A process and systems for the epoxidation of an olefin

The present invention relates to the process of epoxidation of olefins, which comprises reacting a feedstock containing olefins, oxygen and reaction modifiers in the presence of a highly selective silver-based catalyst. The present invention also relates to suitable systems for use in connection with the process.

Catalytic epoxidation of olefins using silver-based catalysts has been known so far. Conventional silver-based catalysts have low selectivity for olefin oxides and are considered unfavorable. For example, when using conventional catalysts for epoxidation of ethylene, the selectivity for ethylene oxide, expressed as a fraction of converted ethylene, does not reach values above the 6/7 or 85.7 mol% limit. Therefore, it has long been thought that this limit indicates the theoretical maximum selectivity of this reaction based on the stoichiometry of the reaction equation below. 7C₂H₄+ 6O₂=> 6C₂H₄O + 2CO₂+ 2H₂O See Kirk-Othmer's Encyclopedia of Chemical Technology, 3rd Edition, Volume 9, 1980, p.445.

However, current silver-based catalysts have become more selective for olefin oxide production. When using current catalysts for ethylene epoxidation, selectivity for ethylene oxide can reach values above the 6/7 or 85.7 mol% limit. Such highly selective catalysts, which may include silver, rhenium, at least one additional element, and optionally rhenium co-catalyst as active ingredients, are EP-A-266015, and several subsequent patents. It is published in.

In addition to better catalysts, reaction modifiers have been found that may be added to the feedstock to improve selectivity (see, eg, EP-A-352850). This type of reaction modifier suppresses the unwanted oxidation of olefins or olefin oxides to carbon dioxide and water in connection with the formation of the desired olefin oxide, but the mechanism has not yet been elucidated. Suitable reaction modifiers include, for example, organic halides.

When applying a reaction modifier, the concentration of the reaction modifier in the feedstock can be selected so that this type of selectivity is optimal. By a trial-and-error procedure, that is, by gradually changing the reaction modifier supply ratio and monitoring the effect on selectivity, the concentration at which the selectivity is optimized can be found during the operation of the epoxidation process. However, in this type of procedure, there may be operational problems and the process will be run for a period of time under conditions that do not reach the most economical conditions. In addition, if the feedstock composition changes, trial and error procedures will need to be redone to adapt the concentration of the reaction modifier to the new reaction conditions.

<p> According to the present invention, the operator of the epoxidation process can change the concentration of the reaction modifier so that the relative amount Q of the reaction modifier is maintained at a constant level substantially, preferably completely. Undesirable fluctuations in selectivity can be avoided when the feedstock composition changes in the concentration of the reaction modifier. Here, the relative amount Q is basically the ratio of the molar amount of the reaction modifier in the feedstock to the molar amount of hydrocarbons in the feedstock. In other words, the teaching of the present invention is that the concentration of reaction modifier required to achieve a certain effect on selectivity is proportional to the concentration of hydrocarbons present in the feedstock. As a result, this effect on selectivity is maintained when the feedstock composition is varied by varying the reaction modifier concentration proportionally or substantially proportionally to any variation in the hydrocarbon concentration. It means that you can do it. This is more independent of any variation in feedstock composition than variations associated with hydrocarbons and / or reaction modifiers. Therefore, the advantage of the present invention is that the epoxidation process can be significantly simpler and smoother to control than without the present invention.</p><p> In addition, there may be differences in the behavior of various hydrocarbons that may be present in the reaction mixture in a quantitative sense, and therefore, in calculating Q, the molar amount of hydrocarbons is used as the hydrocarbon. It was also found that it is more preferable to replace it with the so-called effective molar amount of. As described below, the effective molar amount of hydrocarbons in the feedstock can be calculated from the feedstock composition, which can explain the cause of the difference in behavior between the various hydrocarbons present. ..</p><p> Furthermore, it has been found that there may be differences in the behavior of different reaction modifiers in a quantitative sense, as it often happens that a mixture of reaction modifiers is present. Therefore, when calculating Q, it may be preferable to replace the molar amount of the reaction modifier with the so-called effective molar amount of the active species of the reaction modifier. As described below, the effective molar amount of the active species of the reaction modifier in the feedstock can be calculated from the feedstock composition, which can explain the difference in behavior of the different reaction modifiers. ..</p><p> Without being bound by theory, unlike other components of the feedstock, hydrocarbons (eg, olefins and saturated hydrocarbons, if any) have the ability to remove or decompose reaction modifiers from the catalyst. It is considered to have. The teaching of the present invention is that what needs to be maintained in order to maintain the effect of the reaction modifier is not the concentration of the reaction modifier at a location in the reaction mixture other than the catalyst surface, but on the catalyst. It is the concentration of the active species of the pledge. Differences in the ability of various hydrocarbons in the removal / decomposition process, and differences in the effectiveness of various reaction modifiers and their susceptibility to the removal / decomposition process, are calculated as effective molars, as described above. And can be explained by application.</p>

