JPH0428418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing surface-modified zeolites with catalytic activity. The method comprises chemically modifying the zeolite by reaction with an organosilane under dry anhydrous conditions, the zeolite starting material having several sites available for reaction with the organosilane; It has several protected sites that do not react with the organosilane and remain as catalytically active sites. The organosilane to be selected is one that is capable of entering the pores of the zeolite and reacting chemically with the available sites present in the pores of the zeolite as well as with the available hydroxyl groups present on the outer surface of the zeolite. Must-have. To generate a silylated yet catalytically active (with protected sites) surface, the "as-crystallized" zeolite must be partially ionized with degradable ions such as _NH4 ⁺ . The decomposable ions are decomposed by calcination in air or an inert atmosphere at a high temperature of about 180° C. or higher, preferably about 200° C. or higher, and then cooled. One or both of firing and cooling is performed in a humid atmosphere. The zeolite is then heated in a dry environment at an elevated temperature, on the order of about 300°C or higher, the surface kept dry, and contacted with the organosilane at 25-500°C under anhydrous conditions. Chemically modified zeolites can be combined with catalytically active metal hydride components. Preferably, the organosilane-modified zeolite is heated to an elevated temperature in an inert or reducing atmosphere before or after depositing the catalytic metal component. This heating may be carried out as a separate operation or may be carried out in situ in an environment using a surface modified zeolite as a catalyst. The atmosphere used in each case is inert or reducing and is preferably hydrogen or contains hydrogen. When such independent or in-situ heating is performed, the silylated surface condenses and/or polymerizes to provide a stable surface. The temperature chosen to provide this stability is usually above the temperature of the subsequent catalytic process, but is preferably between 300 and 500°C, more preferably between 400 and 500°C. The chemically modified zeolites prepared by this method are effective hydrodewaxing catalysts for the production of high octane gasoline by selective paraffin cracking, the production of low pour point distillate fuel oils, and the conversion of methanol to gasoline. , Fischer-Tropsch synthesis, the isomerization of paraxylene and the synthesis of ethylbenzene, and the preferential acid-catalyzed reaction of linear (or slightly branched) paraffins or olefins. Surface silylation has been extensively studied since the early 1950s. Fleck U.S. Patent No.
No. 2722504 has the general formula: R ₁ R ₂ R ₃ SiX (however,
R ₁ R ₂ and R ₃ are organic moieties that cannot be hydrolyzed;
The organophilic nature of the catalyst and absorbent can be improved by treatment with a compound of the form It describes how to increase it. Although Fletzke did not describe the reaction,
Hydroxyl groups on insulating surfaces such as silica, alumina, magnesia and zeolites may interact with silanes in the following way. (s) Indicating Surface Silicon Many variations on the reaction of other silicon reagents with other surfaces (particularly silica) have been investigated. “Study of the Surface and Bulk Hydroxyl Groups of Silica by Infrared Spectroscopy and D ₂ O Conversion”
Bulk Hydroxyl Groups of Silica by
Infrared Spectra and D ₂ O Exchange)” [Kisclev et al., Trans.Farad.Soc. 60 , 2254
(1964)], “Reactions of Chlorosilanes with Silica
Surfaces)” [Hair et al., J.Phys.Chem. 73
#7, 2372, July (1969)], “Reactions of Chloromethyl Silanes with Hydrated Aerosilsilica.
"Hydrated Aerosil Silicas" [Armestead et al., Trans. Farad. Soc. 63 , 2549
(1967)], “Adsorption and reaction of methylchlorosilane on the Aerosil surface”.
Reaction of Methylchlorsilanes at
an′Aerosil′ Surface)” [Evans et al.
J.Catalysis 11 , 366-341 (1968)]. Recently, a patent was granted relating to the reaction of zeolites with organosilanes and the effects of this treatment. Kerr, U.S. Pat. No. 3,682,996 claims zeolite ester products (more accurately expressed as silicon esters) derived from the reaction of an aluminosilicate zeolite with a silane containing a usable hydrogen atom. . However, x is a number from 1 to 4, R is at least one organic group, and is any suitable aryl, alkyl, acyl, or aralkyl, and the pore structure accepts alkylsilane more easily than arylsilane. Alkyl groups are preferred. Apart from these silanes, Kerr mentions another silane that does not fit this formula: hexamethyldisilazane. Kerr does not disclose or claim the use of halogen-substituted silanes. All reactions described by Kerr occur under reduced pressure conditions, in which degassed H-type zeolite is contacted with pure gas or liquid organosilane at various temperatures. Kerr discloses, but does not prove or claim, that silylated zeolites may be used in catalytic applications, including "certain selective catalytic reactions." Allum, US Pat. No. 3,726,309, claims products derived from the reaction of inorganic materials containing hydroxyl groups, including aluminosilicates modified by treatment with organosubstituted silanes. Bound silicon ethers are produced by reaction with surface hydroxyl groups. US Pat. No. 3,658,696 to Shively claims an improved separation process from the reaction of organosilanes with zeolite molecular sieves. Substituting OH groups on the zeolite surface with silane groups greatly affects the adsorption properties of the molecular sieve surface. This is because hydroxyl groups form the main site of adsorption on the surface. In this case, choose a bulky silane that reacts only with the outer surface of the zeolite. Zhomov et al. used metal chlorosilanes to modify the properties of aluminosilicates used in the alkylation of phenols with propylene tetramers (Katal, Pererab, et al.
