KR101446018B1 - Antioxidant composition for biodisel - Google Patents

Abstract

The present invention relates to an antioxidant composition for biodiesel, and to an antioxidant composition having improved oxidation efficiency. The antioxidant composition for biodiesel includes a hydroquinone-base antioxidant, one or more base additive selected from triethylene tetra amine and triethylene pentamine. The antioxidant composition according to the present invention has an excellent effect of extremely increasing oxidation stability compared with independently using of an oxidation stabilizer.

Description

ANTIOXIDANT COMPOSITION FOR BIODISEL [0002]

The present invention relates to an antioxidant composition for biodiesel, and relates to an antioxidant composition having improved oxidation efficiency.

Bio-fuels, which have recently been attracting attention as a clean alternative energy source, are environmentally friendly fuels that substitute existing fossil fuels due to excessive dependence on fossil fuels, such as coal and oil, and environmental pollutants. .

Biodiesel is made from renewable bio-resources such as vegetable oils such as rapeseed oil, soybean oil, coconut oil, palm oil, sunflower oil, rice bran oil, palm oil and animal preservation such as waste cooking oil and waste oil. Biodiesel can replace diesel in its own right and is used for existing light oil passenger cars and van without any engine modifications.

 In general, the natural stability of biodiesel varies greatly depending on the content of natural unsaturated fatty acids. Biodiesel is easily degraded by autoxidation of unsaturated fatty acids and is an additive for maintaining the cleanliness of the engine Additives such as a clean dispersant, an antioxidant, a corrosion inhibitor, and a low-temperature fluidity improving agent.

As antioxidants developed so far, natural antioxidants include tocopherol, ascorbic acid, and beta-carotene. Synthetic antioxidants are mainly hydroxy-substituted hydroxy groups, Butylated hydroxyanisole, butylated hydroxytoluene, Tertiary butyl hydroquinone, and propyl gallate.

Hydroxyanisole substituted with dibutyl hydroquinone and butyl group has been reported by L. Zhou et al. As a byproduct such as dibutyl hydroquinone, which is a byproduct, and the yield is low, 9 (2008) 2274-2277).

However, it is still required to improve the environmentally friendly method because of the inconsistency in using antioxidants produced in a way that is environmentally burdensome to biodiesel, which is introduced to reduce environmental burden due to low yield and high environmental burden.

In this regard, Applicant has filed a method for manufacturing 2-t-butyl hydroquinone, which is an antioxidant for improving the oxidation stability of biodiesel, in Korean Patent Laid-Open Publication No. 10-2013-0051653 (May 31, 2013).

Korean Patent Laid-Open Publication No. 10-2013-0051653 (May 31, 2013)

L. Zhou. et al. Catalysis Communications 9 (2008) 2274-2277

The present invention provides an antioxidant composition for further improving the oxidizing power of biodiesel.

The inventors of the present invention have developed a hydroquinone-based antioxidant as an antioxidant for improving the oxidation stability of biodiesel, and compared with the case of using hydroquinone-based antioxidant alone, The present invention has been completed.

In order to achieve the above object, the present invention relates to an antioxidant composition for biodiesel comprising a hydroquinone antioxidant and at least one basic additive selected from triethylenetetraamine and triethylenepentamine.

The antioxidant composition according to the present invention has an excellent effect of significantly improving the oxidation stability as compared with the case where the antioxidant is used alone.

Hereinafter, one embodiment of the present invention will be described in more detail.

The present inventors have studied to increase the oxidation stability of biodiesel, and as a result, they have developed a hydroquinone-based antioxidant having excellent oxidation stability against biodiesel, and have found that by mixing specific additives that have not been used in conventional biodiesel, The inventors of the present invention have found that the oxidation stability is significantly improved as compared with the case of using the hydroquinone antioxidant alone. As a result of studies by the present inventors with the above specific additives, it has been found that when one or more basic additives selected from triethylenetetraamine and triethylenepentaamine are contained, oxidation stability is higher than that when other types of basic additives or acidic additives are mixed And it was confirmed that it was greatly improved.

One embodiment of the present invention is an antioxidant composition for biodiesel comprising a hydroquinone antioxidant and at least one basic additive selected from triethylenetetraamine and triethylenepentamine.

In one embodiment of the present invention, the hydroquinone antioxidant may be any one or a mixture of two or more selected from t-butylhydroquinone, di-t-butylhydroquinone and t-butylhydroanisole.

