crystalline zeolites. The crystalline aluminogallosilicates according to the present invention may be utilized in various forms, and for instance they may be formulated as a powder, or as a molded product such as a granule, a sheet or a pellet by means of extrusion molding, spray drying, or tableting press molding after an addition of a binder such as alumina or silica. The above-described modification treatments may also be applied to such molded products as well as to powdery products. Further, desired metal may be introduced into the molded products by ion exchange or by impregnation so as to be carried by the aluminogallosilicate. Metals capable of being introduced may include, for example, magnesium, calcium, strontium, barium, manganese, rhenium, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, zinc, aluminium, indium, germanium, tin, lead, phosphorus, antimony, bismuth, selenium or the like. The crystalline aluminogallosilicates according to the present invention exhibit extremely superior catalytic activities as catalysts for the preparation of high-octane gasoline using light hydrocarbons as raw materials, and their catalytic activities are higher than those of conventional aluminosilicates and gallosilicates. In order to produce the high-octane gasoline using aluminogallosilicates in accordance with the present invention, light hydrocarbons are catalyzed with the crystalline aluminogallosilicate according to the present invention, preferably at temperatures ranging from 350°C to 650°C under hydrogen partial pressures of 5 kg/cm² or lower. In this case, the use of the crystalline aluminogallosilicates in the hydrogen form is preferred, and the aluminogallosilicates in the hydrogen form preferably carry a metal constituent as an additional constituent to improve the catalytic activity. Suitable metals include, in addition to those mentioned above, lanthanum, cerium, titanium, vanadium, chromium, molybdenum, tungsten and lead. Such additional metals may be used singly or in combination of two or more, and the carried quantity may be in the range from 0.1 to 10% by weight when reduced to a metal basis. As a method of causing a metal to be carried by the catalyst may be used conventional techniques such as the ion exchange method, impregnation method and so on. The aluminogallosilicates catalysts in accordance with the present invention may also carry one or more metals selected from magnesium, calcium, lanthanum, cerium, ruthenium and iridium in order to prevent coke from being accumulated. In this case, the carrier amount may be in the range from 0.01% to 5% by weight when reduced on a metal basis. Reaction temperatures to be applied to the conversion reaction of the light hydrocarbons according to the present invention may be determined depending upon the composition of the light hydrocarbon serving as the raw material, the desired yield of the high-octane gasoline and so on, but they range preferably from 350°C to 650°C. If the reaction temperatures are lower than 350°C, the production of byproducts such as light gases, e.g. methane, ethane or the like, can be prevented, but the yields of the high-octane gasoline are decreased. If the reaction temperatures are higher than 650°C, the yields of the high-octane gasoline can be increased but the catalytic deactivation may be accelerated by means of coke or the like, thereby reducing the life of the catalyst. The reaction temperatures may range more preferably from 450°C to 650°C for the light hydrocarbons containing a n-paraffin as a major constituent, from 400°C to 600°C for the light hydrocarbons containing an isoparaffin as a major constituent, and from 350°C to 550°C for the light hydrocarbons containing an olefin as a major constituent. In the conversion processes described above, high pressures are not particularly required because a sufficient yield of the high-octane gasoline can be attained under ambient pressures. However, if the reactants contain a large quantity of light gases such as ethane or propane or in instances where a byproduct, hydrogen, or propane or butane is used as an LPG, it is economically advantageous to use elevated pressures as high as about 20 kg/cm². As reactions including the