The way the disproportionation of toluene
(57) Abstract:The invention relates to an improved method for the disproportionation of toluene comprising processing the catalyst is a molecular sieve selected from the group comprising ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-35, preferably ZSM-5, selectivities on paraxylene organosilicon agent and contacting a reaction stream containing toluene, with the specified catalyst at a temperature 350-540oWith the pressure 100-35000 KPa, space velocity of the raw material is 0.1-20 h-1and the molar ratio of hydrogen to hydrocarbon of 0.1-2.0, characterized in that as selectivities on paraxylene organosilicon agent use volatile organosilicon compound selected from the class of siloxanes, silanes or disilanes, and handling of the catalyst specified selectivities agent is carried out by feeding selectivities agent, taken in an amount of 0.1-50 wt.% by weight of toluene, simultaneously with the filing of the reaction stream containing toluene, for up to 300 h to obtain in a single pass product containing at least 90% of paraxylene by weight of the component WITH8when the conversion of toluene at least 15 wt. %. Technical achiev the Cesky acceptable levels of conversion of toluene. 9 C.p. f-crystals, 6 ill., 14 table. The present invention relates to a method for the disproportionation of toluene and, in particular, to a method for the selective disproportionation of toluene to paraxylene.The term "catalysts that are sensitive to the form" describes the unexpected catalytic selectivity in zeolites. The principles underlying the selective form catalysts were seriously studied and discussed, for example, N. Y. Chen, W. E. Garwood and F. G. Dwyer "Shape Selective Catalysis in Jndustrial Applications /Sensitive to the shape of the catalysts, their use in industry", 36: Marcel Dekker, Inc. /1989/. Within the pores of zeolites such reactions of hydrocarbons, as the isomerization of paraffin, the skeletal isomerization of olefins or double bond, oligomerization and disproportionation of aromatics, alkylation reaction or TRANS-alkylation, are defined by spatial difficulties, which depend on the size of the channel. The selectivity of the reagents is observed in cases when part of the raw materials is too large to enter the pores of the zeolites for the reaction; whereas the selectivity of the product occurs when part of the products may not leave the channels of the zeolites. On the distribution of products can also affect the selectivity of the transition is IR, to occur within the pores or cavities of zeolites. Another type of selectivity is determined by the configuration of the diffusion when the sizes of the molecules close to the size of the pores of the zeolite. Small changes in the size of the molecules or pores of the zeolite can lead to a serious change of diffusion, which will lead to a different distribution of products. This type of selectivity in the form of catalysts demonstrate, for example, in the process of selective disproportionation of toluene paraxylene.Paraxylene is a valuable commercial product, suitable for polyester fibers. Catalytic obtain paraxylene attracted much attention from scholars, and has been proposed many methods for improving the catalytic para-selectivity.Synthesis of paraxylene are usually due to the methylation of toluene in the presence of a suitable catalyst. Examples include the reaction of toluene with methanol as described by Chen et al., J. Amer. Chem. Sec. 1979, 101, 6783, and the disproportionation of toluene described Pines in "The Chemistry of Catalytic Hydrocarbon Conversions", Academic Press, N. Y., 1981, p. 72. Such methods typically produce a mixture containing paraxylene, orthoxylene and betaxolol. Depending on pair with the industry, the quantities actually turned in xylene, also depends on the catalyst and reaction conditions.The equilibrium reaction of disproportionation of toluene to xylene and benzene proceeds as follows (see end of description)
< / BR>One of the famous ways to enhance the para-selectivity of zeolite catalysts is a modification of the catalyst by treatment with "selectivities agent". Have been proposed methods of modification, where the catalyst for change through treatment before use, obtaining the coverage is silicon dioxide. So, for example, U.S. patents 4477583 and 4127616 reveal the ways in which carry out the contacting of the catalyst at ambient conditions with such a modifier compound, as fenilmetiliden in a hydrocarbon solvent, or in aqueous emulsion, followed by calcining. Such procedures modification was successful to obtain a para-selectivity of up to about 90%, but only on expensive, commercially unacceptable toluene conversion of about 10%, which led to the release of no more than about 9%, i.e., 10% x 90%. Such methods also lead to obtaining significant quantities of ortho-xylene and meta-xylene, and therefore require doregos what I paraxylene from other isomers. Other isomers of xylene usually recyclist that requires isomerization of xylene for additional conversion recyclebank of xylene isomers in equilibrium mixture of xylenes containing paraxylene.Experts believe that the cost of the separation process is proportional to the degree necessary separation. Therefore, it is possible to significantly save money, increasing the selectivity for prisonera, while maintaining commercially acceptable levels of conversion.Therefore, the aim of the present invention is to create a regioselective process to obtain a paraxylene from toluene, while maintaining commercially acceptable levels of conversion of toluene. Accordingly, the present invention is to a process for the disproportionation of toluene, which includes the implementation of contacting the raw material stream consisting of toluene, the catalyst is a molecular sieve to obtain a product in one passage containing at least about 90% by weight paraxylene from C8the component with the conversion of toluene, at least about 15 wt.