JPS5843373B2 - Alkene Luinoseizouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves contacting an alkene mixture consisting primarily of non-terminal olefins with a disproportionation catalyst to obtain
It relates to a method for producing alkenes having 14 carbon atoms.

No. 3,726,938 describes a process for the production of alkenes having a disproportionation step combined with an oligomerization step and an isomerization step.

Here, the raw material supplied to the disproportionation step is mainly composed of non-terminal olefins.

The effluent from this disproportionation process is a low molecular olefin fraction,
It has been shown that the olefin fraction is separated into an intermediate olefin fraction and a high molecular olefin fraction, which are recovered as desired products.

It has also been shown that the low molecular weight olefin fraction and the high molecular weight olefin fraction can be reused, for example, in the oligomerization step and/or the isomerization step, which are the preceding steps of the process.

Now, without separating the desired alkenes from the effluent of the disproportionation zone, the alkenes having a predetermined number of carbon atoms produced in the disproportionation zone are directly sent to the isomerization zone for double bond transfer. , and it has been found that it may be advantageous to further disproportionate the alkenes obtained here with one or more higher alkenes.

According to this method, desired alkenes can be obtained without using a large area or expensive special separation equipment, especially a special distillation column, and without recycling large amounts of unconverted or unnecessary alkenes. Yield always increases significantly.

The present invention involves contacting a mixture based on non-terminal alkenes containing one or more alkenes having a higher number of carbon atoms than the target alkenes with a disproportionation catalyst.
A method for producing alkenes having 11 to 14 carbon atoms in the molecule, in which the raw material mixture also contains alkenes having fewer carbon atoms than the target alkenes, which are subjected to double bond isomerization and subsequent The present invention relates to a method characterized by increasing the yield of target C1□-C14 alkenes by subjecting them to disproportionation.

The mixture fed as raw alkene in the process of the invention consists primarily of non-terminal alkenes, i.e.
The internal alkenes are at least 50 moles, especially 70 moles or more.

The feedstock has an α-olefin content of at most 15 parts, preferably less than 10 parts.

Such feedstocks are in particular those obtained by dehydrogenation of the corresponding alkanes.

Particularly preferred substances are those containing as a main component a non-terminal alkene having 4 to 60 carbon atoms in one molecule,
Mixtures containing higher alkenes, for example up to the level of CaO-alkenes, can be used as well.

It is believed that it is desirable for the double bond in the raw alkene to be present at a specific internal position.

Depending on the number of carbon atoms in the starting alkene, the preferred position of the double bond may be any position in the alkene molecule.

For this reason, preferred raw materials are alkenes or alkene fractions, such as those obtained by oligomerizing ethylene and then double-bond isomerization of this oligomer.

This oligomerization can be carried out by methods known in the art, particularly in Japanese Patent Application No. 47-70095 (Japanese Unexamined Patent Publication No. 48-19
No. 504).

Although there is no problem even if the raw material mixture contains a small amount of branched alkenes, it is desirable that the mixture consists essentially only of linear alkenes.

The alkenes with the desired number of carbons present in the effluent from the first disproportionation zone are separated, the double bonds in the alkenes are relocated, and the internal olefins obtained from any source are then separated. It is also within the scope of the present invention to subject the resulting mixture to a second disproportionation treatment.

However, particularly with regard to separation equipment, greater benefits are usually obtained if at least an amount of the product obtained from the first disproportionation zone is directly subjected to a double bond isomerization reaction.

For this reason as well, it is preferable to adopt the operating method described later.

For the same reason, it is preferred that substantially the entire amount of the double bond isomerization reaction product is fed to the second disproportionation treatment.

"Substantially all" means 90% or more of the total product, and the process does not contain any bleeding.
) refers to substances that may contain small amounts of heavy substances that are removed by methods such as

In a preferred embodiment of the present invention, at least a portion of the total amount of products obtained in the second disproportionation reaction is further subjected to an isomerization treatment and a disproportionation treatment.

It has been confirmed that by doing so, the yield of the target alkene can be further increased.