dehydrogenation proceed in the conversion of the light hydrocarbons to the high-octane gasoline, the hydrogen partial pressures balancing the reaction can be attained under reaction conditions without an addition of hydrogen. An intentional addition of hydrogen may have the advantages that the coke accumulation can be prevented and the catalyst life can be prolonged, but it is not necessarily advantageous because an increase of the hydrogen partial pressure may radically decrease the yields of the high-octane gasoline. It is accordingly preferred to restrict the hydrogen partial pressures to 5 kg/cm² or lower. The reaction process for the conversion of light hydrocarbons to high-octane gasoline may be carried out using a fixed bed, moving bed or fluidized bed of the catalyst. The quantity of the reactants to be used for the fixed bed mode may range from 100 to 10,000 hr _1 , preferably from 100 to 2,000 hr _1 as a gas space velocity. If a reaction mode other than a fixed bed is used, the catalytic period may be determined so as to be equivalent to that of the fixed bed. The crystalline aluminogallosilicates according to the present invention are superior in catalytic activities with respect to the conversion reaction of the light hydrocarbons to the high-octane gasoline to conventional aluminosilicates and gallosilicates. Furthermore, the crystalline aluminogallosilicates according to the present invention are advantageous in terms of manufacturing costs because of the low content of gallia as compared to conventional gallosilicates. Moreover, they have properties as a solid acid superior to aluminosilicates and gallosilicates. The present invention will be described more in detail by way of working examples. Example 1: Preparation of Aluminogallosilicates (Prior to Hydrogen Pretreatment) A total number of 17 crystalline aluminogallosilicates were prepared in accordance with the following procedures. A solution (I) was prepared from sodium silicate (J Sodium silicate # 3: 28-30% by weight of SiO₂; 9-10% by weight of Na₂O; balance, water; Product of Nippon Kagaku Kogyo K.K.) in the amount shown under the column q-1 in Table 1 below and water in the amount shown under the column q-2 therein. Another solution (II) was prepared from Al₂(SO₄)₃ · 14 ∼ 18H₂O in the amount shown under the column q-3 in Table 1 below, Ga(NO₃)₃ · 9H₂O in the amount shown under the column q-4 therein, tetrapropylammonium bromide in the amount shown under the column q-5 therein, H₂SO₄ (97% by weight) in the amount shown under the column q-6 therein, NaCl in the amount shown under the column q-7 therein and water in the amount shown under the column q-8 therein. The solution (II) was gradually poured into the solution (I) with stirring at room temperature, and the mixture was stirred with a mixer for 5 minutes. After the stirring, the mixture was placed in a stainless steel autoclave and subjected to crystallization at 180°C under autogenous pressure. The resultant gel was then charged to the autoclave that in turn was sealed and heated to 180°C. The gel was held for 5 days therein, and the crystalline product was separated from its mother liquor by filtration, washed five times with a 1-liter portion of water and then dried at 120°C for 3 hours. The dried product was then calcined at 550°C for 3 hours in air. After the calcined product was taken, it was filtered by suction and then washed five times with a 1-liter portion of water. The filtered solid material was dried at 120°C for 3 hours and then calcined at 55°C for 3 hours under air streams to produce each of the 17 aluminogallosilicates. The products were determined to be of the MFI structure type by X-ray diffraction. Table 1 below indicates the components of aqueous mixtures that are raw materials for aluminogallosilicates Al/Ga-l to Al/Ga-17, respectively. The mole ratios of the aluminogallosilicate may be represented by the following formula: CSiO₂: bAl₂O₃: Ga₂O₃: yH₂O: zH₂O The compositions of the aluminogallosilicate are shown in Table 2 below. Example 2: Preparation Of Catalysts in H-Form Each of the aluminogallosilicates Al/Ga-1 to Al/Ga-17 obtained in Example 1 was blended with alumina powder (Cataloid AP; Catalyst & Chemicals