<p> Therefore, the present invention provides a process for epoxidation of olefins, which provides a feedstock containing olefins, oxygen and reaction modifiers in the presence of a silver-based catalyst, for hydrocarbons present in the feedstock. The process comprises reacting the reaction modifier present in a relative amount Q, which is the ratio of the effective molar amount of the active species of the reaction modifier present in the feedstock to the effective molar amount. But, -Q value to Q₁And the steps to operate in the first operation phase, -Next, the supply material composition is different from the supply material composition used in the first operation phase, and the value of Q is Q.₂And thereby the quotient Q₂/ Q₁Includes steps to run in the second run phase so that the value of is in the range 0.5-1.5.</p><p> In one embodiment, the second step is a feedstock hydrocarbon composition and reaction modifier composition at least one of which is different from the feedstock hydrocarbon composition and reaction modifier composition used during the first operating phase. Operates in.</p><p> The present invention also provides a suitable system for carrying out the processes of the present invention, the system supplying a reactor holding a silver-based catalyst and a feedstock containing olefins, oxygen and reaction modifiers to the reactor. And a control means for controlling the feedstock and / or the feedstock composition, which is a reaction modifier present in the feedstock relative to the effective molar amount of hydrocarbons present in the feedstock. A feedstock and / or feedstock composition comprising a modifier control means for controlling a reaction modifier present in the feedstock in a relative amount Q, which is the ratio of the effective molar amounts of the active species of. The control means for controlling and the supply material control means -The value of Q is Q₁The steps to operate in the first operation phase and -The next step is to operate in the second operation phase, where the supply material composition is Q and the value is Q.₂And thereby the quotient Q₂/ Q₁It is configured to control process steps, including steps that differ from the feedstock composition used during the first operating phase, where the value of is in the range 0.5-1.5.</p><p> The present invention also includes computer-readable media and computer-readable media recorded on computer-readable media suitable for instructing the data processing system of a computer system to perform calculations for the processes of the invention. Provides computer program products that include various program codes.</p><p> The present invention also provides a computer system including the computer program product of the present invention and a data processing system configured to receive instructions read from the computer program product.</p><p> The present invention also provides a process of epoxidation of olefins, which is generally referred to as the process of reacting an olefin with a feedstock containing oxygen and a reaction modifier in the presence of a silver-based catalyst. But, -Steps to operate in the first operation phase and -Then the feedstock composition operates in a second run phase that is different from the feedstock composition used during the first run phase so that the concentration of the active species of the reaction modifier on the catalyst remains substantially unchanged. Including steps.</p>

The epoxidation process of the present invention can be carried out in many ways, but as a gas phase process, that is, as a process in which the feedstock comes into contact with the catalyst, which is usually present as a solid in the packed bed, in the gas phase. Is preferable. Normally, this process shall be executed in a continuous manner. In industrial scale operations, the process of the present invention weighs at least 10 kg, eg at least 20 kg, often 10.²~10⁷In the range of kg, more often 10³~10⁶It may contain a catalyst amount in the range of kg.