In some cases, it is possible to further repeat the double bond isomerization treatment and the subsequent disproportionation treatment, but usually no better results can be obtained by repeating such treatments. Dew.

Double bond isomerization technology for alkenes has been known for a long time, and many catalysts that meet the objectives of the present invention are also known.

References regarding this technique include F. Asinger, “
Monoolefins Chemistry and
International J
Our own methods in 5yn
tbetic Organic Chemistry”,
Part 11A3, p97-112, November
er, 1969 and Part II, p405
~430, August, 1970.

and H. Dunning” Review of
01ef inI some r i za tio
n”Industrial and Engineer
ing Chemistry 45 (1953).

p 551 ff, etc.

A basic alkaline earth metal compound supported on a carrier is a preferred catalyst for the isomerization reaction because it enables the reaction to be carried out at a relatively low isomerization temperature. Among these, activated aluminas, such as gamma- Particularly preferred are basic salts of potassium or supported on eta-alumina.

These catalysts are also excellent in ease of regeneration.

The most preferred catalyst is potassium carbonate supported on gamma-alumina.

This technique is described in British Patent Application No. 33782/73.

Alkene disproportionation reactions, such as those carried out in the process of the present invention, have been published in various publications.

In addition to the above-mentioned U.S. Pat. No. 3,726,938, other references related to this technology include G.
Catalytic Reviews″3(1),
p37-60 (1969), etc.

Catalysts that can be used include supported molybdenum oxide catalysts, tungsten catalysts supported on silica, and rhenium catalysts supported on alumina.

In the case of rhenium oxide-containing catalysts, they are not always satisfactory because they tend to promote the formation of structural isomers unless used at very low temperatures.

This isomerization phenomenon is hardly observed or not detected at all when using catalysts containing molybdenum oxide.

In the case of this molybdenum oxide-containing catalyst, it also has the effect of highly promoting the disproportionation of higher alkenes, such as those having 25 or more carbon atoms in one molecule.

The most preferred catalyst is a catalyst system comprising molybdenum oxide supported on alumina and promoted with cobalt oxide.

Considering the ease with which various fractions can be recovered from the process system, it is usually advantageous to use solid catalysts;
However, one may consider using a homogeneous catalyst in the final disproportionation step.

One of the advantages of the process of the invention is that by selecting the catalysts for each step of the double bond isomerization and disproportionation process, both steps can be operated at the same or substantially the same reaction temperature. This means that heating and cooling at intermediate stages are not necessary.

When using potassium carbonate on alumina as the isomerization catalyst and molybdenum oxide/cobalt oxide/alumina as the disproportionation catalyst, the preferred reaction temperature is 60-250°C.
is within the range of

An additional advantage inherent in these catalysts is that their activation can also be carried out under the same or nearly the same conditions.

Activation is carried out at 350-700°C, especially at 500°C in the presence of nitrogen.
It is preferable to carry out in the range of -600 degreeC.

Double bond isomerization and disproportionation processes may be carried out using either a fluidized catalyst bed or a fixed catalyst bed.

In the case of fixed beds, the spacing between each bed is arbitrary.

However, if mixing of the isomerization catalyst and the disproportionation catalyst occurs, it will be disadvantageous for process operations, such as replacing a catalyst with decreased activity, so it is preferable to prevent this from occurring. .

According to a preferred embodiment of the invention, the double bond isomerization treatment and the disproportionation treatment are preferably carried out continuously using a combination of at least two consecutive fixed beds.

The product obtained from the final disproportionation step contains one or more alkene fractions, preferably from C6 to C20.
A range of fractions are recovered.

Alkenes formed depending on the type of raw material feed and process operating conditions are, for example, C8~C12s C10~
C engineering.

It is obtained as various fractions such as and C14 to C1B.

The production of alkenes in the Ctt to C14 range is particularly advantageous since they are important materials as raw materials for the production of microbially degradable synthetic detergents, chemical- and light-resistant alkyd resins, and the like.

Higher alkenes such as C14-C1B are also useful as lubricating oil additives and the like.

The invention is explained more specifically in the following examples.