Uylevodorad, Syrya 1968(2)9) (Ref.Zh.Khim
(From 1969 Abstract No.4N196). Mitchell U.S. Patent No. 3980586
The claim in question includes alumina, silica alumina,
New products obtained by sequentially silylation, calcination and steam treatment of a group of substances consisting of aluminosilicates and aluminosilicates are described. The calcination is at a temperature high enough to remove any introduced organic or halogen substituents (unlike Kerr, Mitschiel uses a more common form of silane, including halogens). Continue long enough. The claims of Mitschiel US Pat. No. 4,080,284 describe novel materials useful in catalytic hydrogen conversion. Chen U.S. Patent No. 4002697 includes:
Silanization of ZSM-5 has been described to improve the yield of p-xylene obtained by methylation of toluene. In this case, a silane is selected that interacts only with the outer surface. Allen, U.S. Pat. Nos. 3,698,157 and 3,724,170, teaches that separation of _C8 aromatics can be improved by contacting an aluminosilicate adsorbent with a silane substituted with an organic group or a halogen. Are listed. The present invention relates to a method for producing surface-modified zeolites with catalytic activity. Such methods involve chemically modifying the zeolite by reaction with an organosilane under dry anhydrous conditions, the zeolite starting material containing several sites available for reaction with the organosilane and an organosilane. It has several protected sites that do not react with the silane and remain as catalytically active sites. The organosilane to be selected is one that is capable of entering the pores of the zeolite and chemically reacting with the available sites present in the pores of the zeolite as well as with the available hydroxyl groups present on the outer surface of the zeolite. Must-have. To generate a silylated yet catalytically active (with protected sites) surface, the "as-crystallized" zeolite must be partially ionized with degradable ions such as _NH4 ⁺ . The decomposable ions are decomposed by firing in air or an inert atmosphere at a high temperature of about 180° C. or higher, preferably about 200° C. or higher, and then cooled. One or both of firing and cooling is performed in a humid atmosphere. The zeolite is then heated in a dry environment at an elevated temperature, on the order of about 300°C or higher, the surface kept dry, and contacted with the organosilane at 25-300°C under anhydrous conditions. Chemically modified zeolites can be combined with catalytically active metal hydride components. Preferably, the organosilane-modified zeolite is heated to an elevated temperature in an inert or reducing atmosphere before or after depositing the catalytic metal component. This heating may be carried out as a stand-alone operation or may be carried out in situ in an environment using a surface-modified zeolite as a catalyst. The atmosphere used in each case is inert or reducing and is preferably hydrogen or contains hydrogen. When such independent or in-situ heating is performed, the silylated surface condenses and/or polymerizes to provide a stable surface. The temperature chosen to impart this stability is usually above the temperature of the catalytic process that follows, but preferably 300-500°C, more preferably
The temperature is 400 to 500°C. The chemically modified zeolites prepared by this method are effective hydrodewaxing catalysts for the production of high octane gasoline by selective paraffin cracking.
Production of low pour point distillate fuel oils, conversion of methanol to gasoline, Fischer-Tropsch synthesis, isomerization of paraxylene and synthesis of ethylbenzene, and linear (or slightly branched) paraffins or orphins. Applications such as preferential acid-catalyzed reactions have been found. The waxy oils that can be processed by the silylation catalysts of the present invention range from typical light middle distillate or heated oils with boiling points in the range of 200°C to 385°C to heavy lube oil distillates with boiling points of 580°C and deasphalted oils. Over vacuum residue. Preferred oils are light and middle distillate oils and roughinates, such as kerosene, lubricating oils or transformer oils. Hydrogen dewaxing with silylated zeolites is
Typically about 250-450°C, preferably 250-450°C
It is carried out at a temperature of 380°C, but lower temperatures are preferred so that non-selective cracking is reduced. Typical working pressure is 14-140Kg/
cm ² (200 to 2000 psig) H ₂ , preferably 21 to 70
Kg/cm ² (300-1000 psig) H ₂ , most preferably
28 to 49 Kg/cm ² (400 to 700 psig) H ₂ .
The feed rate is between 0.1 and 100 LHSV, preferably between 0.1 and 10 LHSV. Excess gas velocity is 1000 to
2000 SCF H ₂ /BBL, preferably 1000 to 5000 SCF H ₂ /BBL. The oils used to have catalytic properties (for hydrodewaxing) are detailed in Table 1. [Table] [Table] About zeolites The zeolites whose surface is modified in the present invention (with or without a catalytically active hydrogenation metal component depending on the application) are zeolite X, synthetic haujasite, zeolite Y, and mineral haujasite. Houjasite type (both natural or synthetic) including
It is. In the case of the present invention, silurization of zeolite Y is involved. Zeolite Y has large pores (7.1 Å) and is said to exhibit no shape selectivity. Zeolite Y is one of the largest 12-membered ring zeolites and can be used for hydrocracking (hydrocracking) to convert hydrocarbon molecules of various types and shapes.
hydrocracking). One useful feature of this type of structure is that it may have a three-dimensional network of connected supercages;
Its three-dimensional network simply adsorbs organosilanes (ACS Advances in Chem).
“Modification” by McAteet et al., Volume 121 (1973).
Of HY Zeolites by Reaction
With Tetramethylsilane (Modification of
HY Zeolites by Reaction with
“Molecular Sieves” edited by WMMeier and JBUytlerhoeven
and J.C.S.Fualaday (JCS)
Faraday, Vol. 175, No. 9, p. 2221 (1979), Barrer et al.
Sorption of Hydrocarbons
and in Silanated and Unsilanated Partial H
- Forms of Zeolite Y)"), but also three-dimensional networks into which hydrocarbon molecules (e.g. waxes) can readily diffuse. However, the above references do not teach, suggest or imply such a use. No. In general, each of these phosiasite zeolite systems has larger pores than ZSM-5 and can be improved by silylation, making the system highly hydrophilic "as crystallized." ZSM
-5 is a hydrophobic zeolite with medium pores and effective for catalytic dewaxing. The advantages of the zeolite surface modification method herein are demonstrated by catalytic dewaxing of waxy hydrocarbon oils. Regarding Organosilanes In the present invention, zeolites are treated with organosilanes under specific conditions, which will be explained in more detail below, in order to effectively carry out condensation and polymerization. The organosilanes employed in the preparation of catalysts useful in the process of this invention are as follows. _{SiR y _ _ _ _ _} having; Trimethylsilane, N-methyl-N-trimethylsilyltrifluoroacetamide. The most useful organosilane in this study is hexamethyldisiloxane (HMDSO). Method for producing modified zeolite The purpose of treating zeolite catalyst with organosilane is to convert from hydrophilic to hydrophobic type and reduce the size and volume of zeolite pores. If zeolite is templated with an organic framework structure such as tetramethylammonium ion
If crystallized with ions, the zeolite must first be treated to remove these species. Generally, the zeolite is removed with an organic framework template and/or forms sufficient moieties for silylation using _NH4 ⁺ ion exchange or other methods known in the art. To form enough pieces, fire. Zeolites containing organic framework regulators (such as tetramethylammonium) may be used, e.g., before or after calcination to decompose the organic framework regulators.