The olefin used in the epoxidation process of the present invention may be an aromatic olefin such as styrene, or any olefin such as a conjugated or unconjugated diolefin such as 1,9-decadien or 1,3-butadiene. Usually, this olefin is a monoolefin such as 2-butene or isobutene. Preferably, for example, the olefin is a mono-α-olefin such as 1-butene, propylene or the like. The most preferred olefin is ethylene.

The olefin concentration in the feedstock is not essential to the present invention and can be selected in a wide range. Normally, the olefin concentration in the feedstock is at most 80 mol% with respect to the total feedstock. Preferably, in the same manner, the range is 0.5 to 70 mol%, especially 1 to 60 mol%. As used herein, the feedstock is considered to be a composition that comes into contact with the catalyst.

The epoxidation process of the present invention may be air-based or oxygen-based. See Kirk-Othmer's Encyclopedia of Chemical Technology, 3rd Edition, Volume 9, 1980, pp. 445-447. Air-based processes use air or oxygen-concentrated air as the source of the oxidant, while oxygen-based processes use high-purity (&gt; 95 mol%) oxygen as the source of the oxidant. Currently, most epoxidation plants are oxygen-based, which is also a preferred embodiment of the present invention.

The oxygen concentration in the feedstock is not essential to the present invention and can be selected in a wide range. However, in practice oxygen is usually used at concentrations that avoid flammable conditions. Generally, the concentration of oxygen used is in the range of 1 to 15 mol%, usually 2 to 12 mol% of the total feedstock.

In order to keep the state out of the range of flammable conditions, the concentration of olefin may be increased and the concentration of oxygen in the feedstock may be decreased. The actual safe operating area depends on the reaction conditions such as reaction temperature and pressure in addition to the raw material composition.

A reaction modifier shall be present in the feedstock to suppress the unwanted oxidation of the olefin or olefin oxide to carbon dioxide and water in order to increase the appropriate selectivity for the production of the desired olefin oxide. .. In particular, many organic compounds such as organic halides and organic nitrogen compounds may be used as reaction modifiers. Nitrogen oxides, hydrazines, hydroxylamines or ammonia may be used as well. Under operating conditions for olefin epoxidation, the nitrogen-containing reaction modifiers are nitrates or nitrite precursors, i.e. they are so-called nitrate-producing or nitrite-producing compounds ( See, for example, EP-A-3642, US-A-4822900).

Organic halides are preferred reaction modifiers, with organic bromides and even organic chlorides being particularly preferred. Preferred organic halides are chlorohydrocarbons or bromohydrocarbons. More preferably, they are selected from the group of methyl chloride, ethyl chloride, ethylene dichloride, ethylene dibromide, vinyl chloride or mixtures thereof. The most preferred reaction modifiers are ethyl chloride and ethylene dichloride.

Suitable nitrogen oxides have the general formula NO_XAnd here, where X (representing the ratio of the number of oxygen atoms to the number of nitrogen atoms) is in the range 1-2. Examples of these nitrogen oxides include NO and N.₂O₃And N₂O₄Can be mentioned. Suitable organic nitrogen compounds are nitro compounds such as nitromethane, 1-nitropropane, 2-nitropropane, nitroso compounds, amines, nitrates and nitrites. In a preferred embodiment, nitrate-producing or nitrite-producing compounds such as nitrogen oxides and / or organic nitrogen compounds are used with organic halides, especially with organic chlorides.

The reaction modifier may be supplied as a single compound upon contact with the catalyst, but may function as a reaction modifier and may be present in the feedstock when using the recycling method. Compounds may be produced. For example, when ethyl chloride is used in the ethylene oxide process, the feedstock may practically contain ethyl chloride, vinyl chloride, ethylene dichloride and methyl chloride.

