JP2005162706A - Method for producing medium-chain aliphatic alcohol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the industrially advantageous production of a 6-10C medium-chain aliphatic alcohol by the hydrogenative reduction of a 6-10C medium-chain aliphatic carboxylic acid methyl ester in the presence of a chromium-free catalyst. <P>SOLUTION: A 6-10C medium-chain aliphatic alcohol is produced by the hydrogenative reduction of a 6-10C medium-chain aliphatic carboxylic acid methyl ester in a suspension bed bubble column reactor in the presence of a copper-zinc oxide catalyst and/or a copper-zinc-aluminum oxide catalyst. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a medium chain aliphatic alcohol having 6 to 10 carbon atoms by hydrogen reduction of a medium chain aliphatic methyl carboxylate having 6 to 10 carbon atoms.

  Conventionally, long-chain aliphatic carboxylic acid esters in the presence of oxide catalysts such as copper-chromium oxide and copper-zinc oxide are 200 to 300 ° C. (practical reaction temperature 280 to 300 ° C.), 200 to 300 atmospheres (hydrogen pressure). As a method for continuously producing a corresponding long-chain aliphatic alcohol by hydrogen reduction under high temperature and high pressure conditions, a fixed bed method is a known method (Non-patent Document 1).

  However, the fixed bed method has the following various problems. For example, 1) It is easily affected by impurities such as sulfur compounds, organochlorine compounds, and high molecular weight compounds in the raw material, and the catalyst is deteriorated or the catalyst life is shortened. 2) A conventional high quality aliphatic alcohol is obtained. In order to achieve this, it is necessary to stop the operation for several months and replace it with a new catalyst. However, it takes about 2 to 4 weeks for this replacement to take about 2 to 4 weeks, which is very disadvantageous in terms of economy. It is done.

  Furthermore, since the copper-chromium oxide catalyst contains harmful chromium, it is a problem from the viewpoint of work safety and environmental safety, and an alternative catalyst for this is strongly demanded.

Japan Oil Chemists' Society Petroleum Chemistry Handbook (4th edition), page 458

  The above method is an effective method for continuously hydrogen reducing a long-chain aliphatic alcohol from a long-chain aliphatic carboxylic acid ester. However, since the above method is premised on producing a long-chain aliphatic alcohol having 12 or more carbon atoms, there is a limit to producing a medium-chain aliphatic alcohol having 6 to 10 carbon atoms. That is, in the practical reaction temperature range employed in the above method, the reaction cannot be continued because the medium-chain aliphatic alcohol having a high vapor pressure evaporates, or the reaction is performed to suppress the evaporation of the medium-chain aliphatic alcohol. When the temperature is lowered, there is a problem that the catalytic activity is lowered.

  Therefore, since it is understood that the conventional fixed bed method has many problems and is economically disadvantageous as a production method of medium chain aliphatic alcohol, a method capable of solving these problems is required. Yes.

  The present invention provides a method for industrially advantageously producing a medium chain aliphatic alcohol by continuously hydrogen reducing a medium chain aliphatic carboxylic acid ester in the presence of a non-chromium-containing catalyst having a low catalytic activity temperature. With the goal.

  As a result of intensive studies to solve such problems, the present inventors have used a suspended bed bubble column type reactor as a specific reactor, and obtained a medium chain aliphatic carboxylate having 6 to 10 carbon atoms. It has been found that medium chain aliphatic alcohols having 6 to 10 carbon atoms can be advantageously produced industrially by hydrogen reduction in the presence of a specific catalyst, and the present invention has been completed.

  That is, this invention provides the manufacturing method of the following C6-C10 medium chain aliphatic alcohol.

  [1] Using a suspended bed bubble column reactor, in the presence of a copper-zinc oxide catalyst and / or a copper-zinc-aluminum oxide catalyst, a medium chain aliphatic methyl carboxylate having 6 to 10 carbon atoms is added. The present invention relates to a method for producing a medium-chain aliphatic alcohol having 6 to 10 carbon atoms, characterized by performing continuous hydrogen reduction.

