MXPA01002974A - Improved epoxidation process - Google Patents

Abstract

The selectivity of an olefin epoxidation process catalyzed by a titanium-containing zeolite is improved by performing the epoxidation in the presence of a non-ionic tertiary amine or tertiary amine oxide additive. For example, when hydrogen peroxide is reacted with propylene in the presence of TS-1 titanium silicalite to form propylene oxide, non-selective ring-opening reactions of the propylene oxide are suppressed when low concentrations of 2,6-lutidine or other substituted pyridines are added to the hydrogen peroxide feed.

Description

IMPROVED EPOXIDATION PROCESS FIELD OF THE INVENTION This invention relates to methods by means of which the selectivity of an olefin epoxidation reaction can be improved. In particular, the invention pertains to an epoxidation process wherein a titanium containing zeolite is used in the presence of a hydrogen peroxide and low concentrations of a tertiary amine or tertiary amine oxide such as a pyridine derivative to catalyze the formation of the epoxide corresponding to the starting olefin while minimizing the production of annular aperture products derived from the epoxide.

BACKGROUND OF THE INVENTION It is well known that the epoxidation of olefinic compounds with hydrogen peroxide can be efficiently catalyzed by certain synthetic zeolites containing titanium atoms (see, for example, US Patent No. 4,833,260). Since the selectivity for the desired epoxide is generally high, the U.S. Patent. No. 4,824,976 proposes that the non-selective ring-opening reactions that take place when the epoxidation is carried out in a protic medium such as water or alcohol can be suppressed by treating the catalyst before the reaction or during the reaction with a suitable acid neutralizing agent. . It is said that the neutralizing agent neutralizes the acid groups on the surface of the catalyst, which tends to promote the formation of by-products. The neutralization, according to the patent, can be carried out with water-soluble basic substances chosen from highly ionized base substances such as NaOH and KOH and weak bases such as NH 4 OH, Na 2 CO 3, NaHCO 3, Na 2 HPO 4 and analogous lithium salts and potassium including K2CO3, Li2CO3, KHCO3, LiHCO3 and K2HPO4¡ alkaline and / or alkaline earth salts of carboxylic acids having from 1 to 10 carbon atoms and alkali and / or alkaline earth alcoholates having from 1 to 10 carbon atoms. carbon. More recently, as described in US Patent Nos. 5,646,314, and 5,675,026 it has been found that the presence of certain non-basic salts (ie, neutral or acidic) such as lithium chloride, sodium sulfate, lithium nitrate, Magnesium acetate and ammonium acetate also improve the selectivity of an epoxidation catalyzed by a titanium-containing zeolite. In the aforementioned patents, however, all substances are said to be ionic in character to be effective in improving the production of epoxide. That is, the selectivity enhancement additives must be capable of dissociation in cationic and anionic species when dissolved in water. There is no teaching or suggestion that none of the nonionic compounds would be able to provide similar benefits when presented in an olefin epoxidation system catalyzed by a titanium containing zeolite.

BRIEF DESCRIPTION OF THE INVENTION We have now unexpectedly discovered that by carrying out a catalyzed epoxidation of titanium silicalite in the presence of low concentrations of a tertiary amine and / or tertiary amine oxide, the selectivity to epoxidase can be significantly improved. In several cases, no harmful effect on the rate of conversion of hydrogen peroxide is observed. This result was surprising in view of the belief in the subject, as evidenced by U.S. Patent Nos. 4,824,976 and 5,675,026, that only ionic species would effectively improve epoxide selectivity. This invention provides an epoxidation method of an olefin comprising contacting said olefin when the hydrogen peroxide in a reaction zone in the presence of a zeolite catalyst containing titanium and an amount of a tertiary amine or oxide thereof is effective to improve the selectivity to epoxidate.