Reaction modifiers are usually at low concentrations in the feedstock, for example up to 0.1 mol% of the total feedstock, eg 0.01 × 10.^-4Effective when used up to 0.01 mol%. Especially when the olefin is ethylene, the reaction modifier is 0.05 × 10 in the feedstock.^-4From 50 × 10^-4Up to mol%, especially 0.2 x 10 for all feedstocks^-4From 30 × 10^-4It is preferably present in concentrations up to mol%.

In addition to olefins, oxygen and reaction modifiers, the feedstock may contain one or more optional components such as carbon dioxide, water, inert gases, saturated hydrocarbons and the like. Carbon dioxide and water are by-products of the epoxidation process. Carbon dioxide usually has an adverse effect on catalytic activity. Generally, concentrations of more than 25 mol%, preferably more than 10 mol%, of carbon dioxide in the feedstock shall be avoided relative to the total feedstock. Use low concentrations of carbon dioxide of 1 mol% or less of the total feedstock. Water may be introduced into the feedstock as a result of the recovery of olefin oxides and carbon dioxide from the reaction product. Water usually has an adverse effect on catalytic activity. Generally, concentrations of water greater than 3 mol%, preferably greater than 1 mol%, in the feedstock with respect to the total feedstock shall be avoided. Use low concentrations of carbon dioxide, 0.2 mol% or less, relative to the total feedstock. Inactive gases such as nitrogen, argon, or mixtures thereof, may be present in the feedstock at a concentration of 0.5-95 mol%. In air-based processes, the inert gas may be present in the feedstock at a concentration of 30-90 mol%, usually 40-80 mol%. In oxygen-based processes, the inert gas may be present in the feedstock at a concentration of 0.5-30 mol%, usually 1-15 mol%. Suitable saturated hydrocarbons are propane and cyclopropane, especially methane and ethane. When saturated hydrocarbons are present, they may be present in an amount of up to 80 mol%, particularly up to 75 mol%, based on the total feedstock. Often in an amount of at least 30 mol%, more often at least 40 mol%. Saturated hydrocarbons may be added to the feedstock to increase the oxygen combustion limit.

The relative amount Q of the reaction modifier is the ratio of the effective molar amount of the active species of the reaction modifier present in the feedstock to the effective molar amount of the hydrocarbons present in the feedstock. Yes, both molar quantities are expressed in the same unit, for example, as mol% with respect to the total supply raw materials.

To calculate the effective molar amount and Q value of the active species of the reaction modifier, if the reaction modifier is a halogen compound, the number of active species is considered to be the number of halogen atoms. When the reaction modifier is a nitrate-forming or nitrite-forming compound, the number of active species is considered to be the number of nitrogen atoms. This means, for example, that 1 mole of ethylene dichloride provides 2 moles of active species, that is, all of the chlorine atoms present provide one active species. On the other hand, reaction modifiers, which are methyl compounds such as methyl chloride and methyl bromide, are less reactive and therefore 2-5 mol, especially 2.5-3.5 mol, preferably 3 mol of methyl. It was also found that the compound appears to supply 1 mol of active species. This number can be measured and confirmed by routine experimental work, so that the methyl compound in question is less capable of separating the heteroatom in question (eg halogen or nitrogen atoms) if considered without being constrained by theory. Then, this number is expected to be larger. So, for example, the feedstock is ethyl chloride 2x10.^-4Mol%, 3x10 of vinyl chloride^-4Mol%, 1x10 of ethylene dichloride^-4Mol%, 1.5 x 10 of methyl chloride^-4When containing mol%, the effective molar amount of the active species of the reaction modifier is 2 × 10.^-4×1+3×10^-4×1+1×10^-4×2+1.5×10^-4×1/3=7.5×10^-4It can be calculated as mol%.