  [2] Hydrogen reduction is performed in the presence of a copper-zinc oxide catalyst and / or a copper-zinc-aluminum oxide catalyst, a reaction temperature of 230 to 250 ° C., a reaction pressure of 15 to 30 MPa, and a hydrogen gas superficial linear velocity of 2 to 5 cm. The method according to [1], which is performed at a rate of 1 second.

  [3] The production method according to the above [1] or [2], wherein the methyl medium chain aliphatic carboxylate is a natural methyl chain aliphatic carboxylate obtained from coconut oil and / or palm kernel oil.

  According to the present invention, a medium-chain aliphatic alcohol having 6 to 10 carbon atoms having a high vapor pressure can be industrially advantageously produced by hydrogen reduction of a medium-chain aliphatic carboxylate having 6 to 10 carbon atoms. it can.

As suspension bed reactors, suspension bed bubble column reactors and suspension bed stirrer reactors are known. The reactor used in the present invention is the former. The former is free from problems such as a shaft seal of a stirrer, is easy to maintain the reactor, is low in construction cost, and is suitable for mass production. On the other hand, the latter is likely to leak from the shaft seal, and the reactor volume is limited to about 1 m ³ , which is unsuitable for mass production.

  In the latter case, since the reduction catalyst shows a behavior of moving along the inner wall surface of the reaction tank by stirring, a tendency that the contact efficiency tends to be low is observed. On the other hand, in the former case, since the reduction catalyst is in efficient contact with hydrogen, it becomes possible to produce an aliphatic alcohol with a high yield in a short time. The shape of the reactor is not particularly limited, but a cylindrical type is usually used.

  As the medium chain aliphatic methyl carboxylate having 6 to 10 carbon atoms used as a raw material, in addition to natural medium chain aliphatic methyl carboxylate obtained from coconut oil, palm kernel oil, beef tallow, lard, etc. Examples include methyl chain aliphatic carboxylates, and natural methyl chain aliphatic carboxylates are preferable. In particular, methyl chain aliphatic carboxylates obtained from coconut oil and / or palm kernel oil are preferred for reduction reactivity and availability. Recommended for ease of use.

  Specific examples of the medium chain aliphatic methyl carboxylate include methyl hexanoate, methyl heptanoate, methyl octanoate, methyl 2-ethylhexanoate, methyl nonanoate, methyl isononanoate, methyl decanoate and the like. In addition, these medium-chain aliphatic methyl carboxylates may be linear or branched, and may have at least one double bond in the molecule. These medium chain aliphatic carboxylates can be used alone or in admixture of two or more.

  The compound to be subjected to hydrogen reduction in the present invention is not particularly limited to the above-mentioned medium-chain aliphatic carboxylate methyl, but is preferably an alicyclic carboxylic acid lower (such as methyl cyclohexanecarboxylate) having 1 to 4 carbon atoms, particularly , Methyl) alkyl esters, aromatic carboxylic acid lower (C1-C4, especially methyl) alkyl esters such as methyl benzoate and dimethyl phthalate can also be used.

  Although it does not specifically limit as a manufacturing method of the said medium chain aliphatic carboxylate, For example, natural oil and fat and methyl alcohol are 30-90 degreeC in the presence of alkali catalysts, such as sodium hydroxide and potassium hydroxide. The method of distilling under reduced pressure after carrying out transesterification reaction under normal pressure to 0.3 MPa under heating, or the fatty acid obtained by hydrolyzing natural fats and oils under reduced pressure, A known production method such as a method of obtaining a chain aliphatic carboxylic acid and methyl esterifying the medium chain aliphatic carboxylic acid with methyl alcohol in the presence of an acid catalyst or without a catalyst.

