The way the hydration of olefins

 

(57) Abstract:

The invention relates to a method of continuous hydration of ethylene, propylene or mixtures thereof with water in the vapor phase to the corresponding alcohols in the presence of salts heteroalicyclic as a catalyst at a molar ratio of water to olefin passing through the reactor, in the range of 0.1 to 3.0, an average hourly rate of gas supply water/olefin through the catalytic system 0,010 - 0.25 g/min/cm3concentrations of heteroalicyclic 5 to 60 wt.% from the total mass of the catalytic system, at a temperature of 150 - 350oC and a pressure ranging from 1000 to 25000 kPa. Use of the catalyst, deposited on a silicon substrate, with salt heteroalicyclic is a metal salt kremnipolimer or phospholipases acid containing not more than 4 mol cation of an alkali metal or 2 moles of the cation of the alkaline earth metal per 1 mol of heteroalicyclic, which is soluble in a polar solvent at a temperature below 40oWith, and the polar solvent means one or more representatives selected from the group comprising water, C1-C4aliphatic alcohols, C2-C5glycols or ketones, and unreacted OET process, as well as prolong the service life of the catalyst. 3 C.p. f-crystals.

The invention relates to a method for the hydration of olefins to alcohols using salt heteroalicyclic as a catalyst.

Hydration of olefins such as ethylene and propylene, to the corresponding alcohols by carrying out the hydration in the vapor phase using postinoculation of the catalyst, deposited on a substrate are well known. This method is described in many publications, including the methods which are proposed in GB-A-1570650, US 4808559, GB-A-1371905, US 4038211, US 4012452, GB-A-1476534, GB-A-1306141, US 3996338 and CAN-A-844004. In each of these early publications the nature of the used silicon substrate characterized by various parameters, including pore volume, specific surface area, resistance to crushing and the degree of purity of the substrate.

In some of the publications, in particular in GB-A-1281120 described methods of liquid-phase hydration of olefins using heteropolyanions catalyst. In addition, US 2173187 describes how the hydration of olefins in the vapor phase to the corresponding alcohols using as catalyst heteroalicyclic, complex anion which includes one element of group VI sub-group And the Intermittent is it. When the substrate is used, preferred, as indicated, is silica gel, though also lists and other siliceous substrates, such as silicic acid, Japanese acid clay, bentonite, diatomaceous earth and asbestos. Similarly, in JP-A-57-130935 described method of hydration of olefins using heteropolyanions catalyst deposited on activated carbon. Further, in the US 2608534 described heteroalicyclic deposited on the bulk of the inorganic oxide or a metal hydroxide, as a catalyst for a number of common organic reactions, including, without limitation, the hydration of olefins. Among the substrates described in this publication are mentioned aluminum oxide, magnesium oxide, thorium dioxide, titanium dioxide and so on, and, as noted, the preferred aluminum oxide.

One of the problems that arises when using free heteropolyacids as catalysts for the hydration of olefins such as ethylene and propylene, to the corresponding alcohols, is that these catalysts are characterized by a high reactivity and the reactions tend to become highly exothermic, resulting in the danger of beginning and carrying out this reaction the moat good performance occur only during the reaction in a single pass. Usually, however, the conversion of ethylene in a single pass is only about 6%. Thus, when carrying out the process on an industrial scale unreacted ethylene must be returned to the reactor. If, nevertheless, free heterophilically the catalyst used during the continuous process, which includes the return of the unreacted olefin in the hydration reactor in order to maximize the utilization of the olefinic starting material, traces of impurities, such as aldehydes, ethers, some alcohol and some dimers/polymers of olefin present in such return in the process, the olefin, tend to significant deactivation or destruction of the catalyst. In addition, although in some previous publications for the reaction of hydration of the olefin, it is recommended to use certain salts of heteropolyacids, none of these are recommended to be applied salts cannot be called readily soluble at room temperature in readily available solvents, in most cases due to the high concentration contained in the salt cations, for example 6-12 moles of potassium per mole of heteroalicyclic that have a reverse effect on her rastvoriteli of olefin, which provides a return unreacted olefin in the hydration reactor. Thus, the description of any particular salt heteroalicyclic as a catalyst for concrete continuous process of hydration of olefins to the corresponding alcohols, the use of which reduces the above problems, is still missing.