Exchange with a degradable cation such as NH ₄ ⁺ and remove the cation. For hydrogen consuming process applications, it is preferred to incorporate a catalytically active hydrogenation metal component (preferably the metal is a cation) into the zeolite. In this case, the conversion to the silylated active type can be carried out before blending the metal, but it is best to first blend the metal into the NH ₄ ⁺ form of the zeolite and then sinter the zeolite to make it the reactive type. preferable. The metal salt is then reduced to its elemental state by known techniques. Oxides, sulfides and mixtures thereof of Group and/or Group metals may be used, but metals are preferred. It is sometimes useful to have 0.1 to 2.0% polymerization, preferably 0.1 to 1.0%, most preferably 0.2 to 0.5% pt and pt, based on dry zeolite. Metal formulation as well as ammonium exchange may in some cases be performed using H ₄ EDTA leaching or other known techniques.
It may be performed after the operation to increase the SiO ₂ /Al ₂ O ₃ ratio. Although metal compounding can be carried out after the silylation step (details will be described later), it is preferably carried out before the silylation step. Generation of Reactive Sites After exchanging the zeolite and depositing further metal salts if necessary, the zeolite is treated to generate sites that react with organosilane. The sites that react with organic silanes are "isolated hydroxyl groups" and "strained crosslinking" sites. As used herein, it will be understood that the term "reactive site" includes both types of sites. Independent sites are non-adjacent hydroxyl sites such that interactions between hydroxyl groups are minimal. "Strained cross-linking" sites are created when adjacent hydroxyl sites interact when heated in a dry environment to dehydroxylate the surface. In zeolites with low SiO ₂ /Al ₂ O ₃ ratios (eg high site densities), care should be taken to employ methods that generate the desired reactive sites while protecting the catalytically active sites. Isolated sites can be produced by calcining the ammonium-type zeolite in a dry environment, such as dry hydrogen, and maintaining a moisture-free surface (ie, a dry environment) before and during silylation.
Alternatively, isolated hydroxyl sites can be created by performing minimal cation exchange to create a lower density of hydroxyl groups, reducing the possibility of hydroxyl groups interacting with each other. In other words, the density of hydroxyl groups can be adjusted by the degree of cation exchange.
The higher the degree of cation exchange, the higher the density of hydroxyl groups generated during subsequent calcination. Alternatively, increasing the silica/alumina ratio of the zeolite reduces the number of hydroxyl sites and minimizes interactions between hydroxyl groups. Another type of reactive site, a strained crosslinking site, results from dehydroxylation of strongly interacting or hydrogen-bonded hydroxyl sites. Hydrogen-bonded hydroxyl sites are first generated by calcining ammonium type zeolite at a temperature of preferably about 180°C or higher, more preferably about 200°C or higher, decomposing the ammonium type, and then cooling to a temperature of 100°C or lower. . Either or both of the calcination and cooling steps are carried out in a humid atmosphere, for example in humid air, or if both the calcination and cooling are under anhydrous conditions the resulting zeolite is equilibrated in a humid atmosphere. If the number of hydroxyl groups thus obtained is large enough, they are close enough to interact by hydrogen bonding. The density of hydroxyl sites as mentioned above is controlled by the degree of cation exchange, so the higher the degree of cation exchange, the greater the density of hydroxyl sites during subsequent calcination.
In zeolites with low silica/alumina ratios, the probability of forming hydrogen-bonded hydroxyls increases. Such hydrogen bonded hydroxyl sites are substantially non-reactive with the silylating agent. However, this surface can be removed in a dry environment by approximately
When heated again to temperatures above 300° C., such sites collapse releasing chemical water out of the strained bridges. This site reacts with the silylating agent. Dehydroxylation can be expressed as follows. A mixture of reactive sites (independent hydroxyl groups and strained crosslinking sites) can be created by varying drying conditions and activation temperatures. Silylation Silylation is performed by contacting the zeolite with a vapor or liquid organosilane under anhydrous conditions or by dissolving the organosilane in a dry organic solvent such as hexane, heptane, naphtha, lubricating oil, etc. 20 depending on the zeolite being treated and the silane used
This is carried out by contacting the zeolite with the solution at ~500° C. in the presence or absence of a metal hydrogenation component (more detailed below). The silylation liquid contains 0.01 to 20% by volume of silane, preferably 1
Contains ~5% silane by volume. If the organosilane is not reacted directly with the surface as a vapor or liquid, it may be used as an organic solution (preferably using a non-polar, non-aromatic solvent as the solvent), where the water content is approximately
Must not exceed 10ppm. The silylation solution is approximately
It contains 0.01 to 20% by volume, preferably 1 to 5% by volume of silane. The total free water content in both the zeolite and the solvent should not exceed about 10 ppm. Acetone, toluene, ethyl acetate, 1,4-dioxane, etc. are all unsuitable solvents because they react with sites on the zeolite under the conditions required to form a stable silylated surface. On the other hand, n-hexane, n-pentane, carbon tetrachloride, white oil are suitable as solvents, and the hydrocarbon oils of the feedstock used in the catalytic process itself can also be used as solvents. Attention must be paid to the dryness of the solvent, as water hydrolyzes the silylated molecules (at least hexamethyldisiloxane (HMDSO)
It's not just because (it only happens slowly). The problem is that water can interact with the reactive sites of the zeolite, thus potentially altering or inhibiting the reaction of HMDSO or other silylating reagents with the reactive sites (see discussion above,
hydrogen-bonded hydroxyl). Surface moisture can block access of the silylating agent to internal reactive sites, limiting silylation to external reactive sites. The silylation is preferably carried out after loading the catalyst with a metal, followed by partial thermal decomposition (air calcination) of at least the ammonium ion moieties into hydroxyl moieties and complete decomposition of the organic nitrogen skeleton structuring agent. An initial reaction at room temperature with an isolated site is possible, as described in U.S. Pat. No. 3,682,996.