DETAILED DESCRIPTION OF THE INVENTION The hydrogen peroxide (H2O2) used as the oxidant in the present invention can be obtained from any suitable source, which includes, for example, the autoxidation of secondary alcohols using air or another source of molecular oxygen. Suitable secondary alcohols include both aliphatic alcohols such as isopropanol and cyclohexanol, as well as aromatic alcohols such as methyl benzyl alcohol alpha and anthrahydroquinones (including substituted alkyl anthrahydroquinones). The crude reaction product by which it is generated can either be used directly in the epoxidation process of this invention or, if so desired, be purified, fractionated, concentrated, ion exchanged, or otherwise processed before such use . For example, acetone generated can be separated as a by-product of auto-oxidation, in whole or in part, of hydrogen peroxide by distillation (where acetone is relatively volatile) or by extraction with water (where acetone is substantially immiscible with or insoluble). in water). When using hydrogen peroxide per se as a reagent, it will generally be desirable to employ hydrogen peroxide concentrations of from about 1 to 20 weight percent in the liquid phase within the reaction zone. The hydrogen peroxide can alternatively be generated in situ by, for example, combining oxygen, hydrogen, a noble metal such as Pd (which can be impregnated in or otherwise supported on the titanium containing zeolite), olefin, zeolite and tertiary amine. oxide thereof within a reaction zone under conditions effective to accompany the production of hydrogen peroxide and contemporary olefin epoxidation. The present invention can thus easily be adapted for use in the epoxidation processes described in JP 4,352771, JP H8-269029, JP H8-269030, WO 96/02323, WO 97/25143, DE 1 9600709, WO 97. / 3171 1, and WO 97/47386. The unsaturated ethylenically epoxidized substrate in the process of this invention is preferably an organic compound having from two to ten carbon atoms and at least one ethylenically unsaturated functional group (ie, a carbon-carbon double bond) and can be a straight or branched chain cyclic aliphatic olefin. There may be more than one carbon-carbon double bond in the olefin; in this way, dienes, trienes, and other polyunsaturated substrates can be used. Olefin production methods are well known in the art. For example, the olefin to be used in the process of this invention can be generated by dehydrogenation of the corresponding saturated compound. Exemplary suitable olefins for use in the process of this invention include ethylene, propylene, butenes, butadiene, pentenes, isoprene, 1 -hexene, 3-hexene, 1-heptene, 1-ketene, diisobutylene, 1 -nonne, trimers and tetramers of propylene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclooctadiene, dicyclopentadiene, methylenecyclopropane, methylenecyclopentane, methylenecyclohexane, vinylcyclohexane, and vinyl cyclohexene. The olefin mixtures can be epoxidized and result in a mixture of epoxides either used in the mixed form or separated in the different component epoxides. The process of this invention is useful especially for the epoxidation of the C2-C10 olefins having the general structure R1 R3 \ / C = C / \ where R1, R2, R3, and R4 are the same or different and are selected from the group consisting of hydrogen and C? -C8 alkyl (selected such that the total number of carbons in the olefin does not exceed 1 0). The process of this invention is also suitable for use in epoxidation olefins containing other functional groups than the aliphatic hydrocarbyl elements. For example, the carbon-carbon double bond can be substituted with groups such as -CO2H, -CO2R, -CN, or -OR where R is a substitute for alkyl, cycloalkyl, aryl or aralkyl. The radicals R1, R2, R3, and R4 in the structural formula shown above which may contain aryl, aralkyl, halo, nitro, sulphonic, cyano, carbonyl (eg, acetone, aldehyde), hydroxyl, carboxyl (e.g., ester) , acid) or ether groups. Examples of such olefins include allyl alcohol, styrene, allyl chloride, allyl methyl ether, allyl phenyl ether, methyl methacrylate, acrylic acid, methyl acrylate, stilbene, and the like. The amount of hydrogen peroxide relative to the amount of olefin is not critical, but more suitably the molar ratio of olefin: hydrogen peroxide is from about 100: 1 to 1: 10 when the olefin contains an ethylenically unsaturated group. The molar ratio of the ethylenically unsaturated groups in the olefin to the hydrogen peroxide is more preferably in the range of from 1: 2 to 10: 1. The titanium containing zeolites useful as catalysts in the epoxidation step of the process comprise the class of zeolitic substances wherein the titanium atoms are substituted for a portion of the silicone atoms in the lattice infrastructure of a molecular filter. Such substances are well known in the art. Preferred titanium-containing zeolites include the class of molecular filters commonly referred to as titanium silicalites, particularly "TS-1" (having an MFl topology analogous to that of aluminosilicate zeolites ZSM-5), "TS-2" (having an MEL topology analogous to that of the aluminosilicate zeolites ZSM-1 1), and "TS-3" (as described in Belgian Pat. No. 1, 001, 038). Also suitable for use are molecular filters containing titanium having infrastructure structures isomorphic to beta zeolite, mordenite, ZSM-48, ZSM-1 2, and MCM-41. The titanium containing zeolite preferably does not contain other elements than titanium, silicone and oxygen in the grid infrastructure, although minor amounts of boron, iron, aluminum, and the like may be present. Other metals such as tin or vanadium may also occur in the lattice infrastructure of the zeolite in addition to titanium, as described in US Pat. of E.U. Nos. 5,780,654 and 5,744,619. Preferred titanium-containing zeolite catalysts, suitable for use in the process of this invention will generally have a composition corresponding to the following empirical formula xTiO2: (1 -x) SiO2, where x is between 0.0001 and 0.500. More preferably, the value of x is from 0.01 to 0.125. The molar ratio of Si: Ti in the lattice framework of the zeolite is advantageously 9.5: 1 to 99: 1 (more preferably, 9.5: 1 to 60: 1). The use of relatively titanium rich zeolites may also be desirable.