%.The catalyst is a molecular sieve used in the method of the present invention preferably have an initial index with an intermediate pore size, as ZSM-5, ZSM-11, ZSM-22, ZSM-23 or ZSM-35, more preferably ZSM-5. The value for the catalyst, preferably more than 100, for example, 150-200, and the ratio of silica/alumina of less than 100, preferably 20-80. The alpha value of the catalyst can be improved by treating the catalyst with nitric acid or mild steam, which are disclosed in U.S. patent 4326994.Number alpha is an approximate indication of the catalytic cracking activity of the catalyst compared to a standard catalyst and it gives the relative rate constant / speed conversion of normal hexane per volume of catalyst per unit time. It is based on the activity of amorphous cracking catalyst silica-alumina, taken as alpha 1 /constant speed = 0,016 sec-1/. Alpha test is described in U.S. patent 3354078 and in the Journal of Catalysis, Vol 4, p. 522-529 /August 1965/, Vol. 6, p. 278 /1966/ and Vol. 61, p. 395 /1980/. It is noted that the characteristic rate constants for many reactions with acid catalysts is proportional to the alpha index for a particular crystalline silicate catalysts /see "The Active Site of Acidic Aluminosil cate Catalysis", Nature, Vol. 309, N 5959 June 14, 1984/. Used in the experiment conditions include constant is zeemote and the method of its determination is described in U.S. patent N 4016218.The catalyst is a molecular sieve used in the method of the present invention can be used in combination with the material of the carrier or binder, for example, a porous inorganic oxide carrier or a clay binder. The preferred binder is mainly silicon dioxide. Other limitiruyuschie examples of binder materials include aluminum oxide, zirconium dioxide, magnesium oxide, thorium dioxide, titanium dioxide, dioxide, boron and combinations thereof, usually in the form of dried gels inorganic oxides or gelatinousness precipitation. Suitable materials clays include, for example, bentonite and diatomaceous earth. The relative content of suitable crystalline molecular sieves to the full composition of the catalyst and a binder or carrier can be 30-90 wt.%, and preferably 50-80 wt.% by weight of the composition. The composition may be in the form of an extrudate, pellets or fluorinated microspheres.In one embodiment of the present invention the catalyst is a molecular sieve have the necessary paraxially selectivity and degree of conversion of toluene due to pre-treatment ex - 1 and selectivities agent /hereinafter referred to as pre-selectivities the surface of the catalyst in any suitable way. For example, the silicon-containing compound can be dissolved in a solvent, mixed with a catalyst, and then dried, used silicon compound can be in the form of a solution, a liquid or a gas under the conditions of contact with the zeolite. Examples of methods of application of silicon on the surface of the zeolite described in U.S. patent 4090981, 4465886 and 4477583.After applying the silicon-containing compounds in the process of pre-selectivity, catalyst, preferably calicivirus. For example, the catalyst can be calcinate in oxygen-containing atmosphere, preferably air, at a speed of 0.2-5oC / minute to a temperature above 300oC, but below the temperature at which deteriorate the crystallinity of the zeolite. Typically, such temperature is below 600oC. the Preferred temperature calcination are in the approximate range 350-550oC. the Product is maintained at a temperature of calcination usually within 1-24 hours.In another embodiment of the invention the catalyst is a molecular sieve injected with necessary paraxially selectivity and degree of conversion of toluene due to in situ processing selectivities agent /hereinafter referred to as "trim-selectiveserotonin, at least during the initial stages of the reaction. Phase trim-selectively preferably lasts 50-300 hours, more preferably less than 170 hours. Selectivities agent serves in an amount of from 0.1 to 50%, preferably from 0.1 to 20% by weight by weight of toluene.Trim-selectivity agent, preferably, is a volatile organosilicon compound and the reaction conditions during the beginning phase reactions usually are temperatures of from 100 to 600oC, preferably from 300 to 500oC; pressure from 100 to 140000 KPa /0-200 km psig/, preferably, from 200 to 5600 KPa /16-800 psi/; molar ratio of hydrogen to hydrocarbons of from 0 /that is, hydrogen is absent/ to 10, preferably from 1 to 4, when the weight hourly rate /WHSY/ from 0.1 to 100, preferably from 0.1 to 10. After thermolysis silicon coating is deposited on the surface of the zeolite, reducing or eliminating surface activity, and increasing selectivity for the form.In another embodiment of the invention, the catalyst is subjected to as pre-selectively and trim-selectively.The silicon compounds used for pre-selectively and/or trim-selectivity may contain polysiloxane, including silicones, siloxane and the silane of the present invention, can be characterized by the following General formula:
< / BR>where R1represents hydrogen, fluorine, hydroxyl, alkyl, aralkyl, alkaryl or foralkyl. Hydrocarbon substituents typically contain 1 to 10 carbon atoms and preferably are methyl or ethyl groups. R2choose from the same group, and R1and n is an integer at least 2 and usually in the range from 2 to 1000. The molecular weight used siloxane compounds is usually in the range from 80 to 20,000, preferably from 150 to 10,000. Representative siloxane compounds include dimethylsiloxane, diethylsiloxane, diethylsiloxane, phenilmethylsulfoxide, methylhydrosiloxane, emilydickinson, phenylhydroxylamine, metiletilketoksim, fenilatilamin, diphenylsiloxane, methyltrichlorosilane, ethyltrichlorosilane, tetrachlorodibenzodioxin, tetrachlorosalicylanilide, tetrachlorodibenzodioxin, tetrachlorodibenzodioxin, methylvinylsiloxane and ethylvanillin. Siloxane compounds do not necessarily have to be linear, they may be cyclic, for example, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, hexaphenylcyclotrisiloxane and activeline groups.Suitable siloxanes or polysiloxanes include, as limitiruesh examples, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, octamethyltrisiloxane, decamethylpentasiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, hexaphenylcyclotrisiloxane and Octafinal-cyclotetrasiloxane.Suitable silanes, disilane or alkoxysilane include organic substituted silanes of the General formula:
< / BR>where R represents a reactive group, as hydrogen, alkoxy, halogen, carboxy, amino, ndimethylacetamide, trialkylsilyl. R1, R2and R3can be the same as R or can be an organic radical which may include alkyl containing from 1 to 40 carbon atoms, alkyl - or aryl-carboxylic acids, in which the organic portion of the alkyl contains from 1 to 30 carbon atoms, and the aryl group contains from 6 to 24 carbon atoms, aryl groups containing from 6 to 24 carbon atoms, which in turn can be substituted alcylaryl and arylalkyl groups containing from 7 to 30 carbon atoms. Preferably, the alkyl group of alkylsilane contain from 1 to 4 atoms of plastics technology: turning & the exporting examples dimethylphenylsilane, phenyltrimethylsilane, triethylsilane and hexamethyldisilane. Suitable alkoxysilanes are those in which there is at least one silicon-hydrogen bond.It is believed that the advantages of the present invention are achieved through the creation of acid sites on the external surfaces of the catalyst, is practically inaccessible to the reactants, at higher iskrivlennoi the catalyst surface. The acid sites existing on the external surface of the catalyst, it is believed, will someresult paraxylene, leaving the pores of the catalyst back to the equilibrium state, and the other two isomers due to this, reduce the amount of paraxylene to only about 24%. Lowering the ability of these acid sites display paraxylene from the pores of the catalyst, it is possible to achieve a relatively high level of paraxylene. Believe that selectivities agents of the present invention block or in some other way make these external acid sites available for paraxylene due to the chemical modification of these centers.Preferably, the kinetic diameter selectivities agent was larger than the diameter of the pores of the zeolite in order to avoid reducing the internal activity katal target yield of paraxylene, if a silicon compound is used as a trim-selectivities agent.Disclosed here is a method substantially increases the efficiency of obtaining paraxylene. So for example, you can achieve purity paraxylene more than 90 wt. %, preferably at least 95% by weight, and most preferably at least 97% by weight, based on all of C8products, conversion of toluene over 15%, preferably at least 25%, and most preferably at least 50 wt.%. Moreover, the contents orthoxylene isomer can be reduced to not more than about 0.5% of the total content of xylene, while the content of the meta-isomer can be reduced to less than about 5% of the total content of xylene. In addition, if the reaction system is properly handled, for example, the molecular sieve besieged platinum, the presence of ethylbenzene can be reduced significantly, for example, to less than about 2% C8product.Raw materials which are used in the method of the present invention, preferably contains from 50 to 100%, more preferably at least 80% by weight of toluene. Other compounds, such as benzene, xylenes and trimethylbenzene may also be present AI so to minimize the amount of moisture entering the reaction zone. There are countless ways of drying the toluene entering the process of the present invention. These methods include pre-transmission through any suitable desiccant, such as silica gel, activated alumina, molecular sieve, or any other suitable substance or the use of dehumidifiers with liquid.Operating conditions for the process of disproportionation of toluene present invention include a temperature 350-540oC, preferably more than 400oC, pressure 100-35000 KPa /from atmospheric to 5000 psi/ preferably 800-7000 KPa /100-1000 psi/, WHSY 0.1 to 20, preferably 2-4, and the molar ratio of hydrogen to hydrocarbon of 0.1-20, preferably 2-4. This way you can maintain in the reactor with stationary and fluorinated layer, reaching, in each case in this way the advantages.The exit stream are separated and distilled to remove the desired product, i.e., paraxylene, plus other products. Unreacted reagent, i.e. toluene, preferably, recyclist for further reaction. A valuable by-product is benzene.
