JP2009057510A - Stabilized bio-diesel fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart oxidation stability, storage stability, and thermal resistance stability to a bio-diesel fuel, to prevent the trouble caused by a gum-like substance formed by the oxidation polymerization of a fuel in an engine or a fuel tank, and to prevent the deterioration of automobile parts such as a fuel hose by using an antioxidant which can be easily and homogeneously mixed with a bio-diesel fuel being liquid at ordinary temperature and used in a cold district with less uncertainty. <P>SOLUTION: A stabilized bio-diesel fuel is obtained by adding a specified quinoline-based or paraphenylenediamine-based compound to a bio-diesel fuel as an antioxidant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stabilized biodiesel fuel.

  In recent years, biomass energy has attracted attention due to global warming due to an increase in carbon dioxide and acid rain due to exhaust gas. Biofuels are becoming carbon-neutral fuels, and their use in automobile fuels is expanding worldwide as a measure to reduce carbon dioxide emissions and fossil fuel consumption. In particular, biodiesel fuel is an alternative fuel for light oil that can operate a diesel engine by methyl esterifying animal or vegetable oil or waste edible oil. However, since biodiesel fuel inherits the characteristics of fats and oils as it is, it is more susceptible to oxidative degradation than light oil. The problem that biodiesel is oxidatively deteriorated to generate carboxylic acid and corrodes the fuel hose, and the gum-like substance generated by oxidative polymerization of biodiesel causes various troubles in the fuel tank and engine. There are known problems.

As one of such measures, use for various antioxidants has been proposed. For example, the use of various phenolic compounds has been proposed. (Patent Document 1) However, when these compounds are mixed with biodiesel fuel that is liquid at room temperature, they are solid at room temperature, or the viscosity is remarkably high even if it is liquid. It is difficult to achieve this, and defects such as the occurrence of anxiety such as precipitation at low temperatures, especially in cold regions, are predicted. Therefore, stabilization with an antioxidant that is a liquid substance at room temperature and hardly solidifies even when encountered at low temperatures is desired.
JP 2006-283028 A

  The object of the present invention is to use an antioxidant that can be easily mixed homogeneously when mixed with biodiesel fuel that is liquid at room temperature and has less anxiety for use in cold regions. It is an attempt to solve the above problem. Furthermore, the present invention intends to impart oxidation stability to biodiesel fuel produced from a wide variety of oil types, thereby imparting storage stability and heat stability. In addition to preventing oxidative deterioration, it is intended to prevent troubles caused by gum-like substances generated by oxidative polymerization of fuel in engines and fuel tanks, as well as prevent deterioration of automobile parts such as fuel hoses. .

  As a result of various studies, the present inventors have found that the above-described object can be achieved by adding a specific quinoline-based or paraphenylenediamine-based amine antioxidant to biodiesel fuel as an antioxidant, The present invention has been completed.

  According to the stabilized biodiesel fuel according to the present invention, by providing oxidation stability, storage stability and heat stability are increased, and as a result, oxidative polymerization of fuel in an engine or a fuel tank. This prevents the occurrence of troubles caused by the gum-like substances generated by the above-mentioned and prevents the deterioration of automobile parts such as fuel hoses.

  The raw material for biodiesel fuel in the present invention includes vegetable oils such as rapeseed oil, sesame oil, soybean oil, corn oil, sunflower oil, coconut oil, safflower oil, peanut oil, cottonseed oil, linseed oil, and mustard oil, beef fat, pork Fatty acid alkyl esters obtained from fatty acid derivatives such as animal oils and fats such as oil, whale oil and fish oil, and these waste cooking oils and dark oils, monoglycerides, diglycerides and free fatty acids obtained in the production process of these fats and oils Biodiesel fuel can be mentioned, but is not limited to this. Moreover, general diesel fuel may be mixed with biodiesel fuel.