Ind. Co., Ltd.) and additional water. The mixture was blended in proportions to give about 73% aluminogallosilicate and about 27% Al₂O₄ in the final product. The blended mixture was then extruded through about 1/32" opening die plate. The extrudate was dried at 120°C for 3 hours in air and then calcined at 550°C or 3 hours under air streams. Afte cooling, the extrudate was ion-exchanged four times at 100°C, each for two hours with a 2.2N ammonium nitrate aqueous solution at the rate of 5 ml per 100 grams of the calcined extrudate. The resultant NH₄⁺- form extrudate was washed, dried at about 120°C for 3 hours in air and then calcined at about 550°C in air to give the H-form aluminogallosilicate catalyst No. I to XVII in the H-form as shown in Table 2 above. Catalyst Nos: VII and IX-XI have compositions in accordance with this invention, but are not yet hydrogen pretreated as required by the invention. The other catalysts are included for comparative purposes. The additional comparative purposes, using the seven crystalline aluminosilicates (Al-1 to Al-7) and the nine crystalline gallosilicates (Ga-1 to Ga-9), each having the mole ratios indicated in Table 3 below, the H-form aluminosilicates (H-[A1l-1] to H-[Al-7]) and the H-form gallosilicates (H-[Ga-1] to H-[Ga-9]) were prepared in substantially the same manner as above. These aluminosilicates and gallosilicates were identified to be of the MFI structures type by X-ray diffraction analysis. Examples 3 to 19 and Comparative Examples 1 to 18: Conversion of n-Hexane Using the H-fonn aluminogallosilicate catalysts Nos. I to XVII, the conversion reaction of n-hexane was conducted using a flow reactor under the following reaction conditions: temperature, 538°C; pressure, 1 atm.; hydrogen partial pressure, 0.5 kg/cm² or lower; LHSV, 2 hr _1 ; catalyst amount, 3 ml (sieved to pass 16 to 24 mil); reaction time, 1 hour. The resultant products were analyzed by a gas chromatograph connected to the reactor. For additional comparative purposes, the above procedures were followed with the exception that the H-form aluminosilicates Nos. H-[Al-1] to H-[Al-7] and the H-form gallosilicate Nos. H-[Ga-1] to H-[Ga-9] indicated in Table 5 above were used as catalysts. Furthermore, an equimolar mixture of the aluminosilicate H-[Al-1] with the gallosilicate H-[Ga-3] was treated in virtually the same manner as in Example 2 to give the H-form aluminosilicate/gallosilicate H-([Al-1] + [Ga-3]). The above test was conducted using this as a catalyst. Tables 5 and 7 shown compiled reaction data with respect to the aluminogallosilicates. Tables 6 and 7 show compiled reaction data with respect to the aluminosilicates and the gallosilicates used for comparative purposes. From data from the catalysts obtained in Example 12 and Comparative Example 17, it is indicated that the aluminogallosilicate according to the present invention is different from a physical mixture of the aluminosilicate with the gallosilicate. Example 20 Using the H-form aluminogallosilicate No. X prepared in Example 2, as shown in Table 2, the reaction was carried out using light naphtha having the composition as shown in Table 4 below, under the reaction conditions: temperature, 538°C; pressure, 3 kg/cm²G; hydrogen partial pressure, 1 kg/cm² or lower; LHSV, 1 hr _1 gas present, N₂ (flow rate: 10N liter/hour);catalyst amount, 20 cc. Table 7 below shows compiled data of the reactions carried out above. The data for Example 20 were obtained in 19 hours after the start of the reaction. In the Table, references to hydrocarbons mean the following: Example 21: Preparation of Aluminogallosilicates of the MEL Structure Type And Their Catalysts A solution (I) was prepared from 464.5 g of sodium silicate (J Sodium silicate # 3; SO₂: 28-30% by weight; Na₂O: 9-10% by weight; balance, water; Nippon Kagaku Kogyo K. K.) and 520 g of water. A solution (II) was prepared from 17.0 g of Al₂(SO₄)3 · 14-18H₂O, 8.7 g of Ga(NO₃)₃ · 9H₂O, 143.4 g of tetrabutylammonium bromide, 43.3 g of H₂SO₄ (97% by weight) and 550 g of water. The solution (II) was poured gradually into the solution (I) at room temperature, and the mixture was allowed to stand overnight in a sealed container and then stirred for 5 minutes with a