8factions often rises to 3-4%. Such levels of ethylbenzene unacceptable for paraxylene polymer purity, as if the ethylbenzene in C8the product is not removed, it reduces the quality of the fiber that you get from the target paraxylene. Accordingly, the content of ethylbenzene should be low. Industrial requirements of the content of ethylbenzene in the product C8should be less than 0.3%. Ethylbenzene can be substantially removed by isomerization or in the process of superfractionation. Remove ethylbenzene conventional isomerization in the practice of the present invention would be impractical because the flow of xylene, which contains more than 90% paraxylene, have undergone a competitive isomerization to equilibrium xylenes, which would reduce the amount of paraxylene in xylene stream to about 24%. Moreover, it is known that an alternative method of removal of ethylbenzene by superfractionation extremely expensive.
product ethylbenzene advantageously reduced with the introduction of the function of the hydrogenation-dehydrogenation in the catalyst by the addition of such a metal link, as platinum. Although the preferred metal is platinum, you can use other metals, such as palladium, Nickel, copper, cobalt, molybdenum, rhodium, ruthenium, silver, gold, mercury, osmium, iron, zinc, cadmium and mixtures thereof. The metal can be added to the catalyst due to cation exchange in the amount of 0.01-2%, typically about 0.5%. The metal must be able to enter the pores of the catalyst to withstand subsequent stage of calcination. For example, the catalyst modified with platinum, can be obtained by first adding to the catalyst solution of ammonium nitrate for the conversion of the catalyst in the ammonia form, and then an aqueous solution of nitrate of tetraamine platinum (II) to improve the activity. Then the catalyst was filtered, washed with water and calicivirus at a temperature of 250-500oC.Hereinafter the present invention will be described in more detail with reference to examples and the corresponding drawings, in which:
Fig. 1 is a graph comparing the para-selectivity of xylene and conversion of toluene depending on siloxane trim-selectavision ZSM-5 catalyst in the presence of hydrogen /example 1/ or nitrogen, as a function of time in the stream.Fig. 2 represents graylee low temperatures, used in example 2.In Fig. 3 also shows a graph similar to Fig. 1, which shows the results obtained without filing a joint hydrogen /example 3/.Fig. 4 is a plot of conversion of the paraxylene and toluene from the time stream.Fig. 5 is para-selectivity and speed of conversion to zeolite, which was previously selectavision with 10% SiO2and
Fig. 6 is para-selectivity and speed of conversion to zeolite, which was pre-selectavision with 5% SiO2.Example 1
Disproportionation of toluene is carried out in a reactor with a fixed bed using 2 g of silicon dioxide that is associated with the catalyst HZSM-5 with respect to silicon dioxide/aluminum oxide 26, a crystal size of 0.1 microns, the amount of alpha 731. Fed to the reactor the material is toluene with 1% siloxane compounds with respect to phenilmethylsulfoxide to dimethylsiloxane 1:1. Working conditions: WHSY 4,0, 480oC, 3550 KPa /500 psi/ and the ratio of hydrogen/hydrocarbon of about 2.In table 1 (see the end of the description) presents the conversion of toluene and selectivity for paraxylene, as a function of time in the stream during and palestinethe paraxylene from the initial 22% to over 90%. When working in the stream for 174 hours of raw materials replace 100% toluene, i.e. stop simultaneous delivery of siloxane materials. After a week of work in test mode, the conversion of toluene remains constant at 25% and the selectivity for paraxylene remains constant at 91%.The above results are also illustrated in Fig. 1, which also includes the results of selectivity in the presence of nitrogen rather than hydrogen. In the presence of nitrogen, the catalyst is rapidly deactivated and the conversion quickly down to zero.Example 2.Repeat the process for the disproportionation of toluene of example 1 when WHSY 4,0, 446oC, 3550 KPa /500 psi/ and the ratio of hydrogen/hydrocarbon = 2. In table 2 (see end of description) summarizes the conversion of toluene and selectivity for paraxylene depending on the time in the stream.Siloxane trim-selectivity increases the selectivity for paraxylene from 24% /thermodynamic value to a much higher value, as 97% at 25% conversion of toluene. If you stop filing siloxane, selectivity for paraxylene and conversion of toluene remain unchanged at 97% and 25%, respectively. The results obtained are shown in Fig. 2./ and the ratio of hydrogen/hydrocarbon = 0. In table 3 (see below) and in Fig. 3 summarizes the conversion of toluene and selectivity of paraxylene as a function of time in the stream. It should be noted that conversion rate drops almost to 0 after 184 hours in the stream as opposed to the process, which is conducted in hydrogen, when after 184 hours on stream conversion stabilized at 25%.Example 4