で表されるキノリン系化合物の誘導体としては、２，２，４−トリメチル１，２−ジヒドロキノリン、または同誘導体の重合度が２〜５である重合体、好ましくは、６−エトキシ２，２，４−トリメチル−１，２−ジヒドロキノリンが挙げられる。また式（ＩＩ）：

で表されるパラフェニレンジアミン系化合物としては、式（ＩＩ）においてＲ_１が炭素数１〜８のアルキル基またはフェニル基、Ｒ_２は炭素数３〜１０のアルキル基の化合物、好ましくは、Ｒ_１がフェニル基、Ｒ_２が炭素数３、４、６、または８の化合物、より好ましくは、Ｒ_１がフェニル基で、Ｒ_２が炭素数８のアルキル基である化合物である。 Formula (I):

As a derivative of a quinoline compound represented by the formula: 2,2,4-trimethyl 1,2-dihydroquinoline, or a polymer having a degree of polymerization of 2 to 5, preferably 6-ethoxy 2,2 , 4-trimethyl-1,2-dihydroquinoline. Formula (II):

In the formula (II), R ₁ is an alkyl group or phenyl group having 1 to 8 carbon atoms, R ₂ is an alkyl group having 3 to 10 carbon atoms, preferably R 1 ₁ is a phenyl group, R ₂ is a compound having 3, 4, 6, or 8 carbon atoms, more preferably a compound in which R ₁ is a phenyl group and R ₂ is an alkyl group having 8 carbon atoms.

  The amount of the quinoline compound represented by the formula (I) and the paraphenylenediamine compound represented by the formula (II) added to the biodiesel fuel is usually 500 to 3000 ppm, preferably 1000 to 2500. It is. Even if it exceeds 3000 ppm, the improvement of the effect commensurate with the increase of the addition amount is small, and if it is less than 500 ppm, a sufficient antioxidant effect cannot be obtained.

  Hereinafter, the present invention will be described more specifically with reference to test examples. However, the present invention is not limited to these test examples.

[Test example]
As shown in the following Table 1, as biodiesel fuel, the following compounds are respectively added in predetermined amounts to biodiesel fuel A and biodiesel fuel B prepared from rapeseed oil, which are prepared from waste edible oil. Each antioxidation effect was measured by the Rancimat method (EN14112).
Compound A: N- (1-methylheptyl) -N′-phenylenediamine (the present compound),
Compound B used: 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (compound of the present application),
Compound C used: 2,6-di-tert-butyl-4-methylphenol (BHT) (control compound),
Compound D used: 2,2′-methylenebis [6-tert-butyl-4-methylphenol] (MBP) (control compound),
Compound E: tert-butyl hydroquinone (TBH) (control compound)

Outline of the Rancimat method About 3 g of a sample is put in a reaction vessel, heated to 110 ° C., clean air is sent into it, volatile decomposition products are collected in water, and the conductivity of the collected water changes abruptly. Measure the time to the bending point (induction time). That is, the induction time is determined by measuring the change over time of the amount of decomposition products (formic acid and acetic acid are the main components) produced by oxidation of the biodiesel fuel that is the sample. This value is recognized as being a good indicator for evaluating oxidation stability because it is recognized to be linked to other parameters (peroxide value, kinematic viscosity, acid value, etc.) related to oxidation of biodiesel fuel. Used for testing. In addition, in the standard (EN14214) regarding biodiesel fuel in Europe, the reference value by this method is set to 6 hours or more.

  The evaluation results are shown in Table 1 below.

  From the results in Table 1, it can be seen that the induction time is uniformly extended by adding the antioxidant. In particular, the compound A according to the present invention has a longer induction time and higher oxidation stability than the conventional phenolic antioxidants C, D and E. The performance of the compound B according to the present invention was also confirmed. Further, C, D, and E are solid substances, whereas the compounds A and B according to the present invention are liquid substances, which are advantageous in addition work when used as a fuel additive, and troubles due to undissolved parts are also caused. Can be prevented. It can be expected to be used as a stable fuel by preventing the oxidation of biodiesel fuel.

  In the stabilized biodiesel fuel according to the present invention, the compound used for oxidation prevention is liquid at room temperature, so that homogeneous mixing can be easily performed and there is no anxiety for use in cold regions. , Industrially useful.

Claims (3)

Formula I:

Or a derivative of a quinoline compound represented by
Formula II:

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms or a phenyl group, and R ₂ represents an alkyl group having 3 to 10 carbon atoms.)
A stabilized biodiesel fuel comprising at least one compound comprising a paraphenylenediamine compound represented by the formula:   2. The stabilized bio of claim 1, wherein the compound is N- (1-methylheptyl) -N′-phenylenediamine or 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline. Diesel fuel.   The stabilized biodiesel fuel according to claim 1 or 2, comprising 500 ppm to 2000 ppm of the compound.