WO2010016285A1

WO2010016285A1 - Method of producing fatty acid ester and glycerol, biodiesel containing fatty acid ester, and solid catalyst to be used therefor

Info

Publication number: WO2010016285A1
Application number: PCT/JP2009/052336
Authority: WO
Inventors: 新陳; 哲平能村
Original assignee: ズードケミー触媒株式会社
Priority date: 2008-08-04
Filing date: 2009-02-12
Publication date: 2010-02-11
Also published as: JP2010037422A

Abstract

A method of producing a fatty acid ester and glycerol whereby, in producing a fatty acid ester and glycerol by reacting a fat with an alcohol, a catalyst separation step and a product neutralization/washing step, which are shortcomings of the homogeneous phase alkali catalyst method, can be omitted and the production can be conducted in a system at low temperature and atmospheric pressure that is relatively advantageous from the standpoint of production; a biodiesel containing the fatty acid ester produced by the preceding production method; and a solid catalyst having a high activity and being free from elution of metals which can be used in the preceding production method. In a method of producing a fatty acid ester and glycerol from a fat and an alcohol, at least one solid catalyst comprising activated zinc oxide and an alkali carried on the activated zinc oxide is used and the reaction is conducted under mild conditions at atmospheric pressure and 50 to 70^oC.

Description

Process for producing fatty acid ester and glycerol, biodiesel containing fatty acid ester and solid catalyst used

The present invention relates to a method for producing a fatty acid ester and glycerin by reacting oil and fat with alcohol, biodiesel containing the fatty acid ester, and a solid catalyst to be used.

Oils and fats are mainly composed of esters of fatty acids called glycerides and glycerin, and fatty acid esters obtained by transesterification using oils and fats and alcohol are close to the properties of diesel and are called biodiesel. This fuel has the advantage that it can be used as it is without modification to any diesel engine. Moreover, since waste edible oil that contributes to environmental pollution can also be used as a raw material, it is a biomass raw material that can double the environmental burden. In the United States and Europe, we have already started using 1 to 20% biodiesel fuel mixed with petroleum-based diesel fuel, and that alone reduces the load on the engine due to its high lubricity and is environmentally friendly. It has been reported that the burden on health and health has also been reduced.

In recent years, the movement to actively use biodiesel fuel, which is superior to petroleum diesel fuel in all respects, has been gradually increasing in recent years, but at a cost two to three times that of petroleum diesel fuel. There is a big problem. This is because the current biodiesel fuel production process uses a phase-homogeneous alkali catalyst such as potassium hydroxide, which adds to the cost of separating and removing these catalysts during commercialization. There is an urgent need to search for highly active heterogeneous solid catalysts that do not require a separation process.

A method using a complex oxide having a perovskite structure such as CaTiO ₃ or CaMnO ₃ as a heterogeneous solid catalyst for the direct production of biodiesel fuel (see Patent Document 1), A method using an alkaline earth metal oxide, hydroxide or carbonate in a subcritical state (see Patent Document 2), a method using quick lime or bituminous lime (see Patent Document 3), calcium hydroxide or calcium oxide There is known a method using the method (see Patent Document 4). However, these methods have problems such as high temperature required, difficulty in regeneration of the catalyst, expensive catalyst, and insufficient reaction rate.

Further, regarding a method for producing an aliphatic ester, (a) a step of alcoholysis of fats and oils with a heterogeneous catalyst, (b) a step of evaporating excess alcohol from the reaction solution after the alcoholysis, (c) fatty acid alkyl ester and unreacted Separating the mixed solution of glycerin and glycerin to obtain a mixed solution of fatty acid alkyl ester and unreacted edible oil, (d) again using the alcohol recovered in (b) in the presence of a catalyst, , A step of alcoholysis, (e) a method including five steps of evaporating excess alcohol from the reaction solution after alcoholysis, separating fatty acid ester and glycerin to obtain fatty acid ester, preferably including a spinel structure _{_{_{ZnAl 2 O 4, xZnO, yAl}}} 2 O 3 (x and y are 0 to 2) a method using a catalyst is disclosed (for example , See Patent Document 5, 6). However, in this production method, since the activity of the catalyst is low, a high reaction temperature is required.

