JP2013203704A - Method of producing olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a long-chain olefin within a short reaction time in high yield in a dehydration reaction of a long-chain aliphatic alcohol.SOLUTION: In a method of producing an olefin, a dehydration reaction of an alcohol is carried out in the presence of a catalyst wherein at least one selected from a phosphoric acid, a phosphate or a condensate of them is carried by a titanium oxide.

Description

  The present invention relates to a method for producing an olefin, and more particularly to a method for producing a long-chain olefin by a dehydration reaction of a long-chain aliphatic primary alcohol.

Various methods are known as a method for producing an olefin compound by dehydration reaction of alcohol. For example, a method for producing an olefin compound by dehydration reaction of alcohol in a gas phase is known. Here, the gas phase reaction means a reaction at a boiling point or higher of the raw material alcohol.
Patent Document 1 discloses a method for producing an olefin compound by dehydration reaction of a secondary alcohol in a gas phase at a reaction temperature of 300 to 400 ° C. in the presence of zirconium oxide. In Patent Document 2, primary alcohol or ether is used as a raw material, and the reaction temperature is set within a range of 150 to 350 ° C. so that the reaction is performed under gas phase conditions. A method for producing an α-olefin which performs a gas phase elimination reaction using a catalyst is disclosed.

  On the other hand, the present inventors can obtain olefins in a short time and in a high yield while suppressing energy consumption by conducting a liquid phase dehydration reaction of a long-chain alcohol using a catalyst having a specific weak acid point. And have filed a patent application first (see Patent Document 3).

JP 61-53230 A JP 2003-95994 A International Publication No. 2011/052732

  However, in the gas phase reaction represented by the methods described in Patent Documents 1 and 2, it is necessary to vaporize all of the raw materials, and particularly for long-chain aliphatic alcohols having a high boiling point, energy consumption is large and costly. Is also disadvantageous. Furthermore, olefination under high-temperature conditions tends to cause both branching by alkyl rearrangement and olefin quantification, resulting in a problem of reduced product yield.

The olefin obtained by the method described in Patent Document 3 has few by-products due to multimerization, branching, etc., and is useful as a raw material for oils and surfactants, but when used as a surfactant, In addition to those having a double bond at the end of the alkyl chain, those having a double bond inside the alkyl chain (parts other than the end of the alkyl chain) are required from the functional aspects such as solubility and emulsification characteristics. Yes.
The present invention provides a method for producing a long-chain olefin in a high yield in a short reaction time in a dehydration reaction of a long-chain aliphatic alcohol, and in particular, a double bond is isomerized inside an alkyl chain. A production method capable of efficiently producing a long-chain olefin is provided.

  The present inventor found that when a dehydration reaction of a long-chain aliphatic alcohol was performed in the presence of a specific catalyst, the reaction proceeded rapidly and a long-chain olefin was obtained in a high yield. That is, the present invention is a method for producing an olefin in which a dehydration reaction of an alcohol is performed in the presence of a catalyst in which at least one selected from phosphoric acid, a phosphate, and a condensate thereof is supported on titanium oxide.

  The present invention provides a method for producing a long-chain olefin in a high yield in a short reaction time in a dehydration reaction of a long-chain aliphatic alcohol, and in particular, a double bond is isomerized inside an alkyl chain. Long chain olefins can be produced efficiently.

  The method for producing an olefin of the present invention is selected from the dehydration reaction of a long-chain alcohol from titanium oxide to phosphoric acid, a phosphate, and a condensate thereof (hereinafter sometimes abbreviated as “phosphoric acid etc.”). The reaction is carried out in the presence of a catalyst supporting at least one kind.