The amount of the catalyst used is not critical, but should be sufficient in order to substantially accompany the desired epoxidation reaction in a particularly short period of time. The optimum amount of the catalyst will depend on a number of factors including the reaction temperature, reactivity and concentration of olefin, concentration of hydrogen peroxide, type and concentration of organic solvent as well as the activity of the catalyst and the type of reactor or system of reaction (ie, series against continuous) used. In a series type or mixing reaction, for example, the amount of the catalyst will typically be from 0.001 to 1.0 grams per mole of olefin. In a fixed or packed platform system, the optimal amount of the catalyst will be influenced by the flow velocity of the reagents through the fixed platform; Typically, from 0.05 to 2.0 kilograms of hydrogen peroxide per kilogram of catalyst per hour will be used. The concentration of titanium in the liquid phase reaction mixture will generally be from about 10 to 10,000 ppm. The catalyst can be used in powder, pill, microsphere, eliminated, monolithic or of any other suitable physical form. The use of a binder (co-gel) or support in combination with the titanium containing zeolite can be advantageous. The bound or supported catalysts can be prepared by methods known in the art as effective for zeolite catalysts in general. Specific examples of supported titanium-containing zeolite catalysts suitable for use in the present process are described, for example, in 4,954,653, 5,354,875, 5,466,835, and 5,736,479.