JP 2002-294277 A JP 2002-308825 A JP 2004-35873 A JP 2001-271090 A US Pat. No. 5,908,946 US Pat. No. 6,147,196

In the production of fatty acid ester and glycerin by reacting oil and fat with alcohol, the present invention can omit the steps of catalyst separation, product neutralization and water washing, which are disadvantages of a soaking alkaline catalyst. It is an object of the present invention to provide a method for producing fatty acid ester and glycerin that can be produced in a system, biodiesel containing the fatty acid ester produced by the production method, and a highly active solid-metal catalyst that can be used in the production method. .

As a result of continual research to solve the above-mentioned problems, the present inventors have found that a solid catalyst containing activated zinc oxide reacts under an appropriate temperature condition, and thus a bio-comprising fatty acid ester produced by a reaction between alcohol and fat. It was found that the synthesis of diesel was highly active and there was no metal elution, and with these catalysts, the synthesis of biodiesel could be realized under mild conditions.

That is, the present invention relates to a method for producing a fatty acid ester and glycerin from fats and oils and alcohol, using at least one solid catalyst consisting of activated zinc oxide and an alkali supported on the activated zinc oxide at atmospheric pressure, It is a manufacturing method of fatty acid ester and glycerol characterized by making it react on 70 degreeC mild conditions.

Moreover, alcohol is shown by following General formula (1),
R-OH (1)
(R represents an alkyl group having 1 to 10 carbon atoms.) More preferably, R in the general formula (1) is an alkyl group having 1 to 4 carbon atoms.

Furthermore, the fats and oils are composed of one or a mixture of two or more selected from soybean oil, rapeseed oil, corn oil, sunflower oil, sesame oil, olive oil, or waste oils thereof. is there.

Further, the method is characterized by reacting alcohol and fat with a molar ratio of 3: 1 to 30: 1 for 1 to 10 hours.

As a solid catalyst to be used, zinc oxide is an active zinc white containing 80% by weight or more of zinc oxide.

In addition, the alkali supported on zinc oxide used for the solid catalyst is one of Group 1 or Group 2 metals, and more preferably, the Group 1 and 2 metals are Li, Na, K, The method is characterized by being at least one selected from Ca and Ba.

Furthermore, the amount of alkali supported on zinc oxide used for the solid catalyst is 1 to 20% by weight.

Also, the alkali used for the solid catalyst is produced from a soluble alkali salt, and more preferably, the soluble alkali salt is a fluoride or nitrate compound of Group 1 and Group 2 metals.

Furthermore, the alkali used for the solid catalyst is a method characterized in that an alkali is supported on zinc oxide by an impregnation method.

The solid catalyst is activated in advance for use, and more specifically, activated by calcination in air at 300 to 700 ° C. for 2 to 10 hours, and more specifically, It is a method characterized in that it is used for the reaction immediately after it is lowered to room temperature after firing.

Furthermore, biodiesel containing the fatty acid ester produced by the above method.

Also, it is a solid catalyst used in the above method.

According to the present invention, there is provided a method for efficiently producing a fatty acid ester and glycerin from fats and oils and alcohol under conditions of normal pressure at a relatively low temperature, and an insoluble solid catalyst is used in the method. The catalyst removal step by washing with water, which is necessary in the production method using a catalyst, is unnecessary, and furthermore, there is almost no elution of the active metal component of the insoluble solid catalyst in the solution after the reaction. The biodiesel containing a fatty acid ester can be provided, and thus has great industrial value, and is useful from the viewpoint of resource reuse and pollution prevention.

It is the schematic of the experimental apparatus of this invention.

The present invention is described in detail below.

The main reaction of the production method of the present invention is represented by the following reaction formula (2).

The oil and fat used in the present invention is not particularly limited, but a vegetable oil mainly containing the triglyceride 1 of fatty acid represented by the reaction formula (2) is preferable. Examples thereof include one kind of soybean oil, rapeseed oil, corn oil, sunflower oil, sesame oil, olive oil, palm oil and the like, or a mixture of two or more thereof. These fats and oils are not limited to clean ones and may be waste oils.