Trimethylsilyl (TMS) groups form surface "ether" bonds. For example, the reaction between a reactive isolated hydroxyl site and HMDSO is expressed as: Si(s)-OH+( _CH3 ) _3Si -O-Si( _CH3 )
₃ → 2 [si(s)-O-Si(CH ₃ )] + H ₂ O The reaction between the strained cross-linking site and HMDSO is, for example, as follows: It is expected that the silylated species produced by the above reaction series will undergo some type of condensation polymerization reaction as the temperature increases. Possible condensation products are as follows. The composite surface is expected to be stable in hydrogen atmosphere up to 550°C. This type of surface is thus different from the surfaces described in both U.S. Pat. No. 3,622,996 (pendant silyl groups) and Mitschiel U.S. Pat.
This is similar to the secondary reaction product observed for pine cattail in the reaction of zeolite Y and tetramethylsilane (ACS Advances in Chemistry).
Sieves No. 121, "Molecular Sieve" by Meier and Uytterhoeven). Since the internal reactive sites in large-pore zeolites can be relatively easily replaced by silanes (silanes can easily enter the pores of the zeolite), the initial silylation contact temperature ranges from low to moderate 25-200°C. Temperature is fine. The final state of the silylated surface (i.e. the extent of condensation-polymerization) is determined by the silylation step, the subsequent activation step,
Or it is determined by the highest temperature experienced by the surface in any process, for example when using a catalyst in oil. Condensation-polymerization reactions between adjacent silyl groups, as well as between silyl groups and unreacted sites, begin at about 25°C and become more intense as the temperature increases. The condensation-polymerization reaction may be carried out as a separate operation or may be carried out in situ in a catalytic environment (as a direct result of a catalytic process carried out at elevated temperature). In any case, the atmosphere used is inert or reducing, preferably hydrogen or a hydrogen-containing atmosphere (particularly if hydrogen is used in the catalytic process). The heating in this case is carried out in such a way as to form a stable surface. To provide such stability, the heating temperature is generally set at or above the temperature used in the subsequent catalytic process, preferably about 300-500°C, more preferably about 400-500°C. Protection of hydroxyl sites Although changing the pore volume and adsorption properties is highly desirable and can be achieved by silylation of reactive sites, it is important to protect some hydroxyl sites so that the modified catalyst is ultimately active. It is also important to do so. It is necessary to strike a balance between sufficiently restricting the catalytically active acidic hydroxyl sites and retaining these sites to some extent. If the organosilane used easily accesses the pores of the zeolite and silylates all the hydroxyl groups inside and outside the zeolite, the catalyst may become inactive. In such cases, a method is required to generate and protect a certain amount of hydroxyl groups. For zeolites such as Zeolite Y, such protection involves isolated/strained bridging hydroxyl sites (i.e., sites that react with organosilanes) and hydrogen bonding sites (i.e., sites that do not react strongly with organosilanes). This is done by creating a mixed state. This condition is achieved by calcining (preferably above about 180°C, more preferably above about 200°C) a cation-exchanged (e.g. NH ₄ ⁺ ) zeolite to about
It can be obtained by cooling to below 100℃,
The calcination and/or cooling may be performed in a humid atmosphere (eg, humid air) or, if the calcination/cooling is carried out in an anhydrous atmosphere, the cooled zeolite may be equilibrated in a humid atmosphere (eg, humid air). If there are too many non-reactive hydrogen-bonded hydroxyl sites (these do not react with organosilane),
This surface may be subjected to dehydroxidation conditions to obtain some strained crosslinking sites that will react with the organosilane silylating agent. Any hydrogen-bonded hydroxyl groups remaining after dehydroxylation can be utilized as hydroxyl groups with catalytic activity. Another method of protection includes blocking potential hydroxyl sites with cations. For example, a sodium-type zeolite is partially exchanged with an ammonium salt solution, calcined to generate isolated hydroxyl sites, treated with a silylating agent under dry conditions, and then re-exchanged and calcined to create new reactive hydroxyl sites. may be caused. Catalysts Two series of catalysts derived from zeolite Y were investigated. These batches are here named Substance A and Substance A ^* . Substance A = Na Zeolite Y from Union Carbide Corporation
Zeolite Y obtained in the Na form has the following oxidation formula: Na ₂ O.Al ₂ O 3.4.4SiO 2.8.9H ₂ O and the corresponding unit cell _formula is: _{Na 60 [} (AlO ₂ ) ₆₀ ( SiO ₂ ) ₁₃₂ ].250H ₂ O Material A-1 Material A was converted in 0.5N NH ₄ NO ₃ with a 10 volume excess solution at reflux for 2 hours, then filtered and washed with water. The crystals were reslurried with 2 volumes excess of dilute ammonia aqueous solution (PH 10) to give a p.d.
A dilute solution containing (NH ₃ ) ₄ Cl ₂ was added dropwise at room temperature over 5 hours to deposit a nominal 0.25% by volume of palladium. After washing with water and filtering, the sample was dried at 120°C (1 hour). This sample contains _NH4 ⁺ ions. Catalyst A-2 Humid air (laboratory air at ambient temperature)
When A-1 was calcined at 500° C. for 1 hour in a NH 4 + oxide solution, an NH ₄ ⁺ -free catalyst having the following oxide composition was obtained. _{The 0.45Na2O.Al2O3.4.4SiO2} powder was processed, crushed and sieved to 7-14 mesh (Tyler), _charged into _the reactor and reduced at 400C _H2 . HMDSO Modified A Catalyst Catalyst A-1M (a) This catalyst was prepared from material A-1. Catalyst A
-1 is air fired at 250℃, air cooled, compressed,
Sift to 7 to 14 pieces (Taylor),
Then, it was charged into the reactor. Here, the substance is 200
Dry in _N2 for 1 hour at 200 °C and then in _H2 for 2 h at 200 °C.
Dry at 40°C, 5% HMDSO/Primol
185 at 1 v/v/h for 10 hours, and the catalyst was heated at 500° C. in H ₂ before the final feed. Catalyst A-1M(b) 160 hours, flow (Western Canadian
600N), the catalyst (A-1M(a)) was heated with H ₂
Cool to 250℃ in medium, add 1v/5% HMDSO solution by volume.