In one embodiment of the present invention, the hydroquinone-based antioxidant may be one prepared by the method described in Korean Patent Application No. 10-2013-0051653 filed by the present applicant.

Specifically, the process for preparing 2-tert-butylhydroquinone according to the present invention comprises

a) adding and stirring hydroquinone and phosphoric acid to an organic solvent;

b) adding 2-tert-butanol or isobutene to the reaction mixture in the above step to react;

c) separating and recovering the unreacted hydroquinone by filtering the solid of the reaction mixture in the above step;

d) separating the phosphoric acid from the reaction mixture of the step;

e) separating and purifying the product, 2-ter-butyl hydroquinone and the remaining hydroquinone, from the phosphoric acid-separated reaction mixture in the above step.

The method may further comprise the step of reusing the phosphoric acid recovered in step d), hydroquinone recovered in step c) and one or more recovered hydroquinone recovered in step e), prior to step a) To e). ≪ / RTI >

The tert-butylhydroxyanisole used in the present invention may be prepared by reacting 2-tert-butyl hydroquinone prepared as described above with dimethyl cellate. Specifically, tert-butylhydroxyanisole is prepared by adding dimethylsulfate to 2-tert-butylhydroquinone prepared according to the present invention in an organic solvent, stirring the mixture for a predetermined period of time, adding a base such as sodium hydroxide Can be obtained.

In one embodiment of the present invention, the antioxidant: basic additive may be contained in a weight ratio of 1: 0.5 to 1.5. It is possible to exhibit the most excellent oxidation stability at the above content ratio, and if the content of the basic additive exceeds 1.5 weight ratio, the oxidation stability may be lowered.

In one embodiment of the present invention, the antifouling composition may be used in an amount of 0.001 to 2% by weight based on biodiesel. When the content is less than 0.001% by weight, the effect is insignificant. If the content is more than 2% by weight, the effect may not be increased. Therefore, it may be economical to use the content within the above range.

In one embodiment of the present invention, the above-mentioned antisun agent composition may satisfy the following formulas (1) and (2).

[Formula 1]

? AO = (AO _ba - AO _i ) / AO _i x 100

(%), AO _ba is the oxidation stability (hr) of the biodiesel measured after the basic additive is added, AO _i is the oxidation stability (hr) of the biodiesel measured after the addition of the basic additive, And the oxidation stability (hr) in the case of charging.

[Formula 2]

50%?? AO? 200%

(Where AO is oxidation stability efficiency (%)).

The antioxidant composition according to the present invention can satisfy the oxidation stability efficiency range of Formula 2. When the oxidation stability efficiency is less than 50%, the efficiency of cost increase is not significantly improved as compared with the case where the antioxidant is used alone have.

More specifically, in the first aspect of the present invention, the antioxidant is t-butylhydroquinone, the basic additive is any one selected from triethylenetetraamine, triethylenepentaamine, or a mixture thereof, and the antioxidant: basic additive 1: 1 ~ 1.5 weight ratio.

The second aspect of the present invention is characterized in that the antioxidant is t-butylhydroanisole, the basic additive is any one selected from triethylenetetraamine, triethylenepentamine, or a mixture thereof, and the antioxidant: basic additive 1: 0.5 To 1.5 weight ratio.

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

1) Oxidation stability evaluation

Measuring instrument: Rancimat 743 (Metrohm Herisau, Switzerland)

Antioxidants: 250, 500, 750 ppm

Measuring temperature: 110 占 폚

Air flow: 10L / h

[Production Example 1]

Preparation of 2-tert-butylhydroquinone (t-Butylhydroquinone) using hydroquinone and butanol

66 g (0.6 mol) of hydroquinone is placed in a mixture of 240 ml of 85% phosphoric acid and 240 ml of P-xylene, and the reaction solution is heated to 110 ° C and stirred. To the reaction mixture, 60 ml of t-butanol (t-BuOH) is added dropwise over 1 hour. The mixture was stirred at room temperature for 1 hour and then cooled to room temperature, and the precipitated solid hydroquinone was separated by filtration. The phosphoric acid layer of the filtrate after filtration is separated and reused. The separated P-xylene layer is cooled to room temperature and the precipitated solid is filtered. The filtered solid is partially dissolved using an aqueous solution of sodium hydroxide (10.3 g of caustic soda / 100 ml of water). The reaction solution was filtered to remove insoluble components, and 36 g of solid di-t-butyl hydroquinone (Crude yield: 35%, purity: 94%) was obtained. The filtrate obtained by filtration was neutralized with concentrated hydrochloric acid, and the precipitated solid was filtered and dried to obtain 50 g of a solid (Crude yield 50%, purity 92%). The obtained solid was recrystallized with P-xylene to obtain 40 g of solid 2-tert-butylhydroquinone (yield: 40%, purity: 99%).