Further, the alcohol used in the present invention (2 in the reaction formula (2)) is not particularly limited, but the general formula R—OH (1)
The alcohol shown by these is preferable.

Examples of the alcohol in which R is an alkyl group include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, cyclohexanol, heptanol and the like. Among these, as the alcohol, R is preferably an alkyl group having 1 to 4 carbon atoms.

Specifically, methanol in which R is a methyl group, ethanol in which R is an ethyl group, propanol in which R is a propyl group, isopropanol in which R is an isopropyl group, n-butanol in which R is an n-butyl group, R Is preferably isobutanol having an isobutyl group, t-butanol having R being a t-butyl group, more preferably methanol or ethanol, still more preferably methanol. Although it does not specifically limit as purity of alcohol, Preferably it is 95% or more, More preferably, it is 98% or more. One kind of alcohol may be used, or two or more kinds may be mixed and used.

It is preferable that the supply amount of alcohol in the reaction of fats and oils with alcohol is 1 to 10 times the theoretical supply amount. If it is less than 1 time, the fats and alcohols may not sufficiently react, and the conversion rate may not be sufficiently improved. If it exceeds 10 times, the amount of alcohol recovered / recycled becomes large, and there is a possibility that the load of utilities in manufacturing cannot be reduced sufficiently. The lower limit is more preferably 2 to 5 times.

In addition, the theoretical supply amount of alcohol referred to in the present invention means the number of moles of alcohol corresponding to fats and oils. Therefore, in terms of molar ratio, alcohol and fat are reacted at a molar ratio of 3: 1 to 30: 1, more preferably 6: 1 to 15: 1.

The temperature condition for reacting the oil and fat of the present invention with alcohol is preferably in the temperature range of 50 ° C to 70 ° C. The time for reacting the oil and fat of the present invention with alcohol is 1 to 10 hours, more preferably 3 to 6 hours, still more preferably 10 to 360 minutes, and most preferably 20 to 120 minutes. The reaction pressure may be normal pressure. Each condition of reaction temperature, reaction time, and catalyst addition amount can be freely selected from the above range as required.However, when the reaction temperature is low, the reaction time and catalyst addition amount are compared to when the reaction temperature is high. Tend to increase.

This reaction can be carried out in various reaction modes. For example, it may be performed by a batch method or a distribution method. Moreover, in this invention, fats and oils and alcohol may be mixed uniformly during reaction. A batch system is preferred. The stirring condition affects the reaction speed. If the stirring speed is high, the reaction can proceed more efficiently.

The reaction mixture after completion of the reaction contains fatty acid ester, glycerin and excess unreacted alcohol, and may further contain other impurities depending on unreacted raw materials and reaction raw materials. Reaction) After the methanol component is vaporized and separated and recovered, the catalyst is separated and recovered by filtration. The filtrate is allowed to stand to separate into light and heavy liquids. In the light liquid, the amount of the fatty acid ester is at least 90% by weight, preferably 98% or more.

The solid catalyst used in the present invention is a compound that activates commercially available zinc oxide containing at least 80% of zinc oxide or a composite compound of an alkaline metal oxide containing the same. The form of the solid catalyst may be, for example, a powder or may be formed into a granule.

Some composite compounds of alkaline metal oxides containing zinc oxide carry an alkali metal on zinc oxide by an impregnation method. Moreover, as a kind of alkali, it is at least 1 sort (s) selected from a 1st and 2nd group metal, Preferably, it is at least 1 sort (s) selected from Li, Na, K, Ca, and Ba. The amount of alkali supported is 1 to 20% by weight, preferably 5 to 10% by weight. In preparing the catalyst, the alkali precursor is a soluble salt of the metal, preferably a metal fluoride or nitrate.

All solid catalysts described in the present invention need to be activated before use. The activation method is a method of baking in air at 300 to 700 ° C., preferably 400 to 600 ° C. for 2 to 10 hours, preferably 3 to 5 hours. The calcined catalyst is preferably used for the reaction as soon as possible when the temperature is lowered to room temperature.

