JPH03153636A - Production of saturated hydrocarbon - Google Patents

Abstract

PURPOSE:To obtain a saturated hydrocarbon in high efficiency and at a low cost by purifying 5C fraction containing diolefin and monoolefin and halides as impurities with water or alkali water at high temperature under high pressure and then hydrogenating the saturated hydrocarbon in the presence of a catalyst. CONSTITUTION:5C fraction containing diolefin and monoolefin and halides (e.g. 1,3-pentadiene and cyclopentene) and halides as impurities is purified with water or alkali water (e.g. aqueous solution of NaOH) at 100-200 deg.C under 7-30atm. for 30 seconds to 30 minutes to remove the halides and then hydrogenated in the presence of a catalyst such as Pd or Pt at 40-200 deg.C under 5-40atm. to give a saturated hydrocarbon. Preremoval of the halides suppresses deterioration of hydrogenating catalyst and can prolong life of the catalyst. A residue which is obtained by subjecting a hydrocarbon mixture prepared by naphtha cracking to cationic polymerization and removing most of diolefins as a polymer is used as the 5C fraction of raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a method for producing saturated hydrocarbons. More specifically, the present invention relates to a new production method capable of producing saturated hydrocarbons with higher efficiency than C5 fractions containing diolefins and monoolefins.

(Conventional technology and its problems) Isoprene from the carbon fraction produced by naphtha decomposition, etc.
(2) Saturated hydrocarbons obtained by hydrogenating diolefins such as 3-pentadiene and monoolefins such as cyclopetene, 2-methyl-butene-1, and pentene-1 have been conventionally used as gasoline. On the other hand, in recent years, the use of cyclopentane as a diluent for fluorocarbons has attracted attention.
It is thought that this cyclopentane can be obtained by hydrogenating cyclopentene in the Cs fraction. In this way, methods to obtain saturated hydrocarbons by hydrogenating diolefins and monoolefins in the C5 fraction are being considered, but if they contain halides as impurities, the hydrogenation catalyst deteriorates significantly. However, there was a problem in that the hydrogenation catalyst had to be replaced frequently.

The above problems will be explained in detail below using the production of cyclopentane as a specific example.

The hydrocarbon mixture of the Cs fraction usually contains relatively large amounts of 1,3-pentadiene, in addition to cyclopentene, which can be converted to cyclopentane by hydrogenation. For this purpose, 1,3-pentadiene is first treated with a cationic polymerization catalyst such as aluminum chloride to polymerize the polymer, and then the polymer containing unreacted 1,3-pentadiene and cyclopentene is removed. The reaction recovery mixture is hydrogenated in the presence of a hydrogenation catalyst to hydrogenate cyclopentene to cyclopentane and 1,3-pentadiene to n-pentane. This hydrogenated product is distilled to recover cyclopentane as a high-boiling fraction.

In this case, inorganic halides derived from the cationic polymerization catalyst present in the recovered mixture cause deterioration of the hydrogenation catalyst, so these inorganic halides are usually removed by washing with water prior to the hydrogenation reaction. There is.

However, in reality, in such a method for producing cyclopentane, the deterioration of the hydrogenation catalyst is usually significant;
This lick 1 requires frequent hydrogenation catalyst replacement.
However, there were major constraints on improving the production efficiency of cyclopentane and reducing its production cost.

This invention was made based on the above circumstances, and it solves the drawbacks of the conventional method for producing saturated hydrocarbons from C5 fractions, and involves cationic polymerization of C9 fractions containing diolefins and monoolefins. , a new method for hydrogenating the recovered mixture after removing polymers, suppresses the deterioration of the hydrogenation catalyst, extends the catalyst life, and enables the production of saturated hydrocarbons with high efficiency and low cost. The purpose is to provide a method for producing saturated hydrocarbons.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is directed to a Cs fraction containing diolefins and monoolefins, and containing halides as impurities, by heating it with water or alkaline water at a high temperature. A method for producing saturated hydrocarbons is provided, which comprises washing under high pressure and then hydrogenating diolefins and monoolefins in the presence of a catalyst.