Carry out the disproportionation of toluene over SiO2-HZSM-5 using a 1% octamethylcyclotetrasiloxane in toluene /raw/ as trim-selectivities agent. Working conditions: 446oC, 3550 KPa /500 psig/, 4,0 WHSY and H2/HC=2. The results are shown in table 4 (see end of description)
Carry out the disproportionation of toluene with trim-selectivities according to the method of example 4 using hexamethyldisiloxane /GMDC/. The results obtained are presented in table 5 (see below) and in Fig. 4.In Fig. 4 shows a high selectivity for paraxylene and conversion of toluene over 350 hours in the stream. The conversion of toluene remains at about 18 - 20% with a selectivity of paraxylene 99% for a long period of time. Filing HMDS /GMDC/ stop after about 50 hours.Examples of 6 - 14
Repeat the process p is KPa /500 psig/, WHSY 4.0 and H2/HC=2. Obtained after 24 hours the results are shown in table 6 (see the end of the description).Examples 15 - 19
Trim-selectively by way of examples 4 and 5 is carried out with the silanes listed in table 7. Working conditions: 446oC, 3550 KPa /500 psig/, 4,0 WHSY and H2/HC=2. The results are shown in table 7.a/ continued selectively after 24 hours leads to selectivity for paraxylene about 90%.Examples 20-24
In order to compare the compounds listed in table 8, were tested according to the method of examples 6-19, and the results are presented in table 8 (see the end of the description).Example 25
Silicon dioxide pre-selectavision catalyst ZSM prepared by adding to 5.00 g of HZSM-5 to 1.26 g of phenylethanolamine dissolved in 40 cm3hexane. The solvent is distilled off, and the catalyst calicivirus air with a speed of 1oC/min to 538oC, then 6 hours at 538oC. Pre-selectavision the catalyst containing nominally 10% added silica.Trim-selectively 10% SiO2-HZSM-5 silicone is carried out at a temperature of 446oC, 3550 KPa /500 psig/, 4, DWHSY and the ratio of hydrogen/hydrocarbon = 2. In table 9 and in Fig. 5 LASS="ptx2">Trim-selectivity of siloxane significantly increases the selectivity for paraxylene from 33% to 98% within 28 hours in the stream. Then the raw material is replaced with 100% toluene. After the next ten hours, the selectivity increases to 99% when the conversion of 16%. To further enhance the conversion temperature is increased to 457oC, and shortly thereafter to 468oC. the Conversion increased to 21%, then slightly reduced to 20% over the next 80 hours. Selectivity for paraxylene increases to 99.2 to 99.6% for the same 80 hours.Comparison of the catalyst of example 1 HZSM-5 and 10% O2-HZSM-5 /pre-selectavision/ catalyst of example 25 demonstrates a significantly higher rate of selectivity for the second. For pre-selectavision HZSM-5 selectivity for paraxylene 89% is achieved after only 10 hours on stream /17 times faster than 170 hours for the original HZSM-5/. In addition, the time required to achieve optimal pair-selectively, 1 day for pre-selectavision HZSM-5 compared with 1 week for HZSM-5, is smaller, despite a higher temperature for HZSM-5 /480oC compared with 446oC/.The entire expense of fenilmetiliden amounted to 6.80 g of silicone on the g HZSM-5 and 1.42 g of silicone on the HZSM-5 requires nearly five times /4,79/ less siloxane, than in the case of continuous-selectavision catalyst.Example 26
Repeat example 25, but with pre-selectavision catalyst containing only 5% of the added silica. In table 10 (see the end of the description), and Fig. 6 shows the conversion of toluene and selectivity for paraxylene to 5% SiO2-HZSM-5, as a function of time in the stream.Trim-selectivity silicone significantly increases the selectivity of paraxylene from 25% to 98% after 26 hours in the stream. Compared to 10% SiO2-HZSM-5, 5% SiO2the catalyst shows high constant conversion after one day time selectively. Then the raw material is changed to 100% toluene. After the next 6 hours selectivity increases to 99% when the conversion of 24%, the temperature is increased to 468oC, WHSY reduced to 3. The conversion increases to 27%, then decreases and remains constant at 21% for 6 days /146 hours/. Accordingly, the selectivity for paraxylene initially remains unchanged at 99%, then gradually increases and remains constant at 99,6%-99,9% for 6 days, when the experience was over.Example 27
0,05% Pt-10% SiO2-HZSM-5 catalyst prepared by adding 2.50 g of 10% SiO2-HZSM-5 obtained in primini /II/ in approximately 0.5 cm3water. After maturation during the night, calicivirus air with a speed of 5oC/min to 350oC, then 3 hours at 350oC.Disproportionation of toluene are over 2 g of the obtained catalyst at 446oC, 3550 KPa /500 psig/, 4 WHSY and molar ratio hydrogen/hydrocarbons of 2.0. In table 11 (see below) shows the distribution of the product in comparison with modified silica HZSM-5 without Pt from example 25, which was tested in the same operating conditions. When a similar conversion of toluene amount of the resulting ethylbenzene is reduced to nearly 12 times when using a Pt-catalyst. The number of unwanted C+9aromatic products also decreases almost in 2 times.Example 28
