JP2002167356A - Method for producing fatty ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fatty ester which makes it possible to produce the fatty ester under a moderate condition without any problem of remaining of catalyst in glycerin with phase separation property and purify easily the ester without any need of a separating and removing apparatus. SOLUTION: A method for producing a fatty ester of the present invention is characterized by using a volatile catalyst as the catalyst when the fatty ester is produced by transesterification in the presence of the catalyst among oils and fats and alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a fatty acid ester.

[0002]

2. Description of the Related Art Catalysts for transesterification of triglycerides contained in fats and oils include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide and alkaline earth metals such as calcium hydroxide and magnesium hydroxide. Hydroxides are commonly used. Since such a catalyst remains in the reaction system after the transesterification reaction, a purification step such as a water washing step or an ion exchange step for removing the catalyst is required, and equipment for separating and removing the catalyst is usually required. Further, there is a problem that the catalyst remains in the glycerin phase to be phase-separated and glycerin cannot be reused immediately.

There is a method using a solid acid catalyst as a transesterification catalyst. However, there are problems such as a low transesterification reaction speed, a long reaction time, and a large transesterification facility.

In recent years, as a method without using a catalyst for the transesterification reaction, there is a method in which a reaction is carried out in a supercritical alcohol as disclosed in JP-A-2000-143586. In order to achieve a supercritical state, high-temperature and high-pressure conditions are required, and there is a problem that manufacturing equipment becomes expensive.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a fatty acid ester which can be easily purified without requiring a catalyst separation / removal facility, and which is free from the problem of remaining catalyst in glycerin undergoing phase separation under mild conditions. It is an object of the present invention to provide a method for producing a fatty acid ester efficiently at a temperature.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, when a volatile catalyst is used as a catalyst for the transesterification reaction, a simple method such as distillation is used after the transesterification reaction. It has been found that the catalyst can be separated by a simple operation, and that no catalyst remains in glycerin to be phase-separated, thereby completing the present invention.

That is, the present invention is characterized in that (1) a volatile catalyst is used as the catalyst in producing a fatty acid ester by performing a transesterification reaction between an oil and a fat and an alcohol in the presence of a catalyst. (2) The method for producing a fatty acid ester according to the above (1), wherein the volatile catalyst is an amine, and (3) the volatile catalyst and unreacted alcohol are distilled off after the transesterification reaction is completed. The method for producing a fatty acid ester according to the above (1) or (2), which is separated and removed outside the reaction system,
(4) The method for producing a fatty acid ester according to any one of the above (1) to (3), wherein the transesterification reaction is performed under a pressure higher than the atmospheric pressure, (5) the above (1), wherein the alcohol is methanol and / or ethanol. (6) The method for producing a fatty acid ester according to any one of (1) to (5), wherein the fat or oil is a waste cooking oil, and (7) a volatile catalyst. The present invention relates to the method for producing a fatty acid ester according to any one of the above (1) to (6), wherein water is used as a co-catalyst.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION One major feature of the method for producing a fatty acid ester of the present invention is to use a volatile catalyst as a catalyst. By using such a catalyst, a transesterification reaction can be efficiently carried out between an ester contained in fats and oils and an alcohol under mild conditions.
In addition, since the catalyst can be easily separated and removed from the reaction system by a simple operation such as distillation after the completion of the reaction, the fatty acid ester can be easily purified without requiring equipment for separating and removing the catalyst, and furthermore, the phase is separated. The resulting glycerin can be immediately reused without the problem of residual catalyst in glycerin.

The fats and oils used in the present invention are not particularly limited, and general fats and oils such as soybean oil, coconut oil, palm oil, palm kernel oil, linseed oil, cottonseed oil, rapeseed oil, drill oil, castor oil, beef tallow, etc. Examples thereof include waste cooking oil discarded from food factories, general households, and the like, and fats or oils obtained by mixing these fats or oils alone or processed fats and oils mainly containing these fats and oils can be used as raw materials. In the present invention, it is preferable to use waste cooking oil from the viewpoint of resource reuse.