Passed over the catalyst for 5 hours at 1 v/h. The feedstock was recharged and the temperature increased to 350°C. Substance A ^* = Na Zeolite Y The other sample of Zeolite Y powder was the Na type with the following oxide composition 1.1Na ₂ O.Al _{2 O} 3.4.7SiO ₂ and was manufactured by Union Carbide Corporation. Corporation). It has been designated herein as substance A ^* . Substance A ^* -1 The obtained substance A ^* is 10 times (volume) or more 2N-
2 by refluxing with an aqueous NH ₄ NO ₃ solution for 1 hour.
The composition of the product obtained by the repeated exchange was as follows. The 0.23Na ₂ O Al ₂ O ₃ 4.7 SiO ₂ sample was washed in deionized water until free of No ₃ ⁻ , then replaced with a sufficient amount of a dilute solution of pd(NH ₃ ) ₄ Cl, and then washed with dry zeolite. A pd of 0.25% by weight was produced. The samples were then washed with deionized water, oven dried at 120° C. for 1 hour, and allowed to equilibrate in laboratory air at room temperature. Catalyst A ^* -1 Substance A ^* -1 is pressurized, crushed, sieved through a 7-14 mesh (Tyler), and charged into a reactor to produce _H2
The mixture was heated to 400°C. HMDSO-modified A ^* catalysts (A ^* -1M _to ^A* -8M) Each of the A ^* catalysts treated with HMDSO may be modified with different concentrations of _NH4NO3 to change the degree of exchange. ^* All were prepared in the same manner as -1. 0.25% Pd was blended in the same manner as substance A ^* -1. Table 2 lists the steps used to make these catalysts. [Table] Some samples were placed in dry air at 0.028 m ³ (1 foot).
³ ) was heated in the Matsufuru furnace for 1 hour. The dry air had a moisture content of less than 50 ppm and a flow rate of 0.084 m ³ /hour (3 feet ³ /hour). Each such air-fired sample was removed from the oven while hot and allowed to cool to room temperature in a humid laboratory chamber. The remaining samples were not air fired, but were pressurized and washed.
The reactor was sieved through ~14 meshes and heated at 400 °C in dry _H2 . For all samples, silylation was performed after this final drying step. In all cases except Catalyst A ^* -8M, which is listed separately, a 5% solvent solution of HMDSO (solvent: Pirimol 185 white oil or hexane) was used at elevated temperature and 3.5 Kg/cm ² (50 psig) of H HMDSO denaturation was performed at ₂ pressures. HMDSO
The solution was charged at a rate of 15 v/v/h to the point of leakage, then the rate was reduced to 5 v/v/h for 2.5 hours.
Pure solvent was then introduced for 15 minutes, after which the H ₂ gas rate was increased from 0 to 10 cfm, and after 1.5 hours the solvent was turned off and H ₂ gas continued to be introduced into the reactor initially at the silylation temperature for 1.5 hours. The temperature was then increased to 400°C for 1 hour. A list of silyl treatment conditions is shown in Table 2. After silylation, the reaction vessel was cooled to 200° C. and the feedstock was introduced. Conditions are laboratory specific.
5000SCF/B, 3000SCF/B per pilot
42Kg/ ^cm2 (600psig) of pure _H2 at _H2 speed
It was 1.0v/v/h. 1R Monitoring of Organosilane Reactants Because zeolites are transparent to infrared radiation above 1300 cm ^-1 where valence vibrations occur, infrared transmission spectroscopy is an excellent means of monitoring changes in the type and density of zeolite acidic sites. be. 2.5cm of 40-50mg
Using a catalyst compressed into a disk with a diameter of 140
A high transmittance spectrum of the catalyst was obtained by degassing at °C to remove physically bound and hydrogen bonded water. All spectra shown herein were recorded on a Beckman 4240 infrared spectrometer at room temperature. Silylation of Zeolites Figures 1 to 4 demonstrate the importance of having silylation reactive sites. FIG. 1 shows that HMDSO in the gas phase does not easily react with hydroxyl group-type zeolite Y whose hydroxyl groups are hydrogen-bonded. It can be seen that little or no change has occurred in the zeolite hydroxyl band centered around 3600 cm ^-1 . This wide band characteristic (no clear peak) indicates the hydrogen groups interacting (hydrogen bonding) in the supercage and subcage (truncated octahedron) of zeolite Y. Such hydrogen-bonded hydroxyl groups are thought to have arisen (in this case) due to the presence of moisture on the zeolite Y surface, but do not react with the silylating agent (in this case HMDSO). On the other hand, a distinct band of non-interacting hydroxyl species occurs when A-1 (ie NH ₄ ⁺ type zeolite Y) is decomposed under dry conditions (Figure 2). Bands caused by stretching vibrations of an external hydroxyl group at 3740 cm ^-1 , a supercage hydroxyl group at 3650 cm ^-1 , and a B-cage hydroxyl group at 3550 cm ^-1 have already been fixed by Uitzterhoven et al. (J.Phys. .Chem.
69(6)2117 (1965)). It is clear that none of the hydroxyl group species are hydrogen bonded, and as is clear from the disappearance of the hydroxyl group band and the appearance of a new band derived from the C-H stretching mode at 2980 cm ^-1 , these hydroxyl group species are 25 Reacts strongly with HMDSO at °C. When the material is further degassed and heated, traces of the hydroxyl band completely disappear, and the strength of the C--H band decreases due to condensation-polymerization. Another example of the effect of surface pretreatment of material A-1 on the degree of silylation is shown in FIG. A-1 is humid air (laboratory air with environmental humidity)
Calcinate at 500°C for 1 hour, cool to room temperature (to form A-2), then degas at 140°C.