Example 1 In order to illustrate the effects achieved according to the method of the invention, experiments were carried out for the production of Ctt-C14 alkenes using a feedstock consisting of a mixture of n-octene and n-icosene.

It will be appreciated that in actual commercial production typically a rather complex mixture of raw materials is used.

The isomerization catalyst used was prepared as follows = 0
．． Gamma alumina (specific surface area 350 m/!9s pore volume 0.42 length/g) in the range of 5 to 1.0 degrees Celsius is heated to 500°C.
for 2 hours in air and then mixed with an aqueous potassium carbonate solution in such an amount that the pores of the alumina were sufficiently filled with liquid.

The alumina thus impregnated was dried in air at 120° C. and 0.033 bar abs for 3 hours.

After activation, this catalyst has a concentration of 3.6 per gram of alumina.
■ Sodium compound with a weight ratio of 0.7, calculated as Na2O based on the atomic K and the total composition, 5i02
0.02 weight of silicon compound and F
It contained iron compounds of 0.025 weight factor calculated as e2O3.

A commercially available disproportionation catalyst extruded into a cylindrical shape (diameter 1.6 mm, length 4.8 mm)
5 m/g s pore volume 0.54 Tnl/El, bulk density 0.52 g/cr/L) were used.

Its composition is based on alumina: 15.7% by weight Mo
O3,3,0 weight φCoo, calculated as sulfate 0.
37 weight range of sulfur compounds and 0.02 as Na2O
It consisted of a large amount of sodium compounds.

Both catalysts were activated at 575° C. for 16 hours in a nitrogen stream (2.71b”, g-1 catalyst).

Raw material mixture of 1-octene and 1-icosene (molar ratio 4
:1) comprises four adjacent fixed beds, the first and third beds are isomerization catalyst beds, and the second and fourth beds are disproportionation catalyst beds, These were introduced into a cylindrical tube of diameter ICrIL such that they were aligned in the direction of flow.

4 g of catalyst was placed in each catalyst bed.

In the first catalyst bed, the 1-alkenes were isomerized to a mixture of non-terminal octenes and icosenes, and this mixture was sent to the second catalyst bed to undergo a disproportionation reaction.

The mixture thus obtained, particularly containing 011-C14 alkenes, is sent to a third catalyst bed and subjected to a double bond isomerization reaction, followed by a second disproportionation reaction in a fourth catalyst bed. Ta.

A Ctt to C14 fraction was recovered from the effluent thus obtained.

The results and other reaction conditions are shown in the table below.

Example■ A cylindrical reactor is equipped with 12 consecutive fixed beds, of which 2g of isomerization catalyst is placed in the first catalyst bed, the third catalyst bed, and the fifth catalyst bed. , the seventh catalyst bed, the ninth catalyst bed and the first catalyst bed each have 1.6 g of supported isomerization catalyst, and the second, fourth, sixth, eighth,
Another experiment was conducted in the same manner, except that 0.83 g of disproportionation catalyst was placed in each of the catalysts contained in the tenth and first catalyst beds.

Other conditions and results obtained are as shown in the table above.

It should be noted that the space velocities shown are based on the total catalyst amount and that very high space velocities per catalyst bed were employed in this experiment.

Example 1 (Comparative Example) Another experiment was conducted with a single isomerization catalyst bed adjacent to a single disproportionation catalyst bed in a reaction tube.

This disproportionation catalyst bed yielded a product containing a CII-C□4 fraction, which was analyzed.

According to the analysis results, in this experiment, no migration of double bonds occurred in the C11-C14 alkene fraction of the product from the first disproportionation reaction treatment step, and the second disproportionation treatment was also performed. There wasn't.

The results obtained are as shown in the table above.

Claims (1)

[Claims] 1. A mixture mainly composed of non-terminal alkenes containing one or more alkenes having more carbon atoms than the target alkenes is brought into contact with a disproportionation catalyst to form 11 to 14 alkenes in one molecule. A method for producing alkenes having carbon atoms of A method characterized by increasing the yield of target C11-CI4 alkenes.