In this invention, inorganic halides still remain in the recovered mixture after normal polymerization treatment even after washing with water, and it has not been possible to completely remove them using conventional methods of washing with water. Furthermore, since organic halides are also present in the recovered mixture, in order to suppress deterioration of the hydrogenation catalyst and extend its life, it is necessary to completely remove these organic halides as well as the solid halides. Based on the knowledge that cleaning with water or alkaline water under high temperature and pressure is extremely effective in removing these halides and thereby extending the life of the catalyst, rather than the conventional simple water washing treatment. It was completed by

In the production method of the present invention, a C1 fraction hydrocarbon mixture, in particular a diolefin obtained by cationically polymerizing a hydrocarbon mixture obtained as a C5 fraction from ordinary naphtha cracking and removing most of the diolefin as a polymer; A C5 fraction containing monoolefins and halides as impurities is used as the target raw material.

In this case, the method for cationic polymerization of the hydrocarbon mixture and the method for removing the diolefin polymer can be handled in accordance with the conventionally known method disclosed in, for example, Japanese Patent Laid-Open No. 57-62227.

For example, hydrocarbons consisting of ~10% by weight of cyclopentane, 10-30% by weight of cyclopentene, 50-80% by weight of 1,3-pentadiene, and other C5 fractions produced when isoprene is extracted from the C5 fraction from naphtha cracking. The mixture is polymerized in the presence of a cationic polymerization catalyst, and the recovered mixture after removing the polymerized product is used as the raw material object of the present invention.

The cationic polymerization catalyst in this case is not particularly limited in its type, and for example, aluminum chloride, aluminum bromide, titanium tetrachloride, tin tetrachloride, ethylaluminum chloride, etc. are used.

Through this polymerization treatment, diolefins such as 1,3-pentadiene can be selectively polymerized and removed from the mixture as a polymerized product. Even when diolefins and acetylenes such as pentyne-1 and pentyne-2 are contained, these can be removed as polymers. Further, even when α-olefins such as pentene-1,2-methylbutene-1 are contained, a considerable amount thereof can be removed by polymerization.

On the other hand, cyclopentene is a cyclic internal olefin and has low cationic polymerizability among unsaturated hydrocarbons.
In this polymerization treatment method, even under conditions where 1,3-pentadiene and the like are consumed, almost no consumption can be achieved. Furthermore, cyclopentane, which is a saturated hydrocarbon, is not consumed, so by appropriately setting the polymerization conditions as described above, the concentration of cyclopentene or cyclopentane can be relatively increased significantly.

There is no particular restriction on the method for removing the polymer after cationic polymerization, and unreacted hydrocarbon components may be recovered through normal treatment steps. For example, after cationic polymerization, ammonia water, calcium hydroxide aqueous solution, sodium hydroxide It can be easily recovered by adding a catalyst deactivating material such as an aqueous solution and distilling off unreacted hydrocarbon components.

In the production method of the present invention, the C and fraction recovery mixture containing diolefins and monoolefins and containing halides as impurities is then treated with water or alkaline water in the production method of the present invention. Wash at high temperature and pressure.

In this case, either water or alkaline water can be used as the cleaning liquid, but in order to improve the removal rate of halides, N a OHlKOH, NH, O
It is preferable to use alkaline water consisting of an aqueous solution of H or the like, and the pH of these aqueous solutions is usually 8 to 13. Regarding the amount of these cleaning liquids to be used, it is advantageous that the weight ratio of the cleaning liquid to the hydrocarbon recovery mixture is usually 0.5 or more, more preferably 1 or more.

The cleaning temperature is usually 50 to 200°C, preferably 7
The temperature is 0 to 200°C2, more preferably 100 to 200°C. Further, the pressure during cleaning is 1 to 30K, preferably 5 to 30K, and more preferably 7 to 30K.

If the temperature during washing is less than 50° C., the removal rate of halides cannot be sufficiently increased, and the effect of extending the life of the hydrogenation catalyst will not be sufficient.

On the other hand, when the temperature exceeds 200'C, the pressure increases,
This is not preferred because it causes decomposition of hydrocarbons in the mixture.

Note that the cleaning time is usually several seconds to 1 hour, preferably 3
The time should be approximately 0 seconds to 30 minutes. The cleaning time can be appropriately set depending on the relationship between the temperature and pressure during cleaning.