Preferably, the binder or support is essentially non-acidic and does not catalyze the non-selective decomposition of hydrogen peroxide or the annular opening of the epoxide. Exemplary binders and carriers include titania, silica, alumina, silica-alumina, silicatria, silica-thoria, silica-magnesia, silica-zironia, silica-berilia, and ternary compositions of silica with other refractory oxides. Also useful are clays such as montmorillonites, kaolins, bentonites, haloisites, diquitas, nacrites, and ananxites. The proportion of zeolite: binder or support can vary from 99: 1 to 1: 99, but preferably is from 5:95 to 80:20. A critical feature of the process of this invention is the presence of a tertiary amine or tertiary amine oxide. Such additives are non-ionic in character, in contrast to the ionic species suggested by the prior art. Although the precise mechanism by which the enhanced epoxide selectivities of the process is performed is not known, it is believed that the tertiary amine or oxide interacts favorably with the titanium containing zeolite catalyst in order to suppress side reactions not desired such as annular epoxy aperture. In one embodiment, the catalyst is pretreated (i.e., prior to epoxidation) with the tertiary amine or oxide. A suitable pretreatment method comprises forming a mixture of the catalyst in a dilute solution of the tertiary amine or oxide in a suitable solvent and stirring the mixture at a temperature of from 20 ° C to 100 ° C for an effective time to incorporate sufficient tertiary amine or oxide in the zeolite. The catalyst is subsequently removed from the mixture by suitable means such as filtration, centrifugation, decanting, washing if desired (being careful not to remove all the tertiary amine or oxide), and thus, optionally, drying of the residual solvent. In a preferred embodiment, however, the tertiary amine or oxide is introduced into the reaction zone separately from the catalyst during epoxidation. For example, the tertiary amine or oxide may be suitably dissolved in the hydrogen peroxide feed, which will typically also contain a relatively polar solvent such as water, alcohol, and / or acetone. In a continuous process, the concentration of tertiary amine or oxide in the feed entering the reaction zone can be adjusted periodically as desired or necessary in order to optimize the epoxidation results achieved. It may, for example, be advantageous to use a tertiary amine or constant oxide concentration, to introduce portions of the tertiary amine or oxide in intermittent intervals, or to increase or decrease the tertiary amine or oxide concentration over time. The preferred type of tertiary amine or tertiary amine oxide to be used will vary in some way depending on other parameters of the olefin epoxidation process that are selected, but can easily be determined by routine experimentation. In contrast to the epoxidation process described in Pat. of E.U. No. 4,824,976, it is not necessary for the tertiary amine or oxide thereof to be soluble in water. Generally speaking, however, the use of an additive which is soluble in the liquid medium in which the epoxidation performs is preferred. Without wishing to be bound by any theory, it is believed that the ability of the tertiary amine or oxide to suppress unwanted ring-opening reactions of the epoxide that is formed during epoxidation is generally improved if the tertiary amine or oxide is sufficiently small in molecular size so as to be able to enter the pores of the titanium-containing zeolite. Thus, in the case of a relatively small pore zeolite such as titanium silicalite TS-1, 2,6-lutidine has been found to be much more effective than 2,6-di-tert-butyl pyridine. At the same time, however, it will typically be desirable to have the nitrogen atom of the tertiary amine or oxide which hinders space to some degree so as not to increase the epoxidation activity of the catalyst to an unacceptable degree. In certain embodiments of the invention, the tertiary amine or oxide thereof contains a single nitrogen atom and / or is a heterocyclic compound where the nitrogen is present in a cyclic structural element. However, two or more nitrogen atoms may be present. Aromatic heterocycles containing nitrogen are generally suitable for use. It has been found that pyridine, substituted pyridines and