The catalyst of example 27 is treated in situ with 1% solution of phenylethanolamine in toluene at 446oC, 3550 KPa /500 psig/, 4 WHSY and molar ratio hydrogen/hydrocarbons of 2.0. After 32 hours in the flow of raw materials change in 100% toluene. In table 12 (see below) presents the distribution of the product in comparison with a catalyst that did not contain platinum and was treated with siloxane HZSM-5, which is tested in the same operating conditions.At the same coniuncti on paraxylene remains very high when to 98.4-98.7 per cent. Unwanted C+9aromatic product is also decreased almost three times.The results of examples 29 to 31, are presented in table 13 indicate that the addition of platinum to the catalyst, molecular sieves decreases the content of ethylbenzene in the stream of the final product.Example 29
Trim-selectively silicone 10% SiO2-HZSM-5 is conducted using a 1% phenilmethylsulfoxide in raw toluene at 446oC, 3550 KPa /500 psig/, 4,0 WHSY and the ratio of hydrogen/hydrocarbon = 2. After 31 hours in the flow of raw materials change in 100% toluene. After 52 hours on stream the temperature was raised to 468oC, and after 165 hours WHSY reduce to 3.0. Received within 39 days of data are presented in column 1 of table 13.Example 30
Selectively siloxane 0,025% Pt SiO2-HZSM-5 is conducted using a 1% phenilmethylsulfoxide in raw toluene at 446oC, 3550 KPa /500 psig/, 4,0 WHSY in a molar ratio hydrogen/hydrocarbon = 2. After 56 hours in the flow of raw materials change in 100% toluene. After 73 hours on stream the temperature was raised to 468oC. the Results obtained for 7 days in the stream, are presented in table 13, column 2.Example 31
Selectively siloxane treated with nitric acid, soteria psig/, 4,0 WHSY and molar ratio hydrogen/hydrocarbon = 2. After 27 hours in the flow of raw materials to replace 100% toluene. During the experience change temperature, WHSY and the ratio of hydrogen/hydrocarbon. The results of 13 days in the stream are presented in column 3 of table 13.Examples 29-31 show that the content of ethylbenzene in the reaction products of the present invention can be reduced through the use of catalytic molecular sieves with this function hydrogenation/dehydrogenation, like platinum, is included in the catalytic molecular sieve. The amount of ethylbenzene in the product flow, preferably, is at a commercially acceptable level, not more than 0.3%, and most preferably not more than about 0.2%.As mentioned previously, the present invention successfully get the product stream of high purity paraxylene relative to other C8products. In table 14 (see end of description) presents the relative proportions of paraxylene to different combinations of other products. 1. The way the disproportionation of toluene comprising processing the catalyst is a molecular sieve selected from the group comprising ZSM - 5, ZSM - 11, ZSM - 22, ZSM - 23 and ZSM - 35, preferably ZSM - 5, selectivity the specified catalyst at a temperature of 350 540oC, a pressure of 100 - 35000 KPa, space velocity of the raw material is 0.1 - 20 h-1and the molar ratio of hydrogen to hydrocarbon of 0.1 to 20, characterized in that as selectivities on paraxylene organosilicon agent use volatile organosilicon compound selected from the class of siloxanes, silanes or disilanes, and handling of the catalyst specified selectivities agent is carried out by feeding selectivities agent, taken in an amount of 0.1 - 50 wt.% by weight of toluene, simultaneously with the filing of the reaction stream containing toluene, for up to 300 h to obtain in a single pass product containing at least 90% of paraxylene by weight of component C8when the conversion of toluene at least 15 wt.%.2. The method according to p. 1, characterized in that the reaction stream comprises at least 80 wt.% of toluene.3. The method according to PP. 1 and 2, characterized in that the used catalyst HZSM-5, pretreated specified selectivities on paraxylene agent.4. The method according to P3, characterized in that use the specified catalyst containing from 0.01 to 2 wt.% hydrogenating-dehydrating component.5. The method according to p. 4, otlichayetsa.6. The method according to p. 1, characterized in that the contact will receive xylene, containing not more than 0.5 wt.% orthoxylene and not more than 5 wt.% metaxalona.7. The method according to p. 1, wherein at least 25 wt.% toluene is converted into xylene.8. The method according to p. 1, wherein at least 30 wt.% toluene is converted into xylene.9. The method according to p. 1, characterized in that obtained in a single pass product contains at least 95 wt.% paraxylene per component C8.10. The method according to p. 1, characterized in that obtained in a single pass product contains at least 97 wt.% paraxylene per component C8.
FIELD: petrochemical processes.