In summary, the effective molar amount of the active species of the reaction modifier present in the feedstock is the product of the multiplications obtained by multiplying the molar amount of each reaction modifier present in the feedstock by a factor. It can be calculated by summing, but here the factor of the reaction modifier, which is a methyl compound, is in the range of 1/5 to 1/2, more usually 1 / 3.5 to 1 / 2.5. Each factor represents the number of active heteroatoms, especially per molecule of the reaction modifier in question, with the recognition that it may be in the range up to, and is appropriately 1/3. It shall represent a halogen atom and / or a nitrogen atom.

The hydrocarbons present in the feedstock shall include the olefins present and any saturated hydrocarbons. As mentioned above, the hydrocarbons in the feedstock have the ability to remove / decompose reaction modifiers from the catalyst surface, and the extent to which they have this ability may vary for various hydrocarbons. It seems that there is no such thing. To explain these differences (relative to ethylene), the effective molars of hydrocarbons are calculated by multiplying the factor by the molars of each hydrocarbon that are present after summing the molars. Here, the ethylene factor is set to 1 by definition, the methane factor is at most 0.5 or at most 0.4, usually in the range of 0 to 0.2, and more usually in the range of 0 to 0.1, and the ethane factor. Is in the range of 50 to 150, more usually up to 70 to 120; and the factors of higher hydrocarbons (ie, having at least 3 carbon atoms) are in the range of 10 to 10000 and more commonly. Is from 50 to 2000. These factors can be measured and confirmed by routine experimental work, and, without being constrained by theory, the factors are thought to increase as the hydrocarbon in question has a greater ability to generate radicals. There is. Suitable factors for methane, ethane, propane and cyclopropane are 0.3, 85, 1000 and 60 for ethylene, respectively. As an example, if the feedstock contains 30 mol% ethylene, 40 mol% methane, 0.4 mol% ethane, 0.0001 mol% propane, the effective molar amount of hydrocarbons is 30 x 1 + 40. It can be calculated as × 0.1 + 0.4 × 85 + 0.0001 × 1000 = 68.1 mol%.

When ethylene oxide is produced from ethylene in the absence of more hydrocarbons, the effective molar amount of hydrocarbons is equal to the actual molar amount, and any amount of methane added has a relatively small contribution. However, it should be noted that the addition of ethane or higher hydrocarbons to the ethylene feedstock significantly contributes to the effective molar quantity.

A reasonable value for Q is at least 1x10^-6And especially at least 2x10^-6Is. A suitable value for Q is at most 100 x 10^-6And especially at most 50x10^-6Is.

During any operational phase of the process, the concentration of the reaction modifier, and thus the value of Q, is adjusted to achieve optimal selectivity for olefin oxide formation under general reaction conditions. This is particularly relevant to embodiments of the present invention in which the catalyst is a highly selective silver-based catalyst, as shown below.

According to the present invention, when the composition of the feedstock is changed, the concentration of the reaction modifier may be changed in the same manner so that the value of Q does not change substantially.₁Is Q₂Means approximately equal to, or preferably equal to,. Preferably, the quotient Q₂/ Q₁The value of is in the range of 0.8 to 1.2, especially 0.9 to 1.1, and further 0.95 to 1.05. Most preferably, the quotient Q₂/ Q₁The value of is equal to 1.

Thus, in the present invention, a reaction modifier that can be used in the second operational phase of the epoxidation process by calculation, depending on the variation in feedstock composition with respect to the amount or type of feedstock constituents. It is possible to determine the desired composition of the hydrocarbon (s) or in the feedstock (s). In a preferred embodiment, depending on the amount or type of hydrocarbons present in the feedstock, the reaction modifiers (s) in the feedstock that can be used in the second phase of operation. The desired concentration can be calculated. In another embodiment, hydrocarbons in the feedstock (s) that can be used in the second phase of operation, depending on the amount or type of reaction modifier (s) present in the feedstock. The desired concentration (s) can be calculated. In yet another embodiment, it is preferable not to change the amount or type of hydrocarbon (s), but depending on the type of reaction modifier (s) present in the feedstock, a second. The desired concentration of reaction modifiers (s) in the feedstock that can be used during the operational phase of In yet another embodiment, the second operation depends on the type of hydrocarbon (s) in the feedstock, although it is preferable not to change the amount or type of reaction modifier (s). The desired concentration of hydrocarbons (s) in the feedstock that can be used during the phase can be calculated.