It was found that this method can be improved by the use as catalysts of particular salts of heteropolyacids, which have variable activity, and further improve the creation of specific process conditions.

Thus, the invention proposes a method of continuous hydration of olefins with water in the vapor phase to the corresponding alcohols in the presence of salts heteroalicyclic as a catalyst, and the method includes returning the unreacted olefin in the reaction of hydration. This method differs in that the salt of heteroalicyclic is a metal salt kremnipolimer acid or phospholipases acid, which is soluble in the polar solvent at a temperature below 40oC, and as the metal in this sourceposition" means kremnipolymer acid or postovulatory acid together with all of crystallization water or without it.

In this case, and throughout the description the term "polar solvent" refers to one or more representatives from the group comprising water, lower aliphatic alcohols (for example, C1-C4alcohol), glycols (for example, C1-C4glycols) and ketones (such as acetone or methyl ethyl ketone).

Acceptable catalyst contains not more than four moles of the cation of an alkali metal or two moles of the cation of the alkaline earth metal per mole of heteroalicyclic, preferably the salt of heteroalicyclic contains from one to two monovalent cations. Thus, the preferred one - or Duklja salt. The catalyst is advisable to put on a silicon substrate, and further deposited on the catalyst substrate is called "catalytic system". Specific examples of such substrates include silica or synthetic silica, prepared, for example, from Smoking silica or by hydrolysis in the flame of silicon tetrachloride. The substrate may be in any acceptable physical form, such as granules, tablets or extrudates. Silica such varieties are available as proprietary products firms Grace and Degussa (relevant to the LCD with a solution of salt of heteroalicyclic, which in turn is prepared by dissolving salts heteroalicyclic in a solvent such as, for example, alcohol or distilled water. Then, in the thus prepared solution is injected substrate. The substrate is advisable to leave for impregnation in a solution of salt of heteroalicyclic for several hours with periodic mixing by hand, and after this time it is recommended to filter using a Buchner funnel to remove all the excess salt acid. You can also use another method of impregnation, such as the method of initial moisture content.

Next, the thus prepared wet catalyst supported on a carrier, it is advisable to put in a drying Cabinet in which it is maintained at elevated temperature for several hours for drying, and after this time it is allowed to cool to room temperature in a desiccator. The weight of the catalyst is dried, is determined by subtracting the mass of the used substrate from the weight of the catalyst on the substrate, and from these data it is possible to calculate the content of catalyst in grams per liter. This catalyst (amount measured by weight) is then used in the corresponding process, such as, for example and, therefore, on its activity. Thus, it is possible that either impregnation or the process of hydration of the olefin or both can change the degree of hydration and oxidation state of the metal salts of heteropolyacids, i.e. in terms of the process state of hydration/oxidation of metals actual catalytic fragments in salts of heteropolyacids, which were used for impregnation of the substrate, can not be maintained. Therefore, it is natural to expect that the spent catalysts after the reaction can also be in various States of hydration and oxidation. Applied to the catalyst substrate in the form of salts heteroalicyclic (catalytic system can also be modified by adding phosphoric acid or other mineral acids.

This way it is advisable to create the following reaction conditions:

a) the recommended value is the molar ratio between water and olefin passing through the reactor is in the range of 0.1 to 3.0, preferably 0.1 to 1.0,

b) the recommended average hourly feed rate of the gas (SCSP) mixture of water/olefin is 0,010-0.25 g/min/cm3the catalytic system, predpochtite is 5-60 wt.% in terms of the total weight of the catalytic system, preferably 5-40 wt. % and most preferably 10-30 wt.% in terms of the total weight of the catalytic system.