There are no particular restrictions on the type or structure of the equipment for high-temperature, high-pressure cleaning of the C1 fraction recovery mixture under these conditions; for example, a stirred reactor, packed column reactor, line mixing tower, etc. may be used as appropriate. can do.

By washing with water or alkaline water under high temperature and high pressure in this manner, halides contained as impurities in the hydrocarbon recovery mixture can be removed with high efficiency.

The recovered mixture of the cleaning solution contains several tens of inorganic halides such as hydrogen halides)TI (mercuric nitrate solution method,
(Results of analysis by JIS-0102 method) Several hundred ppn of organic halides such as butyl halide were contained (results of analysis by Wickvolt method and gas chromatography method).

If the recovered mixture containing such halides as impurities is simply washed with water in the conventional manner, the inorganic halides can be reduced to 1) I), but they cannot be completely removed. Furthermore, organic halides can hardly be removed.

In order to extend the life of the hydrogenation catalyst and enable the production of saturated hydrocarbons with high efficiency and low cost, it is necessary to reduce the amount of inorganic halides to trace amounts and to reduce the amount of organic halides to several thousand.
It will be necessary to reduce it to below 111 rubels,
This is achieved for the first time by cleaning under high temperature and high pressure according to the present invention.

Furthermore, in the present invention, if necessary, a distillation treatment may be further performed after washing, so that the content of organic halides can be reduced to an extremely low concentration.

The distillation conditions can be, for example, a temperature of 50 to 150°C and a pressure of 0.1 to 5' depending on the composition and content of the organic halide remaining after washing.

In this invention, after removing inorganic halides and organic halides from the recovered mixture as described above,
Saturated hydrocarbons are obtained by hydrogenating the diolefin and monoolefin contained in the mixture in the presence of a catalyst as in the conventional method.

In the hydrogenation treatment, a mixture from which inorganic and organic halides have been removed is heated at a temperature of 40 to 200°C and a pressure of 5 to 40K in the presence of hydrogen and a catalyst based on a metal from group I of the periodic table, such as palladium, platinum, ruthenium, nickel, or cobalt. , by bringing the mixture into contact with hydrogen at a molar ratio of 1 to 20 and LH3V of 0.1 to 4 hr'. This turns diolefins and monoolefins into saturated hydrocarbons. For example, more than 95% of cyclopentene can be converted to cyclopentane, and 1,3-pentadiene can also be converted to n-
It becomes pentane.

Note that when the concentration of monoolefin in the mixture is low, the concentration of monoolefin may be increased by distillation prior to hydrogenation. This improves the efficiency of obtaining saturated hydrocarbons derived from monoolefin, such as cyclopentane. be able to. Furthermore, if the mixture contains components that inhibit the hydrogenation reaction, such as ammonium ions, it is preferable to remove these in advance by a conventional method.

By distilling the hydrogenated product after hydrogenation, desired components can be obtained with high purity. For example, when separating cyclopentane by distillation, since the boiling point difference between the components contained in the hydrogenated product is large (cyclopentane: 49°C, n-pentane: 36°C), high-boiling components are recovered by distillation using a conventional method. This can be easily done.

In addition, when obtaining highly pure cyclopentane, it may be distilled again and purified if necessary.

Hereinafter, this invention will be specifically explained based on examples.

Example 1 C of naphtha cracking consisting of the composition shown in Table 1 below containing cyclopentane, cyclopentene, 1,3-pentadiene, etc.
100 parts of the S fraction hydrocarbon mixture was cationically polymerized using 1 part of an aluminum chloride catalyst, and then neutralized by adding a mixed aqueous solution of aqueous ammonia and calcium hydroxide to deactivate the polymerization catalyst. The polymer and catalyst were removed by tttr filtration, and 25 parts of the organic layer solution was recovered. Table 2 shows the composition.

Table 1 Table 2 The collected organic layer solution was washed with a 1% sodium hydroxide solution at high temperature and pressure to remove inorganic halides and organic halides. In this case, the cleaning conditions are such that the amount of sodium hydroxide solution used is 1:1 to the organic layer solution.
The temperature was 100°C, the pressure was 25X, and the cleaning time was 8 minutes.