mixer. After stirring, the mixture was placed in a stainless steel autoclave and subjected to crystallization at 102°C for 5 days and then at 180°C for 1 day under autogenous pressure. The product was then filtered by suction, and it was washed with water and filtered. This procedure was repeated five times. The resultant solid substance was dried at 120°C for 3 hours and then calcined at 550°C for 3 hours under air streams to give an aluminogallosilicate. The product was identified to be the MEL structure type by X-ray diffraction. The mole ratios of the aluminogallosilicate were as follows: 162.9SiO₂: 2.58Al₂O₃: Ga₂O₃: 3.03Na₂O: 16.2H₂O Thus, the ratio C/b + 1 in this catalyst is 45.5 within the range required for this invention. Preparation of Catalysts: The resultant aluminogallosilicate was then blended with alumina powder (Cataloid AP: Catalyst & Chemicals Ind. Co., Ltd.) and additional water. The aluminogallosilicate and the Al₂O₃ were then blended in proportions to give ca. 73% aluminogallosilicate and ca. 27% Al₂O₃ in the final product. The mixture was then extruded through an about 1/32" opening die plate. The extrudate was dried at about 120°C for 3 hours in air and then calcined at about. 550°C for 3 hours in air. After cooling, the extrudate was subjected to ion exchange four times, each for 2 hours with 5 ml of a 2.2N ammonium nitrate solution at 100°C per gram of the calcined extrudate. The resultant NH₄-form extrudate was then washed, dried at about 120°C in air and again calcined at about 550°C for 3 hours in air to give a H-form aluminogallosilicate. Example 22: Conversion of n-Hexane Using the H-form aluminogallosilicate obtained in Example 21 as a catalyst, the conversion reaction of n-hexane was carried out in the same manner as in Example 3. The reaction results were 100% for a conversion rate and 71.5 C% by weight for an a romatics yield. Example 23: The aluminogallosilicate Al/Ga-9 as shown in Table 2 was blended with silica sol (Cataloid SI-35O: SiO₂, 30% by weight; Catalyst & Chemicals Ind. Co., Ltd.) and additional water. The aluminogallosilicate and the SiO₂ were blended in proportions to give ca. 73% aluminogallosilicate and ca. 27% SiO₂ in the final product. The mixture was then dried and calcined as previously described. The calcined product was broken and sieved to pass 16 to 24 mesh. The H-form aluminogallosilicate catalyst was prepared as described in Example 2. Using the H-form aluminogallosilicate above as a catalyst, the conversion reaction was carried out in substantially the same manner as described in Example 3. The results were 100% for a conversion rate and 66.3C% by weight. Example 24: Dependency on Reaction Temperatures Fig. 1 shows the relationships of the aromatics yields (curved line 12) and the conversion rates of n-hexane (curved line 15) vs. reaction temperature for the aluminogallosilicate catalyst IX as shown in Table 2 with the aromatics yields (curved lines 13 and 14, respectively) and the conversion rates (curved lines 16 and 17, respectively) for the aluminosilicate catalyst H-[Al-4] as shown in Table 3 and the gallosilicate catalyst H-[Ga-3] as shown in Table 3. Reaction conditions and procedures were the same as described in Example 3 except temperatures. It was found that the aluminogallosilicate was higher in an aromatization activity than the gallosilicate which in turn was higher than the aluminosilicate over the whole temperature areas tested and consequently that the aluminogallosilicate catalyst having a composition as required according to the present invention was superior to the others. The Examples given so far demonstrate the advantages of crystalline aluminogallosilicate catalyst whose compositions meet the requirements of this invention even before the catalysts have been subjected to a hydrogen treatment. The next two Examples illustrate additional advantages of such a pretreatment. Example 25: Effects of H₂ Treatment In order to confirm the effects of the pre-treatment with hydrogen on the conversion of n-hexane, the aluminogallosilicate was subjected to pre-treatment with hydrogen under conditions: temperature, 600°C; pressure, 1 atm.; treatment time, 2 hours; and hydrogen flow rate, 100 cc/minute. The