Also, the amount of catalyst used is preferably 1 to 8 parts by weight per 100 parts by weight of fats and oils. Furthermore, 2 to 5 parts by weight is more preferable.

The solid catalyst used in the present invention can be separated from the reaction solution only by filtration as compared with a caustic soda catalyst, etc., and is relatively easy because there is no metal elution, and the post-treatment of the reaction solution is simple. . The light liquid contains a fatty acid methyl ester as a main component and can be used as a raw material for diesel fuel, that is, biodiesel and natural higher alcohol. Moreover, the heavy liquid of a glycerol main component can be utilized as a raw material of industrial glycerol. In addition to distillation such as vacuum distillation, typical examples of unreacted alcohol separation include mixer-settler extraction, liquid-liquid extraction, extraction using a pulse column, jet extraction, and Bodbierniac rotary extraction. However, it is not limited to this.

The method for producing the fatty acid alkyl ester and / or glycerin of the present invention is a method of reacting fats and alcohols with an insoluble solid catalyst. Therefore, the catalyst removal step by water washing which is necessary in the conventional production method using a homogeneous catalyst is not necessary, and this is an advantageous production method in this respect. Since there is almost no elution of the active metal component of the insoluble solid catalyst in the solution after the reaction, a high-purity fatty acid ester or glycerin can be advantageously produced in terms of energy.

In the present invention, the presence or absence of elution of the active metal component of the catalyst in the reaction solution obtained by reacting oils and fats with alcohol using an insoluble solid catalyst is determined by the fluorescent X-ray analysis method ( XRF).

In the method of the present invention, the alcohol recovered by the step of distilling off the light boiling component (alcohol) from the reaction solution after the reaction can be reused. Further, the solid catalyst obtained by filtering the light boiling component removing liquid can be recycled as it is or after being reactivated. The upper layer where the filtrate is stationary contains mainly fatty acid ester that becomes biodiesel, and in the fatty acid ester component, the elution of the metal component of the catalyst was used as a reactant as a blank sample as a result of XRF measurement. Little compared to vegetable oil. The lower layer contains glycerin that is nearly colorless.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Reaction conditions)
Reactor: Batch type, 500 ml three-neck flask Reactant: Soybean oil 100 g, Methanol 44 g
Reaction temperature: The reaction is maintained by heating to a reaction temperature of 64 ° C. and methanol reflux in a water bath.
Stirring speed: 250 rpm or more Pressure: Normal pressure catalyst: 5 g

(Analysis conditions)
Instrument: High pressure liquid chromatography (HPLC) LC-system, RID-10A (differential refraction detector), Shimadzu Corporation Column: Silica gel ZORBAX Rx-SIL (4.6 × 250 mm, 5 μm), working temperature 40 ° C.
Moving bed: 0.8% isopropanol / hexane

The operation procedure will be described below in the embodiment.

Example 1
After putting 5 g of activated zinc oxide powder as a solid catalyst in a 500 ml three-necked flask in advance, 44 g of methanol was added as alcohol (see FIG. 1). After lightly mixing, 100 g of soybean oil was added. Thereafter, a stirrer and a Dimroth were set, and the reaction was carried out for 6 hours while methanol was refluxed in a water bath, and then distilled to recover excess methanol for recycling. After the subsequent reaction product was filtered, the catalyst was recovered. The filtrate was allowed to stand overnight and separated into light and heavy liquids. The light layer (upper layer) is mainly composed of fatty acid methyl ester which is biodiesel. A certain amount of the light layer solution was sampled, diluted with hexane, and analyzed by HPLC. Although only two peaks appeared in HPLC, as a result of identification, one peak was a component certified as a fatty acid methyl ester, and the other peak was certified as soybean oil. The amount of fatty acid methyl ester contained in the light layer and the amount of residual soybean oil was calculated based on the HPLC data for each peak, and the yield of fatty acid methyl ester was calculated as shown in Table 1.

Yield of fatty acid methyl ester: Amount of methyl ester produced at the end of the reaction / amount of vegetable oil charged × 100%.

At the same time, the results of measuring XRF in the collected liquid are shown in Table 2.