  The hydrogen reduction catalyst used in the present invention is a powdery catalyst. Examples of the powdery catalyst include a copper-zinc oxide catalyst and / or a copper-zinc-aluminum oxide catalyst, and molybdenum, tungsten, magnesium, and these catalysts. , Barium, calcium, zirconium, silicon and modified catalysts to which these oxides are added are used. These powdery catalysts can be used directly, but can also be used by being supported on a carrier such as activated carbon, silica, alumina, titania and zeolite. The production method of these supported catalysts is not particularly limited, but can be easily produced by a conventionally known method such as an impregnation method or a coprecipitation method.

  These powdery catalysts may be commercially available and are not particularly limited.

In the copper-zinc oxide catalyst used, the ratio (weight ratio) of copper oxide to zinc oxide is not particularly limited, but is preferably CuO / ZnO = 40-60 / 40-60, particularly preferably 45-55 / It is the range of 45-55. Also, copper - zinc - copper oxide in aluminum oxide catalyst, as a ratio of the zinc oxide and aluminum oxide (weight ratio) is in _the range of _{CuO / ZnO / Al 2 O 3} = 40~50 / 40~50 / 2~10 Is recommended.

  Although it does not specifically limit as an average particle diameter of these powdery catalysts, From a reactive and filterability viewpoint, it is the range of 1 micrometer-150 micrometers, Preferably it is 3 micrometers-50 micrometers.

  The amount of the catalyst used can be appropriately selected depending on the type and amount of the reaction raw material, the catalyst, and the operating conditions, and is not particularly limited, but is preferably 0.5 to, for example, with respect to the medium-chain aliphatic carboxylate. A range of 10% by weight, particularly preferably 1-5% by weight, is recommended. If the amount is less than 0.5% by weight, the reaction rate is low. On the other hand, if the amount exceeds 10% by weight, operational problems such as clogging of piping (particularly, a high pressure valve) tend to occur.

  Although a solvent can be used for the reaction, it is preferably carried out without a solvent in consideration of productivity. Examples of the solvent include alcohols, ether compounds, hydrocarbons and the like that do not affect the reaction.

  By using the catalyst according to the present invention, a high reaction rate can be obtained even at a low temperature as compared with the conventional catalyst. Here, as reaction temperature, 230-250 degreeC is preferable, More preferably, it is 240-250 degreeC. In particular, 245 to 248 ° C is recommended. When the reaction temperature is less than 230 ° C., the reaction rate is low. On the other hand, when the reaction temperature exceeds 250 ° C., the produced aliphatic alcohol having a high vapor pressure evaporates with hydrogen gas and tends to be in a highly concentrated slurry state. Furthermore, if the evaporation of the aliphatic alcohol proceeds, only the catalyst is dried in the reactor, which is not preferable for industrial implementation.

  As reaction pressure, 15-30 Mpa is preferable, More preferably, it is 18-25 Mpa. When the reaction pressure is less than 15 MPa, the reaction rate is low. On the other hand, when the reaction pressure exceeds 30 MPa, the construction cost of the apparatus is increased, for example, a special reaction apparatus is required, leading to an increase in cost.

  As the reaction time, an average residence time of 0.2 to 4 hours is recommended. When the average residence time is long, the evaporation amount of the produced alcohol is large and it tends to be difficult to control the reaction. On the other hand, when the average residence time is short, the reaction rate tends to be low.

  The hydrogen gas superficial linear velocity is preferably 2 to 5 cm / second, more preferably 3 to 4 cm / second. If it is less than 2 cm / sec, the reaction rate is low, while if it exceeds 5 cm / sec, the catalyst tends to be too concentrated.

  Specific examples of the reaction method include the following processes, but the present invention is not limited to this process. FIG. 1 is a combination of a suspended bed bubble column reactor, a high pressure gas-liquid separator and a filter.