A mixed state of hydrogen-bonded hydroxyl groups and independent hydroxyl groups occurred (Fig. 3A). The number of internal isolated hydroxyl groups is significantly higher in A-2 (NaY exchanged in 0.5N ammonium nitrate) than in the example shown in Figure 1 (NaY exchanged in 2.0N ammonium nitrate). This surface was then treated with 15 Torr dichlorodimethylsilane vapor (a highly reactive silylating agent) for 12 minutes at room temperature.
and then degassed again at 140° C. for 1 hour to 5×10 ⁻³ Torr. The isolated site completely disappeared, and a new band indicating silylation appeared at 2980 cm ^-1 and
It appeared at 2920cm ^-1 . However, the number of hydrogen-bonded hydroxyl gases did not change (Figure 3B). This example shows that when a hydrogen-bonded hydroxyl group and an isolated hydroxyl group are generated at the same time, it is clear that among these two types of hydroxyl groups, only the isolated hydroxyl group reacts with the silylating agent added to the system, so it is difficult to accurately determine the degree of silylation. This shows that it can be prepared as follows. Unreacted hydrogen-bonded hydroxyl groups remain and provide catalytic activity. However, the surface containing hydrogen-bonded hydroxyl groups may be activated to react with the organosilane. This can be achieved by dehydroxylating the hydrogen-bonded hydroxyl groups. This is shown in Figure 4. isolated hydroxyl group, NH ₄ ⁺ ,
and a surface where hydrogen-bonded hydroxyl groups coexist (Figure 4A)
at high temperature (500°C) for 45 minutes under reduced pressure (less than 10 ^-3
C), yielding a small number of isolated sites and (by inference) a large number of distorted cross-linked sites, with no hydrogen bonding sites present (Figure 4B). That is, this surface has been dehydrated and oxidized. Next reaction of this surface with HMDSO vapor yields a large number of chemisorbed silyl species (bands at 2980 and 2920 cm ^-1 ), a number that was predicted based on the assumption that only isolated hydroxyl groups were reacted. (as shown in Figure 2)
(compare with the band intensities of 2980 and 2920 cm ^-1 ). Thus, for the purposes of the present invention, at least one of the two types of reactive sites described above must be generated to facilitate silylation. Decomposition A-1 (hydrogen type, isolated hydroxyl group) is HMDSO
Evidence for complete silylation by pyridine is that when adsorption experiments of pyridine vapor are performed on this modified surface, adsorption occurs as hydrogen-bonded pyridine and Lewis-adsorbed pyridine, but proton exchange occurs to generate pyridinium ions. This shows that there is no significant Brønsted adsorption site (no band at 1540 cm ^-1 ) (Figure 5). The fact that all the Brönsted sites in zeolite Y may have been removed means that the Brönsted sites are generally considered to be necessary for the C-C cleavage reaction, so there is a risk that the hydrogen decomposition ability of the zeolite may be destroyed. It means that there is. Therefore, zeolite Y and other low silica/
For alumina ratio zeolites, it is suitable to protect the catalytically active hydroxyl groups, and the system thus organized can function as a diffusion-selective yet catalytically active surface. In one embodiment, the cations of Na zeolite Y are partially exchanged and calcined to generate isolated hydroxyl groups, treated with a silylating agent under dry conditions, and then re-exchanged to expose new sites. let Original cation species (in the case of Na-type zeolite Y
The level of exchange (eg ammonium exchange) of Na) may also determine the number of isolated hydroxyl species and thus the degree of silylation of the hydroxyl groups. When a small number of hydroxyl groups are generated, it is sufficient that the hydroxyl groups are sufficiently far apart to prevent hydrogen bonding even if decomposed in humid air (Figure 3). If the exchange level is high, calcination of the surface following exchange and cooling under moist conditions will result in more hydrogen bonding species. Alternatively, NH ₄ ⁺ can be used as the blocking ion. In this case, the relative number of NH ₄ ⁺ to acidic hydroxyl sites can be adjusted by the firing temperature. The catalyst after silylation is, for example, 500
The parts can be restored to their original state by post-firing at ℃, and Na
There is no need to replace it again as in the case of blocking. In this case, it is important to ensure that the hydroxyl sites generated by NH ₄ ⁺ decomposition are not completely consumed by crosslinking reactions that may occur between adjacent silyl species. A preferred method of preserving hydrogenolysis active sites in low silica/alumina ratio zeolite catalysts (e.g. Zeolite Y) is to create a mixture of hydrogen bonding hydroxyl sites and isolated hydroxyl sites. A preferred method of achieving this objective is to first partially decompose the NH ₄ ⁺ type zeolite Y and then generate hydrogen-bonded hydroxyl groups by exposing the newly formed hydroxyl groups to moisture. This is what happens with A series catalysts when, after calcination in humid air, the calcined material is cooled to room temperature in humid air. Even if the calcination is carried out under anhydrous conditions, the result is the same if the subsequent cooling is carried out in a humid atmosphere (e.g., humid air, such as laboratory air with ambient moisture, or any other atmosphere that provides moisture). is obtained. When firing is performed under a humid atmosphere, subsequent cooling may also be performed under a dry atmosphere. Preferably, at least the cooling is carried out in a humid atmosphere, or the zeolite is equilibrated in at least a humid atmosphere after calcination and cooling. The amount of moisture and the period of time that the zeolite is exposed to the humid atmosphere is determined by the degree to which the resulting hydroxyl groups are hydrogen bonded. When this surface is then dried and the remaining NH ₄ ⁺ sites are decomposed in a dry environment, the hydrogen-bonded hydroxyl groups are dehydroxylated to produce isolated (non-hydrogen-bonded) hydroxyl groups and distorted crosslinking sites. These two sites can react together with HMDSO or other silylating agents if dry conditions are maintained. The ratio of hydrogen bonding sites to reactive sites (isolated hydroxyl groups and strained crosslinking sites) determines the degree of silylation. The hydrogen-bonded hydroxyl group remains after silylation,
It acts effectively as a hydrogenolysis site. but,
All that is required is that there be some protected hydrogen-bonded hydroxyl groups that do not react with the silylating agent and some generated reaction sites (independent hydroxyl groups and/or strained cross-linking sites) that react with the silylating agent. ) exists. All silylation reactions occur on metal-loaded zeolite Y
Although it is worth noting that what is done above is not critical to the successful implementation of the present invention. HMDS and HMDSO
The reactivity and proportion of the reaction between Pd and Y-type material are independent of the presence of this metal, at least until the amount of Pd is 0.5% by weight. Catalytic Dewaxing The following example shows that the Pd zeolite Y catalyst can be transformed from a non-selective hydrocracking catalyst to a catalyst that selectively dewaxes lubricating oils. The examples support the spectroscopic evidence described above while demonstrating other limitations.
(a) air fired (without subsequent drying);
The surface of NH ₄ ⁺ type zeolite Y is a silylating agent.