The hydration reaction of olefins is carried out at a temperature of 150-350oC. In this temperature interval the hydration of ethylene to ethanol expediently carried out at a temperature in the range from the dew point of up to 350oC, preferably from 200 to 300oWith; the hydration of propylene to isopropanol expediently carried out at a temperature in the range from the dew point up to 300oC, preferably at 150-250oC.

Acceptable olefins subjected to hydration, are ethylene and propylene, and the corresponding alcohols formed are respectively ethanol and isopropanol. These olefins can be used in pure form or in the form of a mixture of olefins with obtaining the appropriate mixture of alcohols. Thus, this purpose can be used mixed hydrocarbon raw materials (withdrawn, for example, from the plant for processing oil, such as used in the catalytic cracking fluid), which is a mixture of saturated and unsaturated fatty 2-C3of hydrocarbons. This process is carried out in the vapor phase, i.e., tion of the gaseous reagents, which dissolves in the catalytic system. I believe that the hydration reaction proceeds between the dissolved reagents. During this reaction as by-products are formed ethers corresponding to the olefin. The proposed method further improve and optimize the return unreacted olefin in the reactor after removal, if necessary, undesirable impurities.

The hydration reaction is conducted by introducing the catalytic system in the reactor, closing the reactor and then heating the catalytic system to the reaction temperature. Depending on the target end-product of the catalytic system is heated to a temperature of 150-300oC. for example, if the end product is ethanol derived from ethylene, a catalytic system suitable to heat up to 200-280oWith, preferably 200-260oS, more preferably 210-245oC. on the other hand, when the end product is isopropanol derived from propylene, the catalytic system suitable heated to a temperature in the range from slightly above the dew point to 225oWith or preferably to a temperature in the range from several pre is via the reactor in the vapor miss a portion of the olefin and water. The recommended value of the molar ratio between water and olefin flowing through the reactor is in the range of 0.1 to 3.0, preferably 0.1 to 1.0, more preferably from 0.25 to 0.45. The volumetric rate of feed of the mixture of steam/olefin passing through the reactor, can slightly vary depending on whether the olefinic reactant ethylene or propylene. For example, in the case of ethylene featured volumetric feed rate its mixture with water vapor is 0,010-0,100, preferably 0,020-0,050 g/min/cm3the catalytic system. In the case of a mixture of propylene with water vapor recommended volumetric rate equal 0,010-0,100, preferably of 0.02-0.07 g/min/cm3the catalytic system.

The hydration reaction is carried out under a pressure in the range of 1000-25000 kPa. In this range, the hydration reaction of ethylene recommended pressure 3000-10000 kPa, while the hydration of propylene recommended pressure 2000-7600 kPa.

The formation of alcohol and diethyl ether was determined by gas chromatography (see below), whereas the unreacted olefin was determined by measurement using a wetted flow meter pressure type.

Activity is nocatalog period in standard test conditions, and unreacted olefin (as outlined in the examples below).

Thus, it was established that the use of this particular catalytic system presented in the present description, makes it possible not only to increase the volumetric productivity ("ODA") and the selectivity of the process, but also prolong the service life of the catalyst/substrate, which reduces the frequency with which the installation replace the catalyst/substrate.

Below the invention is illustrated in the examples.

EXAMPLE 1

Preparation of catalyst

370 g 12-wolframtones acid HN2About (x 24) was dissolved in 800 ml of distilled water to which was added 1,488 g of orthophosphoric acid (fortress 85 %). In a separate vessel in 50 ml of water was dissolved of 11.15 g knso3and then stirring was slowly added to the acid solution. This vessel was three times washed with 50 ml of distilled water (total, used 150 ml) and the washing water was added to the acid solution (the number of knso3was chosen so that one molar equivalent of potassium accounted for 12 mol-wolframtones acid HN2Oh, dissolved in this solution). After the dog 57, almost pure kremmidiotis media (> and 99.8 wt.% silicon dioxide) and left imbued within 24 hours After impregnation of the catalyst within 1 h were trenirovki excess solution, and then dried in air at 105oC for 16 h, the Mass of one liter of the finished catalyst was 551 g, so that the acid content was equal to 151 g/l