  In FIG. 1, a hydrogen introduction pipe 2 and a suspension of catalyst and medium chain aliphatic methyl carboxylate (hereinafter referred to as “raw material suspension”) introduction pipe 3 are arranged at the bottom of a cylindrical reactor 1. It is installed. The structure is such that hydrogen bubbles are ejected from the hydrogen introduction tube into the reaction solution through a filter. In this apparatus, hydrogen gas, product aliphatic alcohol and catalyst (hereinafter referred to as “product suspension”) are discharged from a discharge pipe 4 at the top of the reaction tower to a gas-liquid separator 5 to generate hydrogen gas and a product. Separated into a product suspension. Further, the product suspension is filtered from the catalyst and the aliphatic alcohol by a filter 6. As a filter, the usual apparatus normally used in the said field | area, such as a Funder type filter, can be used. Here, the catalyst and the recovered hydrogen gas can be discarded or recycled, and are preferably reused from the economical aspect.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Production Example 1 (Production of medium chain aliphatic methyl carboxylate)
Transesterification of palm kernel oil with methyl alcohol was carried out according to a conventional method to obtain a medium-chain aliphatic methyl carboxylate. The obtained medium-chain aliphatic carboxylate methyl was rectified, and a medium-chain aliphatic carboxylate having 6 to 10 carbon atoms (gas chromatography composition: methyl caproate 2% by weight, methyl caprylate 30% by weight, capric acid 68% by weight of methyl) was obtained.

Example 1
Medium chain aliphatic carboxylic acid methyl and copper of the 6 to 10 carbon atoms - zinc - suspension of aluminum catalyst _{(CuO / ZnO / Al 2 O} 3 = 43.0 / 44.0 / 5.5 ( weight ratio)) A cylindrical high-pressure bubble column (inner diameter: 30 cm x length: 3.2 m) that overflows the solution (catalyst concentration of 1% by weight) at 200 L, and hydrogen gas from the bottom of the bubble column reactor at a superficial linear velocity of 3 cm / sec. While maintaining the reaction temperature at 246 ° C., it was supplied at 100 L / h (average residence time 2 hours) and continuously operated for 100 hours to obtain an aliphatic alcohol as a hydrogen reduction product. It was confirmed that a steady state was reached 24 hours after the start of the reaction. As a result of gas chromatographic analysis of the reaction product solution at a constant time, the reaction rate of methyl chain aliphatic carboxylate was 97 to 98%, and the catalyst concentration was 1% by weight.

Comparative Example 1
When hydrogen reduction was performed in the same manner as in Example 1 except that a copper-chromium oxide catalyst was used as the catalyst, the reaction rate of the medium-chain aliphatic carboxylate was 52%.

Comparative Example 2
In Comparative Example 1, when the reaction temperature was raised from 246 ° C. to 290 ° C., the catalyst concentration in the discharged liquid decreased to 0.5% by weight or less. Continuation of the reaction beyond this was stopped due to the risk of blockage of the piping due to the catalyst supplied into the high-pressure bubble column.

  The aliphatic alcohol according to the present invention is a material useful as a raw material for various industrial base materials such as surfactants.

FIG. 1 is a drawing showing a preferred embodiment of a suspended bed bubble column reactor according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Suspension bubble column type reactor 2 ... Hydrogen introduction pipe 3 ... Raw material suspension introduction pipe 4 ... Discharge pipe 5 ... High pressure gas-liquid separator 6 ... Filter

Patent applicant New Nippon Rika Co., Ltd.

Claims (3)

  Using a suspended bed bubble column reactor, hydrogen reduction of a medium-chain aliphatic carboxylate having 6 to 10 carbon atoms is carried out in the presence of a copper-zinc oxide catalyst and / or a copper-zinc-aluminum oxide catalyst. A process for producing a medium chain aliphatic alcohol having 6 to 10 carbon atoms.   The production method according to claim 1, wherein the hydrogen reduction is performed under reaction conditions of a reaction temperature of 230 to 250 ° C, a reaction pressure of 15 to 30 MPa, and a hydrogen gas superficial linear velocity of 2 to 5 cm / sec. The production method according to claim 1 or 2, wherein the medium chain aliphatic methyl carboxylate is a natural medium chain aliphatic methyl carboxylate obtained from coconut oil and / or palm kernel oil.

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