The alcohol used in the present invention is not particularly restricted but includes methanol, ethanol, n-propanol, i
-Propanol, n-butanol, i-butanol, 2
General alcohols such as -butanol and t-butyl alcohol can be exemplified, and these alcohols can be used alone or in combination of two or more. In the present invention, it is preferable to use methanol and / or ethanol from the viewpoint of easy availability and availability of the obtained fatty acid ester.

The volatile catalyst used in the present invention is a liquid at the temperature and pressure at which the transesterification reaction is carried out, and is the boiling point of fats and oils as reaction raw materials, fatty acid esters and glycerin as reaction products. There is no particular limitation as long as it is a volatile catalyst having a lower boiling point, but from the viewpoint of easily distilling and removing such a catalyst, a volatile catalyst having a boiling point whose difference from the boiling point of the reaction raw material or the like is 50 ° C. or more is used. Neutral catalysts are preferred. Among them, strong basicity,
From the viewpoint of high solubility in fats and oils and / or alcohols, amines are preferred.

Examples of such amines include methylamine,
Dimethylamine, trimethylamine, allylamine, diallylamine, triallylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, 2-ethylhexylamine,
Examples thereof include propylamine, n-butylamine, t-butylamine, sec-butylamine, and monoethanolamine, and from the viewpoints of economy, low boiling point, and low operating pressure, ethylamine, diethylamine, and triethylamine are preferable.

The above-mentioned catalysts can be used alone or in combination of two or more.

As a method for producing a fatty acid ester according to the present invention, raw materials such as fats and oils, alcohols and volatile catalysts are continuously supplied to a reaction reactor for transesterification, and a fatty acid ester as a reaction product, glycerin, A continuous method of discharging residual oils and fats, alcohol and volatile catalyst, which is a material, and reacting after the required amount of raw materials such as oils and fats, alcohol and volatile catalyst per batch are charged into the reaction reactor, and the reaction is performed. Fatty acid ester, glycerin, unreacted residual oils and fats, alcohol, it is possible to adopt any of batch type to extract the reaction mixture containing a volatile catalyst, from the viewpoint of easy operation, In the following description, a description will be given of a batch method. In addition,
In the following, “parts” means “parts by weight”.

The amount of alcohol charged to 100 parts of the fat or oil used as a raw material varies depending on the average molecular weight of the fat or oil, but can be generally expressed as a multiple of the chemical equivalent calculated by the following formula (1). The average molecular weight of fats and oils is M
o, where the average molecular weight of alcohol is Ma, the equivalent charged amount Wa (part) of alcohol is calculated by the following formula: Wa = 100 / Mo × 3 × Ma (1) The amount of the alcohol is preferably 1.05 to 20 times the equivalent charged amount Wa calculated by the formula (1).
2 times, more preferably 1.1 times to 10 times. If the alcohol charge ratio is within this range,
The transesterification reaction proceeds sufficiently, which is preferable from an economic viewpoint. The average molecular weight is calculated based on the composition of fats and oils and alcohol as raw materials.

For example, when the average molecular weight of the fats and oils is 880 and the alcohol is methanol (average molecular weight 32), methanol is preferably added to 100 parts of the fats and oils.
1.45 parts to 218.2 parts, more preferably 12 parts to
Prepare 109.1 copies.

The amount of the volatile catalyst to be charged into the reaction reactor is preferably from 0.5 to 100 parts, more preferably from 1 to 30 parts, per 100 parts of oils and fats. When the charged amount of the volatile catalyst is within the above range, the transesterification reaction proceeds sufficiently, which is preferable from an economic viewpoint.

Further, in the method for producing a fatty acid ester of the present invention, from the viewpoint of promoting the ionic dissociation of the volatile catalyst, sufficiently exerting the action of the catalyst, and favorably proceeding the reaction, the volatile catalyst may be further used. It is preferred to use water as co-catalyst. Such water is not particularly limited as long as the desired effect of the present invention is not inhibited, and examples thereof include tap water, distilled water, ion-exchanged water, and ultrapure water. In addition, when water is already contained in fats and oils or alcohol, the same effect as when water as a co-catalyst is added can be obtained without actively adding water.