[catalyst]
In the production method of the present invention, a catalyst in which phosphoric acid or the like is supported on titanium oxide is used as a catalyst. In this specification, the term “supported” means bonding by physical and / or chemical bonding force to titanium oxide.
The catalyst used in the present invention is one in which at least one of phosphoric acid and its condensate, phosphate and its condensate is supported on titanium oxide, and phosphoric acid, phosphate and their condensation. It is also possible to carry a mixture of products.
Here, the phosphoric acid condensate includes pyrophosphoric acid, polyphosphoric acid, phosphoric anhydride, and the like, which are produced by condensation in the firing process after the phosphoric acid is supported. Similarly, phosphate condensates include pyrophosphates, polyphosphates, and the like, which are formed by condensation of phosphates having one or two hydrogens in the firing process after loading. In the present invention, from the viewpoint of improving the reaction rate, it is preferable to use a catalyst in which phosphoric acid and / or a condensate thereof are supported on titanium oxide.

The phosphate is preferably a soluble phosphate from the viewpoint of ease of catalyst preparation, and is preferably a partially neutralized salt of an alkali metal or alkaline earth metal. Specific examples of such phosphates include magnesium monohydrogen phosphate (MgHPO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), sodium phosphate (Na _3). PO ₄ ), sodium pyrophosphate (Na ₄ P ₂ O ₇ ), disodium dihydrogen pyrophosphate (Na ₂ H ₂ P ₂ O ₇ ), sodium tripolyphosphate (Na ₅ P ₃ O ₁₀ ), sodium tetrapolyphosphate ( Na ₆ P ₄ O ₁₃ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ), potassium phosphate (K ₃ PO ₄ ), etc. From the viewpoints of improving the reaction rate and yield, magnesium monohydrogen phosphate is preferred.

The catalyst used in the present invention can be prepared by a so-called impregnation method. As a specific preparation method, an aqueous suspension or aqueous solid of titanium oxide and an aqueous solution of phosphoric acid and / or phosphate are mixed to prepare an impregnated product, and the obtained impregnated product is dried and fired. The method of doing is mentioned.
Titanium oxide serving as a carrier can be obtained, for example, by hydrolyzing a soluble precursor such as titanium alkoxide, titanium tetrachloride, or titanyl sulfate in a water-containing solvent. The titanium oxide support thus obtained has a high content of titanium hydroxide and can be used in the next impregnation step as a slurry, or can be made into a cake by filtration, centrifugation, etc., and further dried. What was baked and made into the solid can also be used. As the titanium oxide carrier, it is preferable to use titanium oxide having a high content of titanium hydroxide obtained by hydrolyzing a soluble precursor without drying and baking.

In addition to the method of impregnating and supporting phosphoric acid itself, titanium oxide supporting phosphoric acid or a condensate thereof is phosphoric acid using ammonium such as diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ) as a counter ion. It can also be obtained by a method of impregnating and supporting a salt and then evaporating or decomposing counter ions by drying and baking. In this method, a salt such as ((NH ₄ ) ₂ HPO ₄ ) may remain on the baked titanium oxide.

The temperature at which the phosphoric acid and phosphate are impregnated with titanium oxide is preferably 0 to 100 ° C, more preferably 20 to 95 ° C, and more preferably 50 to 90 ° C, from the viewpoint of the carrying rate and the uniformity of the resulting catalyst. Further preferred. The impregnation time is preferably 0.1 to 10 hours, more preferably 0.2 to 5 hours, and further preferably 0.5 to 2 hours.
The firing temperature after impregnation is preferably 200 to 1000 ° C, more preferably 300 to 800 ° C, and still more preferably 400 to 600 ° C. The firing time is usually 1 to 10 hours.
Since the catalyst thus obtained is in an agglomerated state, it can be appropriately pulverized into powder, granules, or formed into noodles, pellets, or the like.
The cake in the present invention is obtained by hydrolyzing titanium alkoxide and then separating and removing a part or all of the liquid by a separating means such as centrifugal separation.

  The supported amount of at least one selected from the phosphoric acid, phosphate, and condensates thereof is preferably 1 to 50 mass%, more preferably 5 to 50 mass%, and more preferably 15 to 50 mass% of titanium oxide. Further preferred. When the ratio of phosphoric acid and the like is within the above range, the reaction can be completed in a short time.