conversion reaction of n-hexane was carried using the aluminogallosilicate IX as shown in Table 2 under the following conditions: temperature, 538°C; pressure, 1 atm.; LHSV, 2 hr _1 ; and reaction time, 25 hours. Table 9 below and Fig. 2 indicate the reaction results. As shown in Fig. 2, it was confirmed that the hydrogen treatment gave the effect on the maintenance of the aromatization activity for the aluminogallosilicate catalysts. The effect of the hydrogen treatment on the stability of the gallium and aluminium incorporated into the crystal skeleton will be indicated in Example 26. Example 26: Stability of Catalysts In order to confirm the stability of the aluminium and the gallium in the crystal skeleton of the aluminogallosilicate, the test was conducted in comparison with an aluminosilicate carried with gallium under the reaction conditions as will be shown in Table 10 below. The experiment was carried out using a reactor filled with the catalyst. After the treatment under the above conditions, the specimens were subjected the X-ray fluorescence analysis to measure degrees of the desorption of the aluminium and gallium. Table 11 below shows the test As will be shown in the table, it was confirmed that no desorption of the aluminium and gallium in the crystal skeleton of the aluminogallosilicate was recognized. Example 27: Reaction/Regeneration Cycle Test Tests for the regeneration of the catalyst were carried out by repeating the burning of coke on the aluminogallosilicate catalyst in dilute air after the the reaction. The reaction and regeneration conditions are shown respectively in tables 12 and 13. Fig. 3 shows the compiled test results. It was found that the aromatization activity was maintained to virtually constant levels as the conversion rates were almost 100% as shown by the curved line 22, the aromatics yields were about 64 C% by weight as shown by the curved line 23, and the hydrogen yields were about 4.5% by weight as shown by the curved line 24. Example 28: Measurement of Acidity Using the aluminosilicate (mole ratio of SiO₂/Al₂O₃: 66) Al-4 and the gallosilicate Ga-3, prepared for comparative examples, and the aluminogallosilicate Al/Ga-10 as shown in Example 1 as samples, the ion exchange treatment was conducted using anmmonium nitrate, thereby replacing a majority of the alkali metals contained in the samples. The samples were then dried and calcined at 550°C. The thus calcined samples (each about 0. 1 g) were heated at 400°C for 3 hours under vacuo for deaeration. A degree of vacuum at this moment in each case was found to be 1 × 10 _4 torr or lower. Using a multi-purpose calorimeter (manufactured by Tokyo Riko K. K.), each of the calcined samples was measured for heat of adsorption that generated when ammonia was added at the rate as small as 0.163 ± 0.027 cc per gram of the sample at 25°C in the standard state at many times for adsorption. The measured results are shown in Table 14 below. As is apparent from the table above, the aluminogallosilicate having a composition according to the present invention is large with respect to the quantity of adsorption that generates the heat of adsorption equal to those of the aluminosilicate and the gallosilicate. As the degree of acidity balancing the aluminum and gallium used for the synthesis was found in the crystalline aluminogallosilicates according to the present invention, it is implied that the aluminium and gallium are present in the crystal structure. Example 29: ²⁹SI-MASNMR Measurement The ²⁹Si-MASNMR measurement was carried out using Model JNM-GX270 FTNMR (manufactured by Nippon Denshi K. K.) equipped with a solid CP/MAS unit (NM-GSH27HU). The measurement was conducted using the gated decoupling method under the following conditions: observed frequency, 53.67 MHz; data point, 8192; observed spectral width, 20,000 Hz; number of integration, 3,000-4,000; angle of pulse, 45′ (5.3 µs); pulse repetition time, 5 seconds; and exterior standard substance, tetramethylsilane. Each of the measured ²⁹Si-MASNMR spectra was subjected to waveform dissociation treatment and divided in to Gauss type components. It was measured from the ²⁹Si-MASNMR spectra that, among the four tetrahedra (TO₄; T = Al, Ga or