There may be various reasons for the occurrence of fluctuations in the composition of the feedstock. For example, the production rate of olefin oxide may be controlled by changing the oxygen concentration or the olefin concentration, or the combustion limit may be changed by changing the concentration of saturated hydrocarbon. The carbon dioxide concentration in the feedstock may change as a result of changes over time in the catalyst. The concentration of the inert gas in the feedstock may fluctuate as a result of fluctuations in the concentration of this type of gas in the oxygen supplied to the process. In addition, when using highly selective catalysts, selectivity may be improved at highly advanced stages of catalyst aging by increasing the ethylene content of the feedstock (US-6372925-B1 and WO- See A-01 / 96324, non-advanced published PCT patent application PCT / US01 / 18097). By using the present invention, when the process is operating with optimum selectivity, the deviation of selectivity from the optimum conditions will be smaller due to fluctuations in the feedstock composition, or the selectivity will be optimal. It may even be maintained at the level of. By using the present invention when the process is not running in a state of optimum selectivity, the application of the present invention further prevents the process from deviating from the optimum selectivity.

Any variation in the feedstock composition may be gradual or gradual, and any variation in the feedstock composition may be reactively modified so that the value of Q remains substantially unchanged or remains constant. It occurs with fluctuations corresponding to the concentration of the agent. Usually, the fluctuation of the feedstock composition fluctuates in parallel with the concentration of the reaction modifier.

The epoxidation process can be carried out over a wide range of reaction temperatures. Preferably, the reaction temperature is in the range of 180 to 340 ° C, more preferably in the range of 190 to 325 ° C, especially in the range of 200 to 300 ° C. It is preferable to gradually increase the reaction temperature as the catalyst changes over time to compensate for the decrease in catalyst activity. However, it is preferable to substantially change the composition of the feedstock without changing the reaction temperature. Even if there is, it is preferable that the reaction temperature fluctuation caused by the fluctuation of the feedstock composition is often less than 10 ° C, more often less than 5 ° C, and particularly preferably less than 2 ° C. Most preferably, the composition of the feedstock is changed without any change in the reaction temperature.

Usually, the silver-based catalyst is a supported catalyst. The carrier can be selected from a wide range of inert carriers. This type of carrier may be a natural or artificial inorganic material, including alkali earth metal carbonates such as silicon carbide, clay, pumice, zeolites, charcoal, and calcium carbonate. Fire resistant carriers such as alumina, magnesia, zirconia and silica are preferred. The most preferred carrier is α-alumina.

The carrier material is porous and has a surface area of 20 m as measured by the BET method.²Less than / g, especially 0.05 to 20m²It is preferably up to / g. The BET surface area of the carrier ranges from 0.1 to 10, especially 0.1 to 3.0 m.²More preferably up to / g. The BET surface area referred to here is considered to be measured by the method described by Brunauer, Emmet and Teller in J. Am. Chem. Soc., Vol. 60, 1938, pp. 309-316.

Silver-based catalysts include silver and additional elements or compounds thereof. Further suitable elements are nitrogen, sulfur, phosphorus, boron, fluorine, group IA metals, group IIA metals, renium, molybdenum, tungsten, chromium, titanium, hafnium, zirconium, vanadium, tarium, thorium, tantalum, niobium, gallium, You can choose from a group of germanium, and mixtures thereof. Preferably, the Group IA metal is selected from lithium, potassium, rubidium and cesium. Preferably, the Group IA metals are lithium, potassium and / or cesium. Preferably, the Group IIA metal is selected from calcium and barium. If possible, additional elements may be appropriately given in the form of salts or acids as oxyanions such as sulfates, borates, perrhenates, molybdenum, or nitrates.