Molecular weight: Theoretical value M = 166, Experimental value M = 166

Elemental analysis: Theoretical values C ₁₀ H ₁₄ O ₂ , C 72.26, H 8.49, C 71.83, H 8.43,

^{1 H NMR (300 MHz, CDCl} 3) 1.36 (d, 9H, J = 3.30Hz), 6.52 (d, 2H, J = 1.65Hz), 6.75 (t, 1H, J = 1.80Hz), 10.10 (s, 1H), < / RTI > 11.20 (s, 1H)

[Production Example 2]

Synthesis of tert-butylhydroxyanisole (t-Butylhydroanisole)

50 g (0.3 mol) of 2-tert-butylhydroquinone is added to a mixed solution of 160 ml of n-hexane and 30 ml of distilled water and stirred for 20 minutes. To the mixture was added 45.4 g (0.36 mol) of dimethyl sulfate (Dimethyl sulfate). After the addition, the mixture is stirred for 20 minutes, and then 16.8 g of sodium hydroxide is dissolved in 20 ml of H ₂ O, and the solution is slowly added dropwise to the above mixed solution over 1 hour. When added dropwise, the temperature should not exceed 50 ℃. The mixture is stirred at room temperature for 1 hour. The reaction solution is neutralized with an aqueous solution of 50% sulfuric acid (H ₂ SO ₄ ), then the n-hexane layer is extracted, and water is removed by adding anhydrous magnesium sulfate. The precipitated solid was filtered (Crude yield: 96%, purity: 89%) and recrystallized using n-hexane. The precipitated solid was filtered and dried to obtain 45 g of solid tert-butyl (Yield: 84%, purity: 99%).

Molecular weight: theoretical value M = 180, experimental value M = 180; Elemental analysis: Theoretical values C ₁₁ H ₁₆ O ₂ , C 73.30, H 8.95, C 73.39, H 8.89,

^{1 H NMR (300 MHz, CDCl} 3) 1.41 (d, 9H, J = 9.30Hz), 3.72 (s, 3H), 6.60 (d, 2H, J = 1.50Hz), 6.86 (t, H, J = 2.80 Hz), < / RTI > 10.32 (s, H)

[Example 1] Measurement of oxidation stability of hydroquinone antioxidant

250ppm, 500ppm and 750ppm of the synthesized antioxidants were added to the biodiesel, and the oxidation stability of the biodiesel was confirmed according to the amounts of the added antioxidants.

BD 100 extracted from waste cooking oil was used for biodiesel.

The hydroquinone antioxidants prepared in Preparation Examples 1 to 3 were used.

Table 1. Oxidative stability according to the amount of hydroquinone antioxidant added

(TBHA; t-butylhydroanisole, DTBHQ; di-t-butylhydroquinone, TBHQ; t-butylhydroquinone)

As shown in Table 1, the oxidation stability of the hydroquinone-based antioxidant was found to be higher than 500 ppm, the oxidation stability of the t-butyl hydroquinone compound was high (20.7 hours), and di-t-butyl hydroquinone The t-butyl hydroanisole (7.4 h) compound had a similar oxidation time.

As a result of the measurement at 250 ppm and 750 ppm, the oxidation stability was not increased proportionally as the amount of the antioxidant was increased.

[Examples 2 to 7] Measurement of oxidation stability according to addition amount of basic additive to t-butylhydroquinone

Triethylenetetramine (TETA), triethylenetetraamine (TETA), and triethylenepentaamine (TEPA) were added to t-butylhydroquinone (TBHQ) antioxidant with excellent oxidation stability in the antioxidant for biodiesel, And the oxidation stability improvement effect according to the blending ratio was analyzed. The results are shown in Table 2 below.

[Comparative Examples 1 to 6] Measurement of oxidation stability according to the amount of acidic additive added to t-butylhydroquinone

Tartanic acid and succinic acid were added to t-butyl hydroquinone antioxidant with excellent oxidation stability in biodiesel oxidation inhibitor, and the oxidation stability improvement effect was analyzed according to the mixing ratio of t-butyl hydroquinone antioxidant.