(Example 2)
The experiment was performed in the same manner as in Example 1 except that the reaction time was shortened to 1 hour.

(Example 3)
A similar experiment was performed using activated 10% -Li ₂ O / ZnO instead of the activated zinc oxide used in Example 1.

Example 4
A similar experiment was conducted using activated 10% -BaO / ZnO instead of the activated zinc oxide used in Example 1.

(Example 5)
A similar experiment was performed using activated 10% -K ₂ O / ZnO instead of the activated zinc oxide used in Example 1.

(Comparative Example 1)
A similar experiment was conducted using non-activated zinc oxide instead of the activated zinc oxide used in Example 1.

(Comparative Example 2)
Experiments were performed in the same manner using CaO instead of the activated zinc oxide used in Example 1.

(Comparative Example 3)
A similar experiment was conducted using MgO instead of the activated zinc oxide used in Example 1.

(Comparative Example 4)
A similar experiment was performed using KOH instead of the activated zinc oxide used in Example 1.

From the results shown in Table 1, when the solid catalyst containing the activated zinc oxide of the example according to the method of the present invention is used, a very high yield of biodiesel is obtained as compared with that using the catalyst of the comparative example. Fatty acid methyl ester was obtained. Furthermore, according to the results of Table 2, in the examples according to the method of the present invention, the elution of the metal components of the used catalyst into the reaction solution was hardly compared to the vegetable oil used as a reactant as a blank sample.

ADVANTAGE OF THE INVENTION According to this invention, the catalyst which can manufacture the biodiesel containing a fatty acid ester efficiently from fats and oils and alcohol on the conditions of a comparatively low temperature and a normal pressure, and the method of manufacturing biodiesel by it are provided. And its industrial value is great. It is also useful from the viewpoint of resource reuse and pollution prevention.

Claims

In a method for producing a fatty acid ester and glycerin from fats and oils and alcohol, at least one solid catalyst comprising an activated zinc oxide and an alkali supported on the activated zinc oxide is used at normal pressure and mild conditions of 50 to 70 ° C. A method for producing a fatty acid ester and glycerin, characterized by reacting.
The method according to claim 1, wherein the alcohol is represented by the following general formula (1).
R-OH (1)
(R represents an alkyl group having 1 to 10 carbon atoms.)
3. The method according to claim 1, wherein R in the general formula (1) is an alkyl group having 1 to 4 carbon atoms.
Oils and fats are composed of one or a mixture of two or more selected from soybean oil, rapeseed oil, corn oil, sunflower oil, sesame oil and olive oil, or waste oils thereof. 4. The method according to any one of 3.
The method according to any one of claims 1 to 4, wherein the alcohol and fat are reacted at a molar ratio of 3: 1 to 30: 1 for 1 to 10 hours.
The method according to any one of claims 1 to 5, wherein the zinc oxide used for the solid catalyst is activated zinc white containing 80% by weight or more of zinc oxide.
The method according to any one of claims 1 to 6, wherein the alkali supported on zinc oxide used for the solid catalyst is at least one metal selected from Group 1 or Group 2 metals.
The method according to claim 7, wherein the first and second group metals are at least one selected from Li, Na, K, Ca, Ba.
The method according to any one of claims 1 to 8, wherein the supported amount of alkali with respect to zinc oxide used for the solid catalyst is 1 to 20% by weight.
The method according to any one of claims 1 to 9, wherein the alkali used for the solid catalyst is produced from a soluble alkali salt.
The method according to claim 10, wherein the soluble alkali salt is a fluoride or nitrate compound of Group 1 and Group 2 metals.
The method according to any one of claims 1 to 11, wherein the alkali used in the solid catalyst is supported on zinc oxide by an impregnation method.
The method according to claim 1, wherein the solid catalyst is activated in advance.
The method according to claim 13, wherein the solid catalyst is activated by calcination in air at 300 to 700 ° C for 2 to 10 hours.
The method according to claim 14, wherein the method is used for the reaction immediately after the temperature is lowered to room temperature after firing.
Biodiesel containing a fatty acid ester produced by the method according to claim 1.
Solid catalyst used in the method according to any one of claims 1 to 15.