oxides thereof are especially effective in reducing the levels of annular opening side reactions that are observed during olefin epoxidation. For example, the substance to be added for that purpose may be a pyridine derivative substituted for one or both of the 2 and 6 positions of the pyridine ring with an alkyl group (eg, Ci-Ce) or halo. The substituted alkoxy and cyano pyridines can also be used. Tertiary amines in which the nitrogen atom binds to three carbon atoms are also generally useful in the present process. Other classes of tertiary amines and tertiary amine oxides suitable for use include, but are not limited to: trimethyl pyridines 2-halopyridines (chlorine, bromine, iodine) dihalopyridines (eg, 2,6-difluoropyridine) cyanopyridines (eg Compounds) monosubstituted such as 3-cyanopyridine) methylpyrimidines halopyrimidines pyrazines triazoles of 1 -alkyl (including halo and alkyl derivatives thereof) triazines (including halo and alkyl derivatives thereof) N, N-dialkyl anilines (including cyano derivatives, halo and alkyl thereof) anilines of halo-N, N-dialkyl alkyl anilines-N, N-dialkyl amines of alkyl dimethyl (eg where alkyl = C? -C18 hydrocarbon) phenyl pyridines of 2 or 4 dimethylamino? (including alkyl and halo derivatives thereof) 1-alkyl imidazoles (including alkyl and halo derivatives thereof) piperidines of 1-alkyl morpholines of 1-alkyl and oxides thereof. Mixtures of tertiary amines and tertiary amine oxides can be used. Tertiary amines and illustrative oxides thereof that can be used in the present process include, but are not limited to, the following amines and their corresponding oxides and isomers, analogs and homologs thereof: pyridine pyridine 2-methyl (2-picoline) ) quinoxaline quinoline pyrazine 2-methyl pyridine 3-methyl (3-picoline) pyridine 4-methyl (4-picoline) aniline N, N-dimethyl 2,6-lutidine 2,4-lutidine 3,4-lutidine pyridine 2,6 -diethyl pyridine 2,6-dipropyl pyridine 2-ethyl pyridine 2-propyl pyrazine 2,3-diethyl quinoline 2-methyl pyrrole 1, 2, 5-trimethyl 2-methoxypyridine carbazole 9-methyl phenanthridine acridine 2,2'-bipyridine indole 1 -methyl pyrimidine 2-fluoropyridine 2-chloropyridine 2-bromopyridine 2-iodopyridine 1,6-difluoropyridine 3-cyanopyridine triazide 1 -methyl imidazole 1 -methyl pyridine 2-dimethyl amino piperidine 1 -methyl The optimal concentration used of the amine tertiary or oxide will vary depending depending on the number of factors, including, for example, the chemical identity of the tertiary amine or oxide, temperature, solvent, space velocity, the type of zeolite containing selected titanium and the like, but can be easily determined by routine experimentation. Generally speaking, the level of the tertiary amine or oxide in the liquid phase epoxidation reaction mixture is desirably maintained at a level sufficient to provide a molar ratio of tertiary amine (or oxide): Ti in the range of from 0.5: 1 up to 50: 1. The epoxidation reaction temperature is preferably from 0 ° C to 1 00 ° C (more preferably from 30 ° C to 80 ° C), but should be selected in such a way as to achieve the selective conversion of the olefin to epoxide within a reasonably short period of time with the minimal non-selective decomposition of hydrogen peroxide. It is generally advantageous to carry out the reaction to achieve as high as possible a conversion of hydrogen peroxide, preferably at least 50%, more preferably at least 90%, more preferably at least 99%, consistent with reasonable selectivities. The optimum reaction temperature will be influenced by the concentration and activity of the catalyst, reactivity of the substrate, concentrations of the reactants, and type of solvent used, among other factors. Reaction or residence times of from about 10 minutes to 48 hours will typically be appropriate, depending on the variables identified above. The reaction is preferably performed at atmospheric pressure or at elevated pressure (typically, between 1 and 100 atmospheres). Generally, it will be desirable to keep the reaction components as a liquid mixture. For example, when an olefin such as propylene having a boiling point at atmospheric pressure which is less than the epoxidation temperature is used, superatmospheric pressure sufficient to maintain the desired concentration of propylene in the liquid phase is preferably used.