After washing, the contents of inorganic halides and organic halides were measured, and the removal rates of each were calculated, and the removal rates were 99% or more and 70%. Inorganic halides are reduced from 20 pI) to trace amounts, and organic halides are reduced from 300 pB to 90 pI).

The removal rate of the halide was measured in the same manner as above by varying the amount of sodium hydroxide solution used and the washing temperature for the organic layer solution. Table 3 shows the removal rate of organic halides.

This confirms that halides were effectively removed from the organic layer solutions of these Examples.

Example 2 Inorganic halides and organic halides were removed under washing conditions: the amount of sodium hydroxide solution used relative to the organic layer solution was 1=1, the temperature was 165° C., the pressure was 25 K, and the washing time was 10 minutes. When the concentrations of inorganic halides and organic halides in the organic layer solution after treatment were measured, as shown in Table 4, there was a trace amount of inorganic halides and 300 pl of organic halides.

Next, this RNI solution was brought into contact with hydrogen using a palladium-based hydrogenation catalyst under the conditions of a temperature of 150° C., a pressure of 25 K, a molar ratio of organic layer solution to hydrogen of 4, and a LH3V of 2 hr-'. Hydrogenation was carried out so that the hydrogenation rate of cyclopentene was 95%. The composition of 25 parts of hydrogenated material was as shown in Table 5. When the catalyst life in this case was measured, it was found to be 21
It was 50 hours. This confirms that cleaning at high temperature and high pressure prior to hydrogenation can extend the life of the catalyst.

After hydrogenation, the mixture was distilled to obtain 20 parts of cyclopentane as a distillate component with a boiling point of 49°C. The purity of cyclopentane is approximately 90%
Met.

Example 3 After washing the organic layer solution in the same manner as in Example 2, a distillation column with 3 OR plates was used, and a 0.5゜×70°C 1 column: bottom extraction ratio = 90:10, reflux ratio 5. When the concentrations of inorganic halides and organic halides were measured by distillation depending on the conditions, it was found that the inorganic halides were in trace amounts and the organic halides were 5 ppn.

Next, the recovered components were hydrogenated in the same manner as in Example 2, and the catalyst life was measured to be 3,250 hours.

The results are also shown in Table 2. This confirmed that cleaning at high temperature and high pressure and further distillation can significantly reduce the concentration of organic halides and further extend the life of the catalyst.

Comparative Example 1 When the concentrations of inorganic halides and organic halides were measured without washing the organic layer solution, the inorganic halides were 201) pl'''C'' and the organic halides were 760 ppm.

Further, when this organic layer solution was hydrogenated in the same manner as in Example 2 and the catalyst life was measured, it was only 115 hours.

The results are shown in Table 2. As a result, it was confirmed that the life of the catalyst would be extremely short if the fin-layered container was not cleaned at high temperature and high pressure prior to hydrogenation.

Comparative Example 2 The organic layer solution was stirred and washed with water for 30 minutes at room temperature and normal pressure, and the concentrations of inorganic halides and organic halides were measured, and the inorganic halides were found to be 4 ppn.
The amount of organic halides was 756 ppn''C''.

In addition, the water-washed organic layer solution was hydrogenated in the same manner as in Example 2,
When the catalyst life was measured, it was only 376 hours.

These results are shown in Table 2. This confirmed that washing with water prior to hydrogenation was insufficient to remove inorganic halides, and organic halides could hardly be removed, making it impossible to sufficiently extend the catalyst life.

(Effects of the Invention) According to the present invention, halides can be effectively removed from a C6 fraction recovery mixture containing diolefins and monoolefins and containing halides as impurities. It becomes possible to extend the lifespan.

It becomes possible to produce saturated hydrocarbons with high efficiency and at low cost.

Claims (3)

[Claims] (1) The C_5 fraction containing diolefins and monoolefins and containing halides as impurities is washed with water or alkaline water at high temperature and pressure, and then the diolefins and monoolefins are hydrogenated in the presence of a catalyst. A method for producing saturated hydrocarbons, characterized by: (2) Claim (1) wherein the diolefin is 1,3-pentadiene and the monoolefin is cyclopentene.
) The method for producing saturated hydrocarbons described in ). (3) A method for producing cyclopentane according to claim (2), in which cyclopentane is separated by distillation from the hydrogenated product.