Does not react extensively with HMDSO. (b) heated in a dry atmosphere and then silylated.
The NH ₄ ⁺ type zeolite Y surface is not an effective catalyst. (c) The most effective catalysts are those that are first air-calcined in a humid environment (or air-calcined in a dry environment and then exposed to moisture), dried at temperatures above about 300 to 350°C, and then silylated. be. Performance examples of untreated catalysts A-2 and A ^* -1 1 Catalyst A-2 Untreated catalyst A-2 was mixed with Western Canadian 600N waxy roughinate at 300°C, 325°C,
and 4.14MPagH ₂ , 1.0v/v/ at 370°C
The contact was made under conditions of h (Table 3). The remaining oily fraction (ie, the product after stripping) was still very waxy, indicating that the process was not shape selective to the input molecules. In fact, when performing silica gel separation and measuring the wax content by solvent separation, the product has a higher concentration of saturated compounds than the feedstock, indicating that A-2 is actually antiselective towards waxes. It shows. Aromatic compounds and polar compounds reacted preferentially. Because aromatic and polar compounds generally belong to the bulkier class of molecules in the feedstock, molecules of any size and type can approach the hydrocracking surface and cause the product to boil in approximately the same range as the feedstock. The fraction is considered to be low. The oil yield at a reactor temperature of 370°C was only 35%. These results were all expected for a large pore, hydrophilic, acidic surface. It should be noted that this catalyst contained some interaction sites and some dehydroxylation sites since it was calcined in humid air before drying. [Table] Example 2 Catalyst A ^* -1 Like catalyst A-2, untreated catalyst A ^* -1 also has insufficient hydrodewaxing catalyst performance, but unlike A-2, it is generally a hydrocracking catalyst. The performance as a fuel cell is also insufficient (Table 4). That is, Western Canadian 600N is poorly converted by hydrogenolysis of any type of molecule. Catalyst A ^*
Since -1 mainly contains only isolated sites (it was not air calcined), it will be clear that this alone is not effective in the catalytic hydrogenolysis reaction. The superior hydrogenolysis activity of A-2 is clearly related to the air calcination/moisture exposure step during manufacturing that results in the creation of interactive hydroxyl sites. It is these sites that are necessary for hydrogenolysis activity. Performance examples of silylation catalysts 3 Catalysts A ^* -1M and A ^* -2M These catalysts have very little activity as hydrocracking catalysts and have very low pour points relative to Western Canadian 600N. (Table ⁵ ). Since neither catalyst was air calcined or exposed to moisture prior to silylation, no sites responsive to hydrogenolysis were generated. Although considerable silylation occurred on both catalysts,
It has few available catalytic active sites, making it unsuitable for applications such as hydrocracking. Example 4 Catalyst A-1M(a) The A-1 material was actually modified twice. Substance A was first modified by calcination at 250° C. in humid air. Based on the results shown in Examples 1 and 2, the catalyst is expected to have active hydrogenolysis sites. However, the surface is not sufficiently dry before silylation and is heated only at 200 °C in dry N ₂ and dry H ₂ . Under such circumstances, a large number of interaction sites are expected to exist before and during silylation. According to IR studies, silylation by HMDSO should be minimal. In fact, as shown in Table 6, A-1M(a) is an active hydrocracking catalyst, but has only limited selectivity for wax removal from Western Canadian 600N. A-1M(a) is the same as untreated catalyst A-2 except for a slight drop in pour point.
behaves similar to. Example 5 Catalyst A-1M(b) This example shows that a surface containing mainly interaction sites (A-1M(b)) can be very easily dehydrooxidized under typical drying conditions associated with a hydrocracking environment. It shows that it can be done. A-1M(a) after 160 hours treatment on Western Canadian 600N
When treated with HMDSO, catalyst A-1M(b) becomes active for hydrodewaxing (Table 6). At 350℃, 160 hours treatment on feedstock,
Since most of the interacting hydroxyl groups in (A-1M(a)) that do not react with HMDSO are dehydroxylated,
More silylation occurs with HMDSO treatment,
The surface is easily silylated (A-1M(b)). As a result, performance improved dramatically. Under mild reactor conditions (350°C) the yield of oil product was relatively high and the pour point decreased by -2°C. In this type, zeolite Y behaves as a selective hydrodewaxing catalyst, and the relatively low reactor temperatures required are evidence of superior catalytic site retention. The following example illustrates a preferred procedure for air-calcining and cooling _NH4 type zeolite Y (with humid air exposure during one or both of such steps) and heating to above about 350°C in a dry environment prior to silylation. . Example 6 Catalysts A ^* -3M and A ^* -4M The catalytic dewaxing activity of catalysts A ^* -3M and A ^* -4M was investigated on a number of different waxy feedstocks over a range of temperatures (Table 7). and 8
table). These two catalysts have different degrees of exchange (A ^* −
3M is Na/Al=0.45; A ^* −4M is Na/Al=0.23)
Both showed catalytic activity when derived from Western Canadian wax oil (A ^* -3M had a lower activity by about 20°C than A ^* -4M). In both cases, the catalysts were dry air calcined and equilibrated at room temperature in humid air. It was then heated to 400 °C in _H2 . The resulting material was silylated but behaved as an active hydrogen dewaxing catalyst since the catalytic active sites were retained. Example 7 Catalysts A ^* -5M and A ^* -6M This example demonstrates the existence of the lowest effective air calcination temperature required when subsequently silylated with HMDSO. Both A ^* -5M and A ^* -6M exhibit hydrogen dewaxing activity with respect to Western Canadian 150N (Table 9), but A ^* -6M is more selective (i.e., producing a given pour point). high yield of dewaxed oil in relation to products). When manufacturing A ^* −5M,
The air calcination temperature of 180°C before the HMDSO silylation step is not high enough. Pre-activating
A product with even better performance was obtained by air firing at 200°C (A ^* -6M). Example 8 Contact A ^* -7M This example shows that the solvent used to transport the silylating agent can be a light hydrocarbon, in this case n-hexane. When silylated with HMDSO,
In this case, an active hydrogen dewaxing catalyst was obtained (No.