The epoxidation process of this invention can be carried out serially, continuously, or semi-continuously using any suitable type of reaction vessel or apparatus such as a fixed bed, transport bed, stirred mixture, or CSTR reactor. Known methods for conducting catalyzed epoxidations of metal using hydrogen peroxide will also generally be suitable for use. In this way, the reagents can all be combined at the same time or sequentially. For example, hydrogen peroxide and / or olefin can be added incrementally to the reaction zone. The epoxidation can be carried out in the presence of a suitable solvent in order to dissolve or disperse the reagents and facilitate temperature control. Suitable solvents include, but are not limited to, water, alcohols, (especially C 1 -C 10 aliphatic alcohols such as methanol and isopropanol), esters (especially aliphatic esters such as THF and MTBE), ketones (especially C 3 -C 10 acetonas such as acetone), and mixtures of such solvents. The reaction can be carried out alternatively using two liquid phases, i.e., an organic phase and an aqueous phase. Halogenated solvents such as dichloromethane, dichloroethane and chlorohencenes are examples of solvents suitable for use in such biphasic reaction systems. Once the epoxidation has been carried out to the desired degree of conversion, the epoxide product can be separated and recovered from the reaction mixture using any suitable technique such as fractional distillation, extractive distillation, liquid-liquid extraction, crystallization, or the like. . After being separated from the epoxidation reaction mixture by any suitable method such as filtration (as when using a mixing reactor, for example), the recovered titanium containing zeolite catalyst can be economically reused in subsequent epoxidations. When the catalyst is deployed in the form of a fixed bed, the epoxidation product extracted as a stream from the epoxidation zone will be essentially catalyst free with the catalyst to be retained within the reaction zone. Similarly, no unreacted olefin or hydrogen peroxide can be separated and recycled or otherwise disposed of. In certain embodiments of the present process where the epoxide is produced on a continuous basis, it may be desirable to periodically or constantly regenerate all or a portion of the catalyst used in order to maintain optimum activity and selectivity. Suitable regeneration techniques are well known and include, for example, calcination and solvent treatment. Regeneration may also include retreatment or reimpregnation with the tertiary amine or tertiary amine oxide. From the above description, a person skilled in the art will be able to easily make sure of the essential characteristics of this invention, and, without departing from the spirit and scope thereof, will be able to make several changes and modifications of the invention to adapt it to different uses, conditions, and modalities. EXAMPLES Example 1 A 100 mL Parr reactor equipped with a magnetic stir bar is charged with 34 grams of methanol, 200 mg. of 2,6-lutidine and 250 mg. of titanium silicalite Ts-1 containing 2.1% by weight of Ti (calcined at 540-550 ° C before use). After mixing for several minutes at room temperature, 8 grams of 30% aqueous hydrogen peroxide are added. The closed reactor is thus charged with 14 grams of propylene from a Hoke pressure vessel that uses 400 psig of nitrogen. The reactor is heated to 40 ° C for 30 minutes and cooled to 20 ° C using an ice bath. The reactor gases are vented in a gas bag. The reactor is pressurized to 400 psig with nitrogen and the gases are vented in another gas bag. Gas bags are analyzed by GC for oxygen, propylene oxide, propylene and CO2. The volumes of the bags are measured using a wet test meter. The liquid phase is analyzed by GC for oxygenated products using acetonitrile as a standard and by LC for carboxylic acids. The conversion of hydrogen peroxide is measured by reaction of an aliquot of the recovered liquid with a sodium iodide and titration with sodium thiosulfate. The above reaction gave propylene oxide and isomers of propylene glycol monomethyl ether at 98.5 and 0.8% selectivity, respectively. The selectivities were based on the products observed in a propylene base. The hydrogen peroxide conversion was 74%. When the amount of 2,6-lutidine was reduced by one-half, the selectivity to propylene oxide was still relatively high at 97%. Only 2.8% selectivity to monomethyl esters of propylene glycol was observed. The hydrogen peroxide conversion was 88%. By way of comparison, when the same experiment was repeated in the absence of 2,6-lutidine only 91.6% of propylene oxide selectivity was obtained. The selectivity to monomeryl esters of unwanted propylene glycol was 7.7%. A hydrogen peroxide conversion of 94% was achieved. Example 2 The procedure of Example 1 was repeated, but using a different series of titanium silicalite TS-1 containing 1.3% by weight of Ti and a longer reaction time (2.5 hours). In the presence of 2,6-lutidine, 98% selectivity of propylene oxide, 1.7% selectivity of propylene glycol monomethyl ether and 0% selectivity of propylene glycol in a peroxide conversion were observed. 69% hydrogen Without 2,6-lutidine, the selectivity of propylene oxide dropped to 78% while the amount of the annular aperture products reached significantly (14% selectivity to propylene glycol monomethyl ether, 4.9% selectivity to glycol of propylene). The conversion of hydrogen peroxide was 79%. Example 3 The procedure of Example 2 was repeated, but using pyridine oxide instead of 2,6-lutidine. Although 94.7% selectivity of propylene oxide and 4.8% selectivity of propylene glycol were observed, the conversion of hydrogen peroxide dropped to 25%. Examples 4-27 The procedure of Example 1 was repeated, except for the use of a different series of titanium silicalite TS-1 and tertiary amines or different tertiary amine oxide additives. Example 4 is a comparative example (no additive). The results obtained are shown in Table 1.