Si) adjacent to the (SiO₄) tetrahedron in the structure, both the tetrahedron in which T is occupied all by Si (represented by Si(OM)) and the tetrahedron in which only one of T's is occupied by Al or Ga (represented by Si(lM)) were present. The mole ratios of SiO₂ to (Al₂O₃ + Ga₂O₃) were computed from the ratios of the spectral areas of Si(OM) to those of Si(lM). Table 15 below shows the results. It is shown in Table 15 that the mole ratio of SiO₂ to (Ga₂O₃ + Al₂O₃) determined by the elemental analysis is virtually equal to that of the MASNMR and consequently that the aluminium and gallium are present in the crystal structure. Example 30: Preparation of Catalysts Carried With Metals The extrudate (10 grams) of the NH₄-form aluminogallosilicate IX as shown in Table 2 was treated by getting it into contact with an aqueous solution of a metal salt in a manner as will be described below. The extrudate was dired at 120°C for 3 hours in air and then calcined at 550°C for 3 hours under air streams, thereby leading to the production of a final catalyst composition carried with the metal in the amount (as an elemental metal) as will be described below. Na: The extrudate was immersed in a solution of 0.05 g of sodium nitrate in 11.6 ml of deionized water for one day at room temperature, filtered and washed with water. The amount of the metal carried was 0. 12% by weight. Mg: The same procedures as above were followed except that the immersion was conducted in a solution of 0.81 g of Mg(NO₃)₂ · 6H₂O in 10 ml of deionized water. The metal amount was 0.30% by weight. La: The same procedures as above were followed except that the extrudate was immersed in a solution of 0.91 g of La(NO₃)₃ · 6H₂O in 10 ml of deionized water. The metal amount was 1.20% by weight. V: The extrudate was immersed in a solution of 0.64 g of NH₄VO₃ in 40 ml of deionized water at 65°C for 2 hours, filtered and washed with water. The metal amount was 0.90% by weight. Cr: The extrudate was immersed in a solution of 4 g of Cr(NO₃)₃ · 9H₂O in 50 ml of deionized water at room temperature for 7 days, filtered and washed with water. The metal amount was 0.45% by weight. W: The extrudate was immersed in a solution of 1.13 g of (NH₄)₁₀W₁₂O₄₁ · , 5H₂O in 60 ml of deionized water at 60°C for one day, filtered and washed with water. The metal amount was 3.05% by weight. Mn: The same procedures as with Na were followed except for the immersion in a solution of 0.18 g of Mn(NO₃)₂ · 6H₂O in 6.58 ml of deionized water. The metal amount was 0.36% by weight. Re: The same procedures as with Na were followed except for the immersion in a solution of 0. 17 g of NH₄ReO₄ in 6.58 ml of deionized water. The The metal amount was 0.31% by weight. Ir: The same procedures as with Na were followed except for the immersion in a solution of 0.21 g of IrCl₃ ·1.5H₂O in 15 ml of deionized water for 2 days. The metal amount was 0.53% by weight. Ni: The same procedures as with Na were followed except for the immersion in a solution of 7.27 g of Ni(NO₃)₂· 6H₂O in 50 ml of deionized water at 100°C for 4 hours. The metal amount was 0.28% by weight. Pt: The same procedures as with Na were followed except for the immersion in a solution of 0.08 g of Pt(NH₃)₄Cl₂ in 6.58 ml of deionized water. The metal amount was 0.42% by weight. Zn: The same procedures as with Na were followed except for the immersion in a solution of 0.74 g of Zn(NO₃)₂ in 50 ml of deionized water for 4 hours. The metal amount was 0.35% by weight. Sn: The same procedures as with Na were followed except for the immersion in a solution of 0. 17 g of SnC₂O₄ in 10 ml of deionized water and 2 g of HCl. The metal amount was 0.74% by weight. P: The same procedures as with Na were followed except for the immersion in a solution of 0. 17 g of NH₄HPO₄ in 10 ml of deionized water for 7 days. The metal amount was 0. 34% by weight. Sb: The same procedures as with Na were followed except for the immersion in a solution of 10 g of toluene in 0.36 g of a toluene solution (25% as Sb) of Sb oxide. The metal amount was 0. 47% by weight. S: The same procedures as with Na were followed except for the immersion in a solution of 18.26 g of (NH₄)₂S solution (0.5% as S). The metal amount was 0.04% by weight.