SUBSTANCE: simultaneous dehydrogenation of mixture containing alkyl and alkylaromatic hydrocarbons is followed by separating thus obtained dehydrogenated alkyl hydrocarbon and recycling it to alkylation unit. Dehydrogenation reactor-regenerator employs C2-C5-alkyl hydrocarbon as catalyst-transportation carrying medium.
EFFECT: increased process flexibility and extended choice of catalysts.
FIELD: organic synthesis catalysts.
SUBSTANCE: invention relates to catalyst for aromatization of alkanes, to a method of preparation thereof, and to aromatization of alkanes having from two to six carbon atoms in the molecule. Hydrocarbon aromatization method consists in that (a) C2-C6-alkane is brought into contact with at least one catalyst containing platinum supported by aluminum/silicon/germanium zeolite; and (b) aromatization product is isolated. Synthesis of above catalyst comprises following steps: (a) providing aluminum/silicon/germanium zeolite; (b) depositing platinum onto zeolite; (c) calcining zeolite. Hydrocarbon aromatization catalyst contains microporous aluminum/silicon/germanium zeolite and platinum deposited thereon. Invention further describes a method for preliminary treatment of hydrocarbon aromatization catalyst comprising following steps: (a) providing aluminum/silicon/germanium zeolite whereon platinum is deposited; (b) treating zeolite with hydrogen; (c) treating zeolite with sulfur compound; and (d) retreating zeolite with hydrogen.
EFFECT: increased and stabilized catalyst activity.
26 cl, 1 dwg, 5 tbl, 4 cl
SUBSTANCE: zeolite catalyst for process of conversion of straight-run gasoline to high-octane number component is described. The said catalyst contains high-silica zeolite with SiO2/Al2O3=60 and residual content of Na2О of 0.02 wt.% maximum, metal-modified, Pt, Ni, Zn or Fe metals being in nanopowder form. Content of the said metals in the catalyst is 1.5 wt.% maximum. Method to manufacture zeolite catalyst for conversion of straight-run gasoline to high-octane number component is described. The said method implies metal modification of zeolite, Pt, Ni, Zn or Fe metals being added to zeolite as nanopowders, produced by electric explosion of metal wire in argon, by dry pebble mixing in air at room temperature. Method to convert straight-run gasoline using the said catalyst is also described.
EFFECT: increase in catalyst activity and gasoline octane number, accompanied by increase in yield.
4 cl, 3 tbl, 4 ex
SUBSTANCE: method involves hydrocarbon transformation in a reactor in the presence of modified catalyst containing, mass %: 53.0-60.0 of ZSM-5 high-silica zeolite with the ratio of SiO2/Al2O3=39, 34.0-38.0 of Al2O3, 2.0-5.0 of B2O3, 1.0-5.0 of Zn, 0.0-5.0 of W, 0.0-3.0 of La, 0.0-3.0 of Ti at 300÷700°C, including separation of liquid and solid transformation products, followed by burning oxidation of gaseous products and addition of the obtained mix of carbon dioxide and water vapour to the source hydrocarbons at the rate of 2.0÷20.0 mass %. Before the raw material intake the reaction system is flushed by an inert gas (nitrogen), starting from 300°C and to the transformation temperature. Hydrocarbons used are alkanes, olefins or alkane olefin mixes C2-C15 without preliminary separation into fractions. Gaseous transformation products undergo burning and complete oxidation in the presence of an oxidation catalyst of vanadium/molybdenum contact piece, V2O5/MoO3. To sustain continuous process two identical reactors are used, where the catalyst is transformed and recovered in turns.
EFFECT: longer working transformation cycle due to the continuous process scheme; higher yearly output of aromatic hydrocarbons; reduced energy capacity and improved ecology of the process.
SUBSTANCE: invention describes zeolite-containing catalyst for transformation of aliphatic hydrocarbons C2-C12 to a mix of aromatic hydrocarbons or high-octane gasoline component containing zeolite ZSM-5 with silicate module SiO2/Al2O3=60-80 mol/mol and 0.02-0.05 wt % of residual sodium oxide content, zeolite structural element, promoter and binding component, with zirconium or zirconium and nickel oxides as zeolite structural component, and zinc oxide as promoter, at the following component ratio (wt %): zeolite 65.00-80.00; ZrO2 1.59-4.00; NiO 0-1.00; ZnO 0-5.00; Na2O 0.02-0.05, the rest being binding component. Also, a method for obtaining zeolite-containing catalyst is described, which involves mixing reagents, hydrothermal synthesis, flushing, drying and calcinations of sediment. The reaction mix of water solutions of aluminum, zirconium and nickel salts, sodium hydroxide, silicagel and/or aqueous silicate acid, inoculating zeolite crystals with ZSM-5 structure in Na or H-form, and structure-former, such as n-butanol, is placed in an autoclave, where hydrothermal synthesis is performed at 160-190°C for 10-20 hours with continuous stirring; the hydrothermal synthesis over, Na-form pulp of the zeolite is filtered; the obtained sediment is flushed with domestic water and transferred to salt ion exchange by processing by water ammonium chloride solution with heating and stirring of the pulp; the pulp obtained from salt ion exchange is filtered and flushed with demineralised water with residual sodium oxide content of 0.02-0.05 wt % on the basis of dried and calcinated product; flushed sediment of ammonium zeolite form proceeds to zinc promoter introduction and preparation of catalyst mass by mixing of ammonium zeolite form modified by zinc and active aluminum hydroxide; obtained catalyst mass is extruded and granulated; the granules are dried at 100-110°C and calcinated at 550-650°C; calcinated granules of zeolite-containing catalyst are sorted, ready fraction of zeolite-containing catalyst is separated, while the granule fraction under 2.5 mm is milled into homogenous powder and returned to the stage of catalyst mass preparation. The invention also describes method of transformation of aliphatic hydrocarbons to high-octane gasoline component or a mix of aromatic hydrocarbons (variants), involving heating and passing raw material (gasoline oil fraction direct sublimation vapours or gas mix of saturated C2-C4 hydrocarbons) through stationary layer of the aforesaid catalyst.