The amount of the cocatalyst to be charged into the reaction reactor is preferably 0.05 to 20 parts, more preferably 0.5 to 10 parts based on 100 parts of oils and fats. It is preferable that the charged amount of water as the co-catalyst be within the above range, since the desired effect of the co-catalyst is well exhibited.

As a reaction reactor, that is, a vessel for providing a reaction field, a flask, a steel vessel, a steel pipe, a static mixer, a stirring tank, and the like can be used. The material of the reaction reactor is not particularly limited, and glass, iron and steel, stainless steel, Ni alloy, Ti alloy, glass lining steel, polymer lining steel, ceramic lining steel and the like can be used.

After a predetermined amount of fats and oils, an alcohol, a volatile catalyst and, if desired, water are charged into the reaction reactor, the contents in the reaction reactor are heated to a predetermined reaction temperature to start the reaction. The order of charging the components is not particularly limited. The heating method may be performed by charging each raw material while heating it with a heat exchanger at the time of charging, or may be performed by externally heating the reaction reactor after charging. The reaction temperature is preferably from 50C to 200C, more preferably from 60C to 150C. The reaction pressure corresponds to the vapor pressure at the reaction temperature indicated by the volatile substance charged in the reaction reactor.
The reaction is preferably performed under a pressure of 1 MPa or more.
It is more preferable to carry out the reaction under a pressure of 2 MPa or more.
Further, the pressure is preferably 1 MPa or less, and 0.9 MPa
It is more preferably not more than a. When the reaction temperature and the reaction pressure are within the above ranges, the transesterification reaction rate is sufficient, and the reaction can be favorably and rapidly performed, which is preferable. The reaction time varies depending on the reaction temperature and the type of the raw material used, and cannot be unconditionally determined.
It is selected in the range of 4 hours. During the reaction, it is preferable to perform stirring from the viewpoint of accelerating the reaction.

In a particularly preferred embodiment of the method for producing a fatty acid ester of the present invention, oils and fats and alcohols as raw materials, amines as a volatile catalyst, and water as a cocatalyst are charged into the reaction reactor at the above-mentioned preferable charging amounts. The reaction temperature is 60 ° C to 150 ° C and the reaction pressure is 0.1.
In this embodiment, the transesterification is performed at a pressure of 2 MPa to 0.9 MPa. According to such an embodiment, during the reaction, the catalytic activity of the volatile catalyst can be kept high, and the reaction can proceed efficiently and more quickly.

After completion of the transesterification reaction, the obtained reaction mixture is cooled to a desired temperature and allowed to stand at the temperature or at room temperature, or as it is at room temperature.
The fatty acid ester can be obtained by phase-separating the fatty acid ester and glycerin. However, since such a fatty acid ester contains an unreacted substance, a catalyst and the like, it is preferable to further purify the fatty acid ester. The method for purifying the fatty acid ester is not particularly limited, and any known purification method can be used. However, from the viewpoint of easy operation, distillation is preferred. By such distillation, the volatile catalyst can be separated and removed substantially completely outside the reaction system, and unreacted alcohol can be separated and removed at the same time. The obtained fatty acid ester can be immediately commercialized without requiring a further purification step, and glycerin can be immediately reused because it does not contain a catalyst. The volatile catalyst and unreacted alcohol recovered by distillation can be reused as raw materials for the next batch in the case of a batch system, and as recycled materials in the case of a continuous system.

The distillation method for separating and removing the volatile catalyst and unreacted alcohol is not particularly limited, and any known method may be used. After completion of the transesterification reaction, the obtained reaction mixture is cooled to a desired temperature and subjected to distillation. The distillation temperature is not particularly limited as long as the volatile catalyst and unreacted alcohol can continue to evaporate. Further, the pressure of distillation may be any of pressurization, normal pressure and reduced pressure as long as a desired effect is obtained.

The fatty acid ester obtained as described above has a sufficiently high purity and can be directly used as a fuel alternative to light oil.