The results are shown in Table 2 below.

Table 2. Oxidative stability of t-butylhydroquinone antioxidant according to addition amount of base or acid additive

As shown in Table 2, the addition of 250 ppm, 500 ppm and 750 ppm of acid or basic additives to 500 ppm of TBHQ (t-Butylhydroquinone) as an antioxidant resulted in oxidation stability of TBHQ (t-Butylhydroquinone) 250 ppm, 500 ppm and 750 ppm of triethylenetetraamine (TETA) were added, respectively. The addition of 250 ppm, 500 ppm and 750 ppm of triethylenepentaamine (TEPA) Stability improvement effect.

In the case of the acidic additives, 250 ppm, 500 ppm and 750 ppm of tartanic acid were added to 500 ppm (t-Butylhydroquinone) TBHQ (20.7 hours), which is an antioxidant, to induce oxidation for 26.8-27.5 hours. Succinic acid ) Had an oxidation stability of 17.9 ~ 22.8 hours, which did not affect the oxidation stability of acidic additives.

[Examples 8 to 13] Measurement of oxidation stability according to the amount of basic additive added to t-butylhydroanisole

Triethylenetetramine (TETA), triethylenetetramine (TEPA) and triethylenepentaamine (TEPA) were added to t-butylhydroanisole (TBHA), an antioxidant for biodiesel, And the oxidation stability improvement effect was analyzed. The results are shown in Table 3 below.

[Comparative Examples 7 to 12] Measurement of oxidation stability of t-butyl hydroanisole as an antioxidant for biodiesel according to the addition amount of acidic additives

Tartanic acid and succinic acid were added to t-butylhydroanisole (TBHA, t-Butylhydroanisole), an antioxidant for biodiesel, and the oxidation stability was improved according to the compounding ratio of t-butylhydroanisole Respectively.

Table 3. Oxidation stability of t-butyl hydroanisole and propyl gellate antioxidant according to the addition amount of basic additive

Butyl hydroanisole (TBHA) as an antioxidant was added 250 ppm, 500 ppm and 750 ppm of triethylenetetramine (TETA) to the oxidation stability of the existing t-butylhydroanisole The oxidation induction was 13.5 ~ 21.8 hours at 7.4 hours, and the oxidation stability of triethylenepentaamine (TEPA) was 12.1 ~ 20.3 hours.

In the case of the acidic additive, 250 ppm, 500 ppm and 750 ppm of tartanic acid were added to t-butylhydroanisole (TBHA, t-butylhydroanisole) for oxidation for 9.2-10.3 hours, Succinic acid) had an oxidation stability of 7.2 ~ 8.3 hours, which did not affect the oxidation stability of acidic additives.

Claims (8)

An antioxidant composition for biodiesel comprising a hydroquinone antioxidant and one or more basic additives selected from triethylenetetraamine and triethylenepentamine. The method according to claim 1,
Wherein the hydroquinone antioxidant is any one or a mixture of two or more selected from t-butyl hydroquinone, di-t-butyl hydroquinone and t-butyl hydroanisole. The method according to claim 1,
Wherein the antioxidant: basic additive is contained in a weight ratio of 1: 0.5 to 1.5. The method of claim 3,
Wherein the antifouling composition is used in an amount of 0.001 to 2 wt% based on the biodiesel. 5. The compound according to any one of claims 1 to 4,
Wherein the composition for an antioxidant composition satisfies the following formulas (1) and (2).
[Formula 1]
? AO = (AO _ba - AO _i ) / AO _i x 100
(%), AO _ba is the oxidation stability (hr) of the biodiesel measured after the basic additive is added, AO _i is the oxidation stability (hr) of the biodiesel measured after the addition of the basic additive, And the oxidation stability (hr) in the case of charging.
[Formula 2]
50%?? AO? 200%
(Where AO is oxidation stability efficiency (%)). 6. The method of claim 5,
Wherein the antioxidant is t-butyl hydroquinone,
The basic additive is any one selected from triethylene tetramine, triethylene pentaamine, or a mixture thereof,
Antioxidant: basic additive 1: 1 to 1.5 weight ratio. 6. The method of claim 5,
Wherein the antioxidant is t-butyl hydroanisole,
The basic additive is any one selected from triethylene tetramine, triethylene pentaamine, or a mixture thereof,
Antioxidant: basic additive 1: 0.5 to 1.5 weight ratio. A biodiesel fuel comprising an antioxidant composition according to any one of claims 1 to 4.