Claims: 1. A crystalline aluminogallosilicate catalyst having aromatization activity for the preparation of a high-octane gasoline from a light hydrocarbon containing one or more paraffins and/or olefins, each having 2 to 7 carbon atoms, the catalyst having a skeleton comprised of SiO₄, AlO₄ and GaO₄ tetrahedra and being represented in terms of molar ratios of the oxides calcined at 500°C or higher by the formula: a M 2/n O · bAl₂O₃ · Ga₂O₃ · cSiO₂ · dH₂O wherein: M is at least one metal, n is the valence of said metal, a is a positive number of (b + 1) ± 3.0, b is from 1.17 to 6.09 inclusive, c is from 83.1 to 437.5 inclusive, d is from 1 to 200 inclusive, and the ratio c/b + 1 is from 38.295 to 61.707 inclusive, or a catalyst as defined above but wherein at least a portion of said metal M is replaced by hydrogen; and the catalyst having been treated with hydrogen gas. 2. A catalyst according to Claim 1, wherein M is a metal selected from an alkaline metal, an alkaline earth metal and a mixture thereof. 3. A catalyst according to Claim 1, in the hydrogen form. 4. A catalyst according to any preceding claim, wherein the amounts of aluminium and gallium in the skeletal structure of the aluminogallosilicate range from 0.1 to 5.0% by weight and from 0.1 to 10.0% by weight, respectively. 5. A catalyst according to any preceding claim, wherein said aluminogallosilicate is a product obtained by hydrothermally treating an aqueous mixture comprising a source of alumina and a source of gallia at a temperature and for a period of time sufficient to form crystals of said aluminogallosilicate. 6. A catalyst according to any one of Claims 1-4 wherein said aluminogallosilicate is a product obtained by inserting gallium or aluminium each into the skeletal structure of a crystalline aluminogallosilicate or a crystalline gallosilicate. 7. A catalyst according to any preceding claim, wherein said catalyst further includes one or more metals of Groups IIa, IIIa, IVa, Va, VIa, VIIa, Ib, IIb, IIIb, IVb, Vb, VIb and VIII carried on said aluminogallosilicate. 8. A catalyst according to Claim 7, wherein said metal component is Ca, Mg, La, Mn, Re, Ir, Pt, Zn, In, Se, Pd, Ni or V. 9. A process for the preparation of a high-octane gasoline, which comprises contacting a light hydrocarbon containing one or more paraffins and/or olefins, each having 2 to 7 carbon atoms, with a catalyst as defined in any preceding claim. 10. A process according to Claim 9, wherein said light hydrocarbon contains one or more paraffins and/or olefins having 5 to 7 carbon atoms in an amount of at least 50% by weight. 11. A process according to Claim 9, wherein said light hydrocarbon contains one or more paraffins and/or olefins having 2 to 4 carbon atoms in an amount of at least 50% by weight. 12. A process according to any one of Claims 9-11, wherein the high-octane gasoline produced has an octane number of at least 95, when determined by the research method, and contains aromatic hydrocarbons having 6-8 carbon atoms as a major component.

Inventors: HIRABAYASHI, KAZUO, KONDOH, TADAMI, NISHIJIMA, HIROAKI, SUZUKI, ISAO
Applicants: RESEARCH ASSOCIATION FOR UTILIZATION OF LIGHT OIL
Application year: 1987
Main classification: C10G35
IPC codes: C10G50, C07C5, C10G57, C10G35, B01J29, C07B61, C07C15