  1-60 mass% is preferable with respect to raw material alcohol, and, as for the usage-amount of a catalyst, 2-40 mass% is more preferable, and 3-20 mass% is still more preferable. When the amount of the catalyst used is within the above range, the reaction temperature can be kept low, which is economical.

  Although the details of the reaction mechanism when the catalyst is used are not clarified, it is considered that the reaction proceeds as follows. That is, in addition to the Lewis acid point on titanium oxide, the supported phosphate group functions as a Bronsted acid, and the concerted effects enhance alcohol dehydration activity and olefin isomerization activity. it is conceivable that.

[Raw alcohol]
The alcohol used as a raw material in the present invention is preferably an aliphatic primary alcohol having 12 to 24 carbon atoms, more preferably 14 to 20 carbon atoms, and still more preferably 16 to 18 carbon atoms.
Specific examples of the raw material alcohol include 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, Examples include 1-eicosanol.
These raw material alcohols may be used alone or in a combination of two or more.

[Organic solvent]
In the production method of the present invention, an organic solvent may be used as necessary. The organic solvent that can be used in the present invention is not particularly limited as long as it is liquid at the reaction temperature, is compatible with the substrate and the product, and does not inhibit the reaction, and may be a mixture. Moreover, what can isolate | separate from a product using a boiling point difference after reaction is preferable.
As the organic solvent that can be used in the present invention, hydrocarbon-based organic solvents such as saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, and aromatic hydrocarbons are preferable.

The saturated aliphatic hydrocarbon may be linear, branched or cyclic.
Specific examples of the saturated aliphatic hydrocarbon include compounds having 10 to 35 carbon atoms such as tridecane, hexadecane, octadecane, eicosane, docosane, triacontane, squalane and the like.
The saturated aliphatic hydrocarbon may be a mixture such as liquid paraffin, naphthene hydrocarbon, and isoparaffin hydrocarbon. Moreover, what is solid at normal temperature but liquid at the reaction temperature, such as solid paraffin, can also be used.
In addition, as the saturated aliphatic hydrocarbon, oligomers such as propylene and isobutene can be used.

The unsaturated aliphatic hydrocarbon may be linear, branched or cyclic.
Specific examples of the unsaturated aliphatic hydrocarbon include compounds having 15 to 35 carbon atoms such as eicosene, heicosene, dococene, tricosene, and squalene. The unsaturated aliphatic hydrocarbon may be a mixture.

  Specific examples of the aromatic hydrocarbon include alkylbenzene and alkylnaphthalene such as n-dodecylbenzene, n-tridecylbenzene, n-tetradecylbenzene, n-pentadecylbenzene, n-hexadecylbenzene, diisopropylnaphthalene and the like. .

[Dehydration reaction (olefination reaction)]
The reaction in the method of the present invention is a dehydration reaction of alcohol, and if the by-produced water stays in the system, the reaction rate may decrease. Therefore, from the viewpoint of improving the reaction rate, an inert gas such as nitrogen or argon is introduced into the reaction system under stirring, usually under a reduced pressure of about 0.03 to 0.09 MPa or at normal pressure, and the generated water is discharged outside the system. It is preferable to carry out the reaction while removing it.
The reaction temperature is not higher than the boiling point of the raw alcohol from the viewpoint of reaction rate and suppression of side reactions such as alkyl rearrangement and multimerization, preferably 200 to 300 ° C, more preferably 230 to 300 ° C, and 250 to 290 ° C. Is more preferable, and 260-280 degreeC is still more preferable.

  In the present invention, the olefination reaction is preferably a liquid phase reaction. The liquid phase reaction refers to a reaction below the boiling point of the raw alcohol, that is, below the temperature at which the liquid phase exists. In the case of a liquid phase reaction, it is not necessary to vaporize all the raw materials, so that the manufacturing cost can be suppressed. In addition, branching due to alkyl rearrangement and olefin multimerization can be suppressed, so that the desired product can be obtained in high yield.