It is preferable to use a highly selective silver-based catalyst. Highly selective silver-based catalysts include, in addition to silver, compounds that produce one or more rhenium, molybdenum, tungsten, group IA metals, nitrates or nitrites, which are elements (with respect to the total amount of catalysts). Rhenium, molybdenum, tungsten, group IA metal, nitrogen) are calculated, and each may be present in an amount of 0.01 to 500 mmole / kg. The specific selection of nitrate or nitrite-producing compounds and the nitrate or nitrite-producing compounds is determined as set forth in the preceding article. Compounds that produce renium, molybdate, tungsten, or nitrates or nitrites may be appropriately given in the form of salts or acids as oxyanions or perrhenates, molybdates, tungstenates or nitrates.

Particularly preferred are highly selective silver-based catalysts containing rhenium in addition to silver. This type of catalyst is known as EP-A-266015. These are broadly selected from silver, rhenium or compounds thereof, rhenium or additional elements other than this compound (shown in the previous article), and in some cases sulfur, phosphorus, boron, one or more of these compounds. Contains a good rhenium co-catalyst.

When calculated as an element relative to the total catalyst, the preferred amount of constituents of the silver-based catalyst is: -10 to 500 g / kg of silver, -0.01-50 mmol / kg rhenium, if present -Additional elements (s) of 0.1-500 mmol / kg, if any, -If present, each is 0.1-30 mmol / kg rhenium co-catalyst (s).

The epoxidation process is preferably carried out at a reactor suction pressure in the range of 1000 to 4000 kPa. "GHSV" or Gas Hourly Space Velocity is the unit volume of gas at standard temperature and pressure (0 ° C, 1 atm (ie 101.3 kPa)) per unit volume of the filling catalyst. is there. If the epoxidation process is a vapor phase process using a packed catalyst bed, the GHSV is preferably in the range 1500-10000 Nl / (lh). The process of the present invention is an hourly catalyst m³Per 0.5 to 10 Kmol of olefin oxide produced, especially the hourly catalyst m³Per 0.7-8 Kmol of olefin oxide produced, eg m of catalyst per hour³It is preferable to carry out the work in the range of 5 Kmol of produced olefin oxide per unit. The working amount used here is the amount of olefin oxide produced per unit volume of the catalyst per hour, and the selectivity is the molar amount of olefin oxide produced relative to the molar amount of converted olefin. is there.

The produced olefin oxide is recovered from the reaction product by a method known in the art, such as absorbing the olefin oxide into water from the reactor outlet stream or, in some cases, recovering the olefin oxide from the aqueous solution by distillation. You may. At least a portion of the aqueous solution containing olefin oxide may be used in the next step to convert olefin oxide to 1,2-diol or 1,2-diol ether.

The olefin oxide produced in this epoxidation process may be converted to 1,2-diol or 1,2-diol ether. At the same time, the production of olefin oxides according to the present invention and the subsequent olefin oxides obtained are 1,2-diols and / or 1,2, as the present invention provides a more interesting process for the production of olefin oxides. -It will lead to more interesting processes, including its use in the production of diol ethers.