Table 10). Example 9 Catalyst A ^* -8M In this example, even after using the catalyst under the conditions of hydrogenolysis of Western Canadian 600N,
Showing that sites of silylation may still exist (see
Table 11). Both native and denatured samples were examined. The unmodified sample was an active but non-selective hydrogenolysis solvent. After 14 hours of feeding, 5% by volume of HMDSO in 600N oil (as solvent) at 325°C.
The solution was denatured. The modified catalyst was selective when new feedstock was introduced at 350°C. This shows that in-situ silylation of zeolite Y is possible. The zeolite Y base was dry air calcined, equilibrated at room temperature in humid air, and heated to 400° C. in H ₂ . The zeolite is capable of silylation even after catalytically active hydroxyls are formed on the zeolite surface and the hydroxyls participate in the catalyst. [Table] Yield [Table] [Table] [Table] [Table] [Table] [Table] [Table]

[Brief explanation of drawings]

FIG. 1 is an infrared spectrum of the vapor phase reaction of hexamethyldisiloxane (HMDSO) and H-zeolite Y (containing hydrogen-bonded hydroxyl groups). FIG. 2 is an infrared spectrum of the vapor phase reaction of HMDSO and H-zeolite Y (including isolated sites). FIG. 3 is an infrared spectrum of the vapor phase reaction of H-zeolite Y containing mixed isolated and hydrogen-bonded hydroxyl groups with dicyclodimethyltran. Fourth
The figure shows an infrared spectrum of the vapor phase reaction of HMDSO with H-zeolite Y containing reactive moieties comprising a mixture of isolated hydroxyl groups and sites obtained by dehydroxylation of hydrogen-bonded hydroxyl groups. Figure 5 shows
1 shows an infrared absorption spectrum of pyridine on HMDSO-modified catalyst A-1.

Claims (1)

[Claims] 1. A method for surface modification of large pore zeolites to produce materials retaining sufficient catalytic active sites suitable for use as catalysts, comprising: chemically modifying the zeolite by reacting with the organosilane such that the zeolite starting material to be modified does not react with the organosilane with several sites available for reaction with the organosilane. The organosilane can enter the pores of the zeolite and have effective reactive sites present in the pores of the zeolite as well as the outer surface of the zeolite. A method characterized in that it is capable of reacting with reactive sites present on the surface. 2. In the method described in claim 1,
First, the cation-exchanged zeolite is calcined and cooled (with at least one of such calcining and cooling being carried out in a humid atmosphere) to form protected sites so as not to react with the organosilane; obtaining a mixture of protected sites and effective reactive sites on the zeolite by calcining and cooling the zeolite under anhydrous conditions before reacting it with the organosilane under anhydrous conditions; A method characterized by: 3. In the method described in claim 1,
The cation-exchanged zeolite is first calcined and cooled under an anhydrous atmosphere, and then the zeolite is exposed to a humid atmosphere to form protected sites from reacting with the organosilane, and then the zeolite is anhydrous. A method characterized in that a mixture of protected sites and active reactive sites is obtained on the zeolite by calcination and cooling under anhydrous conditions before reacting with the organosilane under conditions. . 4. In the method described in claim 2,
A method characterized by performing the process at an initial temperature of approximately 180°C or higher. 5. In the method described in claim 3,
A method characterized by performing the first firing at a temperature of approximately 180°C or higher. 6. In the method described in claim 2,
A method characterized in that the cation-exchanged zeolite is an ammonium-type zeolite, and the first calcination is performed at a temperature of about 200°C or higher, and the subsequent anhydrous calcination is performed at a temperature of about 300°C or higher. 7. In the method recited in claim 3,
A method characterized in that the cation-exchanged zeolite is an ammonium-type zeolite, and the first calcination is performed at a temperature of about 200°C or higher, and the subsequent anhydrous calcination is performed at a temperature of about 300°C or higher. 8. A process for surface modification of large pore zeolites to produce materials retaining sufficient catalytic active sites suitable for use as catalysts, comprising the steps of partial cation exchange of the zeolites, calcination under anhydrous conditions and The cooling step removes the organosilane which can enter the pores of the zeolite and react with the available reactive sites present in the pores of the zeolite as well as the reactive sites present on the outer surface of the zeolite. reacting the zeolite under anhydrous conditions, reexchanging the resulting silylated zeolite, and calcining the reexchanged zeolite in a humid atmosphere to generate new catalytically active sites in the reexchanged zeolite; A method comprising: 9. In the method according to any one of claims 1 to 8, the silylated zeolite is heated at 300 to 500°C in an inert or reducing atmosphere to carry out condensation-polymerization of the silylated surface. A method characterized by promoting. 10. The method of claim 9, wherein the large pore zeolite is a natural or synthetic zeolite having an average pore size of about 7 Å or more. 11. The method according to claim 10, wherein the large-pore zeolite is zeolite Y. 12. The method according to claim 11, by contacting the zeolite with a vaporous or liquid organosilane or an organosilane dissolved in a dry non-reactive organic solvent at a temperature of 20 to 500°C. A method characterized by carrying out silylation. 13 In the method according to claim 12, organic silane is added in a dry non-reactive organic solvent at 0.01%
A method characterized by dissolving at a concentration of 20% by volume. 14 In the method according to claim 13, the organic silane has the following formula SiR _y X _4-y or (R _w X _3-w Si) ₂ Z (wherein R is H or C ₁ to C ₁₀ an alkyl, aryl, alkoxy or aralkyl group, X is halogen, Z is O, NH, substituted amine, or substituted amide, y is 1 to 4, and w is 1 to 3) A method characterized by comprising: 15. The method according to claim 14, wherein the organic silane is hexamethyldisilazane (HMDS) or hexamethyldisiloxane (HMDSO). 16. The method of claim 15, characterized in that the zeolite is combined with a catalytically active hydrogenation component before or after the silylation. 17. The method of claim 16, wherein the catalytically active hydrogenation component is selected from the group consisting of metals of Groups and Groups of the Periodic Table, oxides or sulfides of said metals, and mixtures thereof. A method characterized by: 18. The method of claim 17, wherein the catalytically active hydrogenation component is present in an amount of 0.1 to 2.0% by weight of the dry zeolite. 19. The method of claim 18, wherein the catalytically active hydrogenation component is platinum or palladium.