  The reaction time is preferably such that the alcohol reaction rate is preferably 95% or more, more preferably 97% or more, and still more preferably 98% or more, from the viewpoint of the yield of the desired olefin. Such reaction time may vary depending on the reaction temperature, the type of organic solvent, the type of catalyst and the amount used, etc., but in a suspension bed batch reaction, preferably 0.1 to 20 hours, more preferably 0.5 to 10 hours, more preferably 1 to 7 hours. In the fixed bed reaction, LHSV (liquid space velocity) is preferably 0.1 to 5.0 / h, more preferably 0.2 to 3.5 / h, and still more preferably 0.3 to 2.0 / h.

According to the production method of the present invention, the alcohol reaction rate is usually 80% or more, preferably 90% or more, and the yield of olefin is usually 90% or more. Moreover, the production | generation rate of the branched olefin and dimerization body which are contained in olefin becomes normally 5% or less, respectively.
Furthermore, the olefin obtained by the production method of the present invention has a high ratio of those internally isomerized, and those having 30% or more of all olefins internally isomerized can be easily obtained.

  In the present invention, only the olefin may be purified by distillation from the reaction product obtained as described above. Highly purified olefins obtained by distillation purification are useful as raw materials or intermediate raw materials for surfactants, organic solvents, softeners, sizing agents and the like.

<1> A method for producing an olefin in which a dehydration reaction of an alcohol is performed in the presence of a catalyst in which at least one selected from phosphoric acid, a phosphate, and a condensate thereof is supported on titanium oxide.
<2> The method for producing an olefin according to <1>, wherein the catalyst is obtained by supporting at least phosphoric acid and / or a condensate thereof on titanium oxide.
<3> The alcohol is a primary alcohol having 12 to 24 carbon atoms, more preferably 14 to 20 carbon atoms, still more preferably an aliphatic primary alcohol having 16 to 18 carbon atoms, specifically 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, 1-eicosanol, etc. The method for producing an olefin according to <1> or <2>, which is at least one kind.

<4> The dehydration reaction is performed at 200 to 300 ° C., preferably 230 to 300 ° C., more preferably 250 to 290 ° C., and still more preferably 260 to 280 ° C., according to any one of <1> to <3> Of producing olefins.
<5> The method for producing an olefin according to any one of <1> to <4>, wherein the dehydration reaction is performed in a liquid phase.
<6> The supported amount of at least one selected from the phosphoric acid, phosphate, and condensates thereof is preferably 5 to 50% by mass, more preferably 15 to 50% by mass of the mass of titanium oxide. The method for producing an olefin according to any one of <1> to <5>.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
Example 1
<Preparation of catalyst>
The catalyst used in Example 1 was prepared by the following method. That is, 71 g of titanium isopropoxide and 800 g of ethanol were mixed, and 600 g of ion-exchanged water was added dropwise thereto at room temperature over 1 hour, followed by stirring at room temperature for 1 hour. The resulting precipitate was then filtered to make a titanium hydroxide cake. To this titanium hydroxide cake, 1.3 g of diammonium hydrogen phosphate and 200 g of ion-exchanged water are added, and heated and stirred with an evaporator (60 ° C.), whereby diammonium hydrogen phosphate and Impregnated with ion exchange water. The impregnated material was dried at 120 ° C. for 12 hours and then calcined at 500 ° C. for 3 hours, and used as a catalyst. The catalyst obtained by this method is one in which phosphoric acid is supported as a main component on titanium oxide.

<Manufacture of olefins>
In a flask equipped with a stirrer, 15.0-octadecanol (trade name: Calcoal 8098, manufactured by Kao Corporation, boiling point: 336 ° C.) 25.0 g (0.19 mol), catalyst (phosphoric acid or its condensate into titanium dioxide) 0.75 g (3.0% by mass with respect to the raw material alcohol)) of 5% by mass supported (phosphoric acid amount = 5% by mass)) is charged, and nitrogen is circulated in the system at 280 ° C. with stirring. (Nitrogen flow rate: 50 mL / min) for 5 hours.