Conversions to 1,2-diols or 1,2-diol ethers include the proper use of acidic or basic catalysts to react olefin oxides with water. For example, to produce primarily 1,2-diols, and less 1,2-diol ethers, 10-fold molar excess of water and olefin oxides are acid-catalyzed in a liquid phase reaction based on the total reaction mixture. For example, in the presence of 0.5-1.0% w sulfuric acid, the reaction may be carried out at 50-70 ° C at 1 absolute bar, or in a gas phase reaction at 130-240 ° C, 20-40 absolute bar (bar absolute). ), Preferably, the reaction may be carried out in the absence of a catalyst. As the proportion of water decreases, the proportion of 1,2-diol ether in the reaction mixture increases. The 1,2-diol ethers produced in this manner may be diethers, tri-ethers, tetra-ethers or subsequent ethers. Another option, 1,2-diol ether, may be obtained by converting the olefin oxide with an alcohol, especially a primary alcohol such as methanol or ethanol, by substituting at least one portion of the water with the alcohol. 1,2-diols and 1,2-diol ethers are used in various industrial applications such as food, beverages, tobacco, cosmetics, thermoplastic polymers, curable resin systems, detergents, heat transfer systems and the like. Can be used.

Unless otherwise specified, organic compounds such as olefins, 1,2-diols, 1,2-diol ethers and reaction modifiers described herein are usually at most 40 carbon atoms, more usually at most. It shall have 20 carbon atoms, especially at most 10 carbon atoms, and more particularly at most 6 carbon atoms. The range of the number of carbon atoms (ie, the number of carbon atoms) defined herein shall include the number indicating the limit of the range.

The computer program products of the invention are recorded on computer-readable media and computer-readable media suitable for instructing data processing systems to perform calculations in connection with the processes of the invention. Contains computer-readable program code. In a preferred embodiment, the computer program product further comprises computer-readable program code recorded on computer-readable media suitable for instructing the data processing system to control the processes of the present invention. .. The computer-readable media may be readable by, for example, an optical system or a magnetic system. The computer program product may be in the form of a disk, which is a permanent component of the computer system of the present invention, or may be a disk that can be inserted into a computer system. Feed material control means may be configured such that they communicate with the computer system of the invention to facilitate control of process steps of the process of the invention.

The present invention will be described with reference to the following examples. (Example (virtual)) As shown in EP-A-266015, containing silver, rhenium, cesium, lithium and sulfur on α-alumina, theoretical selectivity S in new state₀A catalyst with a value of 93% is used in the following experiments. S₀The above values are selected extrapolated to zero oxygen conversion at reaction temperatures of 30% ethylene, 8% oxygen, 5% carbon dioxide, 1400 kPa, 260 ° C, respectively, within the gas spatiotemporal velocity range. Determined by measuring sex.

In the experiment, ethylene oxide is produced as follows. A 1 kg sample of catalyst is loaded into a tubular reactor consisting of stainless steel tubes. The tube is immersed in boiling kerosene containing a cooling jacket and its end is connected to the gas flow system. Adjust the inlet gas flow rate so that the hourly space velocity of the gas is 6800 Nl / (lh). The suction pressure shall be 2100 kPa (absolute pressure). The feedstock for the reactor is 28 mol% ethylene, 8 mol% oxygen, 3 mol% carbon dioxide, 0.5 mol% ethane, 3x10.^-4Ethyl chloride in molar% concentration, 0.5 x 10^-4Mole% concentration of ethylene dichloride, 1x10^-4Vinyl chloride with a molar% concentration, 2 x 10^-4It contains a mol% concentration of methyl chloride, and the rest of the feedstock is nitrogen. The reaction temperature is 250 ° C. Selectivity for ethylene oxide is optimal for chlorides. Value of Q (ie Q₁) Is (3 × 10)^-4×1+0.5×10^-4×2+1×10^-4×1+2×10^-4×1/3)/(28×1+0.5×85)=8.04×10^-6Will be.

At some point when the feedstock composition changes to the presence of ethylene at a concentration of 25 mol% and ethane at a concentration of 0.7 mol%, the concentration of other components remains constant except for ethyl chloride. It is maintained. Ethyl chloride concentration 4.1 x 10 to maintain selectivity at optimal levels^-4Adjust to mol%. After these changes, the value of Q (ie Q₂) Is (4.1 × 10)^-4×1+0.5×10^-4×2+1×10^-4×1+2×10^-4×1/3)/(25×1+0.7×85)=8.01×10^-6Will be.