EFFECT: reduced number of components and synthesis stages of zeolite-containing catalyst; increased transformation degree of raw material; improved quality and yield of target products with the said catalyst.
4 cl, 8 tbl, 12 ex
SUBSTANCE: alkylbenzol with structure R1R2CH(Ph) is obtained from alkylphenyl alcohol with structure R1R2C(Ph)OH. Method includes following stages: (a) supply of initial flow, containing alkylphenyl alcohol with structure R1R2C(Ph)OH, into reactor with catalytic distillation zone; (b) simultaneously in reactor: (i) contacting of initial flow, containing R1R2C(Ph)OH, with hydrogen in catalytic distillation zone in order to convert R1R2C(Ph)OH into R1R2CH(Ph) and to form reaction mixture and (ii) separation of R1R2CH(Ph) from reaction mixture by fraction distillation in order to obtain higher than catalytic distillation zone, flow, which contains R1R2CH(Ph) with lower concentration of R1R2C(Ph)OH in comparison to initial reactor flow in position higher than catalytic reaction zone; R1 and R2 each represent hydrogen or hydrocarbon group with 1-10 carbon atoms and one of R1 and R2 is not hydrogen.
EFFECT: more pure alkylbenzol with smaller amount of undesirable by-products and using smaller number of stages.
6 cl, 5 tbl, 1 dwg
SUBSTANCE: invention refers to the method for preparation of aromatic hydrocarbons accompanied with simultaneous obtaining of hydrogen, methanol, motor oils and fresh water from the unstable hydrocarbon gas condensate obtained from gas condensate and oil fields including if necessary its desulphurisation, following obtaining of synthesis gas by one-stage oxidising with air oxygen, its conversion to methanol, following catalytic conversion of methanol to motor oils, separation of the water formed on all process stages, evaporation of the hydrocarbons residues including methanol and fatty hydrocarbons from the water (united and formed on all process stages), water bioremediation and mineralisation. The initial hydrocarbon gas is unstable hydrocarbon gas condensate without preliminary separation of methane and ethane from propane and butane, the said initial gas before its conversion to synthesis gas undergoes the catalytic aromatisation during heating. Then the obtained aromatic hydrocarbon and hydrogen are separated, hydrogen is at least partially used for synthesis gas obtaining in order to change the ratio H2:CO 1.8-2.3:1), and if necessary it is partially used on the stage of desulphurisation with synthesis gas obtaining from hydrocarbon gases (unreacted and formed on the aromatisation stage). The invention refers also to the device for implementation of the method described above.
EFFECT: increasing of the processing of the efficiency of unstable hydrocarbon gas condensate with enhanced obtaining of target products, to make the process more environmentally safe, to increase the quantity and quality of the obtained fresh water.
2 cl, 5 ex, 1 dwg
SUBSTANCE: method of hydrocarbon aromatisation includes: a) contacting of alkane containing from 2 to 6 carbon atom in molecule with at least one catalyst consisting virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen and b) separation of aromatic products. The preparation method for platinum-gallium zeolite catalyst used for hydrocarbon aromatisation is described, it includes: preparation of gallium zeolite containing silicon and gallium; precipitation of the platinum to said zeolite; and c) zeolite calcination. In the said method the said gallium zeolite catalyst consists virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen. The platinum- gallium zeolite catalyst for hydrocarbon aromatisation containing: a) gallium-silicon zeolite and b) platinum precipitated to gallium-silicon zeolite is also described. In the said method the said platinum-gallium zeolite catalyst consists virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen.
EFFECT: enhancing of the catalyst selectivity in transforming of lower alkanes to aromatic hydrocarbons.
30 cl, 3 dwg, 4 tbl, 2 ex