Process

In an installation that used the return process (unreacted) ethylene, before serving in the gas-liquid high pressure separator, used to separate the enriched water and enriched with ethylene phases, gaseous product leaving the reactor was cooled to 20oWith the refrigerator high pressure. Rich in water phase, which contained the bulk-derived ethanol, and diethyl ether and acetaldehyde as a by-product through the control valve under normal pressure directed into the collection. Next, rich in ethylene stream from the gas-liquid separator was sent to the base of the tower for washing water, where he was faced with moving countercurrent water, which from the rising gas stream removed the bulk of the remaining ethanol. After that oceanologia ether, 5 mg/l of acetaldehyde and less than 0.5 mg of ethanol per liter of gas (as defined in the conditions of normal temperature and pressure), was filed in the recirculation device for re-entry into the reactor. The flow rate of water in the tower for washing water was approximately 1300 ml/h, and its level in the tower was supported by system level control and regulating valve to drain the fluids. The liquid withdrawn from the tower for washing, mixed with the liquid product withdrawn from the gas-liquid separator and including the ethanol.

Conditions

The reactor was loaded one liter of catalyst (concentration of acid 151 g/l), prepared according to example 1. After you enable the installation was injected ethylene and process conditions brought up to the target and stabilized. The inlet pressure in the reactor was 6980 kPa, the temperature at the inlet of the reactor was equal to 225,1oTemperatures at the outlet of the reactor was equal to 245.6oWith the flow rate of the ethylene returned to the process, was 1500 g/h, the value of the molar ratio of water/ethylene entering the reactor was 0,387, the flow rate of water, which flowed at a room temperature of 21oWith (preferably 20-30oC), V has achieved the following performance results: performance on ethanol 163,5 (ODA), diethyl ether 7,02 (ODA), the acetic aldehyde 0,60 (ODA), the selectivity for ethanol 94,6% (selectivity is defined as the ratio between the number of moles of ethylene converted into ethanol, and the total number of moles of ethylene converted into different products).

Comparative test (not according to invention)

The following experiment was carried out similarly to example 1, but in the setting in which unreacted ethylene was not returned to the reactor. The results received in the plant, including the reactor, which contained 50 ml of a catalyst similar to the catalyst of example 1, in isothermal conditions and for comparison with the volume of catalyst in example 1, the parameters were multiplied by a factor of 20.

The inlet pressure in the reactor was 4825 kPa, the temperature at the inlet of the reactor was equal to 235,0oWith the flow rate of ethylene was 1440 g/h, and the value of the molar ratio of water/ethylene entering the reactor was equal to 0.30.

In the pilot plant using the catalyst of this comparative tests have achieved the following performance results: performance on ethanol 97 (ODA), diethyl ether 163 (ODA), the acetic aldehyde 7,2 (ODA), ASS="ptx2">

1. Method for continuous hydration of ethylene, propylene or mixtures thereof with water in the vapor phase to the corresponding alcohols in the presence of salts heteroalicyclic as a catalyst at a molar ratio of water to olefin passing through the reactor, in the range from 0.1 to 3.0, an average hourly rate of gas supply water/olefin through the catalytic system from 0,010 to 0.25 g(min. cm3), the concentration of heteroalicyclic from 5 to 60 % by weight of the total catalytic system, at 150 - 350C and a pressure of 1000 - 25000 kPa, characterized in that the use of the catalyst, deposited on a silicon substrate, with salt heteroalicyclic is a metal salt kremnipolimer acid or phospholipases acid containing not more than 4 mol cation of an alkali metal or 2 mol of cations of alkaline-earth metal per 1 mol of heteroalicyclic, which is soluble in a polar solvent at a temperature below 40C, and the polar solvent means one or more representatives selected from the group comprising water, C1-C4aliphatic alcohols2-C5glycols or ketones, and unreacted olefin return in the hydration reaction.

2. The method according to p. 1, in which katalysatoren, and the hydration reaction is carried out at 200-300C.

4. The method according to p. 1 or 2 in which the olefin is a propylene, and the hydration reaction is carried out at 150-C.

 

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