  The solution after completion of the reaction was diluted with hexane, and then a gas chromatograph analyzer (trade name: HP6890, manufactured by HEWLETT PACKARD), [Column: Ultra ALLOY-1 capillary column 30.0 m × 250 μm (trade name, Frontier Laboratories, Inc.) Product), detector: hydrogen flame ion detector (FID), injection temperature: 300 ° C., detector temperature: 350 ° C., He flow rate: 4.6 mL / min], and the product was quantified. The results are shown in Table 1.

In addition, the alcohol reaction rate, the olefin yield, and the olefin selectivity (internal / terminal) were calculated by the following formulas.
Alcohol reaction rate (%) = 100- [residual alcohol amount (mol) / raw material alcohol charge amount (mol)] × 100
Olefin yield (%) = [Olefin amount (mol) / Feed amount of raw material alcohol (mol)] × 100
Olefin selectivity (internal / terminal ratio) = internal olefin selectivity / terminal olefin selectivity dimer production rate (%) = [dimer olefin amount (mol) / raw alcohol charge (mol)] × 100
The reaction conditions and results are summarized in Table 1.

Comparative Examples 1-7
The reaction was carried out in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1, and the products were analyzed. The reaction conditions and results are summarized in Table 1. In addition, Comparative Examples 1, 3, 5, and 7 each use a metal oxide that does not carry phosphoric acid or its condensate as a catalyst, and Comparative Examples 2, 4, and 6 correspond to titanium alkoxides, respectively. Instead of the metal alkoxide, a catalyst was prepared by the same method as the catalyst preparation method described in Example 1. The results are shown in Table 1.

  From the results of Table 1, it can be seen that when titanium oxide is used as the metal oxide, a specifically high reaction rate and high internal isomerization rate can be obtained.

Examples 2-6
The reaction was carried out in the same manner as in Example 1 except that the loading amount of phosphoric acid (phosphoric acid amount) and the reaction temperature were changed as shown in Table 2. The results are shown in Table 2.

  As is apparent from Table 2, when the amount of phosphoric acid and the like supported is large, the production ratio of internal olefin is high.

Examples 7 and 8
Example 7 was the same as in Example 5 except that the amount of catalyst, reaction temperature and reaction time were changed as shown in Table 3. Further, Example 8 was subjected to the reaction in the same manner as Example 7 except that the raw material alcohol and the reaction temperature were changed as shown in Table 3. The results are shown in Table 3.

  From the results shown in Table 3, it can be seen that according to the production method of the present invention, an olefin can be produced regardless of the chain length of the alcohol. It can also be seen that olefins can be produced under a wide temperature range.

Example 9
A reaction was carried out in the same manner as in Example 3 except that the reaction time such as phosphoric acid was changed as shown in Table 4. The results are shown in Table 4.

It can be seen from Table 4 that an olefin can be obtained at a high reaction rate, regardless of whether the catalyst supports phosphoric acid or its condensate, or the catalyst supports phosphoric acid salt or its condensate.
As described above, the production method of the present invention can produce a long-chain olefin in a high yield in a short reaction time in the dehydration reaction of a long-chain aliphatic primary alcohol.

Claims (6)

  A method for producing an olefin, wherein a dehydration reaction of an alcohol is carried out in the presence of a catalyst in which at least one selected from phosphoric acid, a phosphate, and a condensate thereof is supported on titanium oxide.   The method for producing an olefin according to claim 1, wherein the catalyst is obtained by supporting at least phosphoric acid and / or a condensate thereof on titanium oxide.   The method for producing an olefin according to claim 1 or 2, wherein the alcohol is a primary alcohol having 12 to 24 carbon atoms.   The manufacturing method of the olefin in any one of Claims 1-3 which perform the said dehydration reaction at 200-300 degreeC.   The method for producing an olefin according to claim 1, wherein the dehydration reaction is performed in a liquid phase.   The production of an olefin according to any one of claims 1 to 5, wherein the supported amount of at least one selected from the phosphoric acid, the phosphate, and a condensate thereof is 1 to 50% by mass of the mass of titanium oxide. Method.