[0026]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 100 g of a commercially available salad oil (trade name: Nisshin Salad Oil (estimated average molecular weight 887), manufactured by Nisshin Oil) 100 g of methanol
(Equivalent charging amount is 10.82 g, methanol charging ratio is 4.62 times), diethylamine 20 g and water 10 g are added to 5
Charge into a 00ml pressure resistant glass flask, 700rpm
While stirring at a stirring speed of, the internal temperature is reduced to 1 with an electric heater.
The temperature was raised to 30 ° C. The pressure at this time is a gauge pressure of 0.1.
It showed 65 MPa. After the temperature was raised to 130 ° C., the reaction was performed for 3 hours while stirring was continued. After the reaction, 7
After cooling to 0 ° C. and distilling off diethylamine and unreacted methanol at normal pressure, distillation was carried out at an absolute pressure of 13.3 kPa until diethylamine and unreacted methanol stopped flowing out. After the distillation, 92 g of a fatty acid ester phase (upper layer) and 15 g of a glycerin phase (lower layer) were obtained as reaction liquids. Nitrogen analysis (gas chromatography analysis; instrument:
The amount of residual amine in the fatty acid ester phase by GC-14B manufactured by Shimadzu Corporation was 200 ppm or less. Also,
The amount of residual amine in the glycerin phase was measured in the same manner and 200 p
pm or less.

Comparative Example 1 100 g of the commercially available salad oil and 15 g of methanol (equivalent charge amount was 10.82 g, methanol charge ratio was 1.3)
9 times), 1.5 g of caustic potash was charged into a 500 ml pressure-resistant glass flask, and the internal temperature was raised to 70 ° C. with an electric heater while stirring at a stirring speed of 700 rpm. The pressure at this time was normal pressure. After heating to 70 ° C,
The reaction was performed for 3 hours while stirring was continued. After completion of the reaction, distillation was performed at 13.3 kPa absolute pressure until no unreacted methanol flowed out. After distillation, as a reaction solution,
93 g of a fatty acid ester phase (upper layer) and 16 g of a glycerin phase (lower layer) were obtained. Ash content measurement (JIS K227
The amount of residual potassium in the fatty acid ester phase according to 2) is 0.
It was 8% by weight. Further, the amount of residual caustic potash in the glycerin phase was measured in the same manner and found to be 4.6% by weight.

According to the method for producing a fatty acid ester of the present invention, highly purified fatty acid ester and glycerol substantially free of a catalyst can be obtained by performing only a simple distillation operation.

[0030]

According to the present invention, a fatty acid ester can be efficiently produced under mild conditions, and a purified fatty acid ester can be easily obtained without the need for a catalyst separation and removal facility. . Glycerin obtained at the same time does not contain a catalyst, so that it can be reused immediately.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsushi Sakai 17-family, Chudo-ji Minamicho, Shimogyo-ku, Kyoto-shi, Kyoto (72) Inside the Kansai New Technology Research Institute Co., Ltd. Address: Kansai New Technology Research Institute Co., Ltd. 17 Teranicho F-term in Kansai New Technology Research Institute Co., Ltd. 4H006 AA02 AC48 AD11 BA28 BA29 BA51 BC11 KA03 4H039 CA66 CD10 CD40 CE10

Claims (7)

[Claims] 1. A method for producing a fatty acid ester, wherein a volatile catalyst is used as the catalyst when producing a fatty acid ester by performing a transesterification reaction between an oil or fat and an alcohol in the presence of a catalyst. . 2. The method for producing a fatty acid ester according to claim 1, wherein the volatile catalyst is an amine. 3. The method for producing a fatty acid ester according to claim 1, wherein after the transesterification reaction is completed, the volatile catalyst and unreacted alcohol are separated and removed from the reaction system by distillation. 4. The method for producing a fatty acid ester according to claim 1, wherein the transesterification reaction is carried out at a pressure higher than the atmospheric pressure. 5. The method for producing a fatty acid ester according to claim 1, wherein the alcohol is methanol and / or ethanol. 6. The method for producing a fatty acid ester according to claim 1, wherein the fat or oil is waste cooking oil. 7. The method for producing a fatty acid ester according to claim 1, wherein water is used as a cocatalyst of the volatile catalyst.