TABLE 1 propylene, (D PG = propylene glycol F DPM = monomethyl esters of dipropylene glycol ** of selectivity based on the products observed in a propylene base *** of the comparative example

Claims (21)

1. CLAIMS 1. A method for epoxidizing an olefin comprising contacting said olefin with hydrogen peroxide in a reaction zone in the presence of a titanium-containing zeolite catalyst and an additive comprising a tertiary amine, a tertiary amine oxide or a mixture of the same.
2. 2. A method according to claim 1, characterized in that the tertiary amine or tertiary amine oxide has a molecular size such that it can enter the pores of the zeolite catalyst containing titanium.
3. A method according to claim 1 or 2, characterized in that the tertiary amine or tertiary amine oxide has at least one of the carbon atoms that directly attach to the tertiary nitrogen atom attached to no more than a hydrogen atom.
4. A method according to any of the preceding claims, characterized in that the tertiary amine or tertiary amine oxide comprises 1, 2 or 3 nitrogen atoms at least one of which is a tertiary nitrogen atom.
5. A method according to any one of the preceding claims, characterized in that the additive comprises a heterocycle containing at least one ring of a nitrogen atom.
6. 6. A method according to any of the preceding claims, characterized in that the additive comprises an aromatic compound.
7. A method according to any one of the preceding claims, characterized in that the additive is selected from the group consisting of pyridine, substituted pyridines of halo-, cyano-, alkoxy-, dialkylamino- and alkyl-, oxides and anilines N, N-dialkyl from the same.
8. A method according to claim 7, characterized in that the additive is a pyridine derivative substituted for one or both of the 2 and 6 positions of the pyridine ring with an alkyl or halo group.
9. A method according to claim 7 or 8, characterized in that the additive is selected from the group consisting of 2,6-lutidine, 2-picoline, 2-fluoropyridine, N, N-dimethylaniline, 2-methoxypyridine, 3-cyanopyridine, 4-dimethylamino benzonitrile, 2-halopyridines, quinoline and oxides thereof.
10. A method according to any of the preceding claims, characterized in that the titanium-containing zeolite catalyst has a topology MF1, MEL or zeolite beta. eleven .
11. A method according to any of the preceding claims, characterized in that the titanium containing zeolite comprises titanium silicalite TS-1.
12. 12. A method according to any of the preceding claims, characterized in that the catalyst containing titanium has a composition corresponding to the chemical formula xTiO2: (1 -x) SiO2 wherein x is from 0.01 to 0.125.
13. A method according to any one of the preceding claims, characterized in that the amount of additive is sufficient to provide a molar ratio of additive: titanium from 0.5: 1 to 50: 1.
14. 14. A method according to any of the preceding claims, characterized in that the olefin is an aliphatic olefin C2-C-i or -
15. 15. A method according to claim 14, characterized in that the olefin comprises propylene.
16. 16. A method according to any of the preceding claims, characterized in that the hydrogen peroxide is generated in situ.
17. 17. A method according to any of the preceding claims, characterized in that said contacting is carried out at a temperature from 0 ° C to 1 00 ° C.
18. 18. A method according to any of the preceding claims, characterized in that said reaction is carried out in a liquid phase.
19. 19. A method according to claim 18, characterized in that the liquid phase is comprised of a solvent selected from the group consisting of water, C1-C10 alcohols, C3-C10 acetones, aliphatic esters and mixtures thereof; for example methanol. A method according to any of the preceding claims, characterized in that the titanium-containing zeolite catalyst is deployed in the form of a fixed bed within the reaction zone and the olefin, hydrogen peroxide, solvent, and additive they are introduced into the reaction zone and a stream of product comprised of an epoxide corresponding to the olefin in the reaction zone is extracted. twenty-one . A method according to any of the preceding claims, characterized in that the hydrogen peroxide is generated in situ.