RU2723548C1 - Method of producing high-octane additive by hydrogenation of furfural and furfuryl alcohol - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to a method of producing 2-methylfuran by selective hydrogenation of furan derivatives – furfural and/or furfuryl alcohol. Method involves hydrogenation of furfural and/or furfuryl alcohol in the presence of catalyst containing 15 wt% molybdenum carbide modified with nickel metal with molar ratio Ni/Mo from 0.1 to 0.5, the rest is carbon carrier of Sibunit type, hydrogenation is carried out in a batch plant at temperature of 150 °C, a hydrogen pressure of 6.0 MPa, a stirring speed of 1,800 rpm, reaction time of 4 hours using a solution with volumetric content of furfural or furfuryl alcohol in isopropanol of 3.5 vol% or in a flow type plant in the absence of a solvent at temperature of 160–200 °C, hydrogen pressure of 5.0 MPa, feed rate of 3–6 ml/h and hydrogen flow rate of 300–600 ml/min in the presence of said catalyst.EFFECT: novel method of producing 2-methylfuran with high output in selective hydrogenation of furfural and/or furfuryl alcohol; obtained 2-methylfuran can be used to increase octane number of gasoline.1 cl, 2 dwg, 7 tbl, 10 ex

Description

The invention relates to the field of development of a method for producing high-octane additives - 2-methylfuran by hydrogenation of furfural and / or furfuryl alcohol.

With world production of 300 thousand tons / g, furfural is the feedstock for many chemicals. One of the most common products of furfural processing by selective hydrogenation is furfuryl alcohol.

Recently, furan derivatives are considered as an alternative “bio” raw material with a wide range of uses. One of the components obtained by hydrogenation of furfural or furfuryl alcohol can be 2-methylfuran (methylfuran, sylvan), which is formed during the hydrogenolysis of the hydroxyl group of furfuryl alcohol or the aldehyde group of furfural.

Sylvan has already found widespread use as a solvent in the manufacture of antimalarial drugs (chloroquine), N- and S-heterocycles, and functionally substituted aliphatic compounds. Since the electron-donating methyl group of methylfuran increases the reactivity of the furan ring, in position 5 it is easily alkylated and allows it to be used as a feedstock to create long hydrocarbon chains in the production of diesel or jet fuel.

In addition, methylfuran is considered as a promising high-octane additive to gasoline [EP 0082689, C10L 1/02, 12/17/1982], since it has comparable values in chemical properties with traditional gasoline, while its production is renewable, and its use in a mixture with fossil fuel reduces the amount of air emissions.

In the patent [EP 0082689, C10L 1/02, 12/17/1982] gasoline is used with a research octane higher than 85, suitable for use in internal combustion engines. The results showed that the addition of 10 vol. % 2-methylfuran increases the research octane of gasoline containing olefins from 92.7 to 96.3 points.

Conventional methods for preparing methylfuran production catalysts during hydrogenation with hydrogen include the use of copper and chromium compounds as precursors.

An advanced gas-phase process is carried out by feeding furfural to the evaporator system at 120 ° С, followed by hydrogenation of furfural gas with hydrogen on CuCr catalysts and condensation of the resulting furfuryl alcohol with a subsequent increase in the reaction temperature from 120 ° С (furfuryl alcohol production temperature) to 250 ° С, which allows to obtain 2-methylfuran with a yield of up to 90%.

In the 1948 patent [US 2456187, С07С 29/145, 12/14/1948] furfural was hydrogenated at a temperature of 170 ° C and a pressure of 0.4 MPa with a furfural feed rate of 90 l / h using pure copper obtained by reduction of copper oxide at 140 ° C. The conversion was 100%, the yield of 2-methylfuran was 40%, the yield of furfuryl alcohol was 60%. At a lower temperature (140 ° C), methylfuran did not form. If furfuryl alcohol was used as the feedstock instead of furfural, its complete conversion to methylfuran at 170 ° C was observed.

Manly et al. [DG Manly, A.R. Dunlop, Catalytic Hydrogenation. I. Kinetics and Catalyst Composition in the Preparation of 2-Methylfuran, The Journal of Organic Chemistry, 23 (1958) 1093-1095] for the liquid-phase process used the method of modifying copper chromite with calcium oxide according to the Adkins method [R. Connor, K. Folkers, N. Adkins, The preparation of copper-chromium oxide catalysts for hydrogenation, Journal of the American Chemical Society, 54 (1932) 1138-1145.]. The CuO catalyst (46%) - Cr ₂ O ₃ (50%) - CaO (4%) allowed to obtain 93.1% methylfuran in the hydrogenation of furfural at a temperature of 200 ° C.

At a temperature of 250 ° C, a furfural volumetric rate of 0.13 h ^-1 , a hydrogen / aldehyde ratio of 7.8, an experiment duration of 5.5 hours using a catalyst with a Cu: Cr: Mg atomic ratio of 1: 1.05: 0 04 [JGM Bremner, RKF Keeys, 202. The hydrogenation of furfuraldehyde to furfuryl alcohol and sylvan (2-methylfuran), Journal of the Chemical Society (Resumed), (1947) 1068-1080], up to 87% sylvan was observed.

In gas-phase reactions, methylfuran can be obtained with a yield of up to 69.7% using the catalyst CuO (46.9%) - Cr ₂ O ₃ (46%) - MnO ₂ (3.3%) - BaCrO ₄ (3.6%) [US 6479677, C07D 307/06, 11/12/2002], obtained by the Adkins method for hydrogenation of furfural at a temperature of 175 ° C, the feed rate of the furfural-hydrogen gas mixture was 1.5 ml / min, the molar ratio of hydrogen to furfural was 2 .

In the hydrogenation of furfuryl alcohol at 200 ° C, a hydrogen feed rate of 20 l / h and a furfural feed rate of 0.5 mol / h, 80% methylfuran was obtained using Fe (10%) - Cu (90%) catalyst [R.M. Lukes, C.L. Wilson, Reactions of Furan Compounds. Xi. Side Chain Reactions of Furfural and Furfuryl Alcohol over Nickel-Copper and Iron-Copper Catalysts 1, Journal of the American Chemical Society, 73 (1951) 4790-4794].

Methylfuran in 87% yield was obtained using a commercial catalyst Cu (59): Zn (33): Al (6): Ca (1): Na (1) (atomic ratio), reduced at 270 ° C, [H.- Y. Zheng, Y.-L. Zhu, V.-T. Teng, Z.-Q. Bai, C.-H. Zhang, H.-W. Xiang, Y.-W. Li, Towards understanding the reaction pathway in vapour phase hydrogenation of furfural to 2-methylfuran, Journal of Molecular Catalysis A: Chemical, 246 (2006) 18-23] in the hydrogenation of furfural. The reaction used a pressure of 0.1 MPa, a catalyst load of 0.3 h ⁻¹ , a molar ratio of hydrogen to furfural equal to 25, and a process temperature of 250 ° C. Under the same conditions, but using furfuryl alcohol as a reagent, the yield of 2-methylfuran was 92.7%.

However, it is worth noting that the considered catalysts are deactivated under process conditions. One of the main reasons for the deactivation of copper and chromium catalysts during furfural hydrogenation is the formation of coke deposits, strong adsorption of reaction products on the catalyst surface, change in the oxidation state of active centers and sintering of metal particles. In addition, chromium-based compounds are toxic, which is another factor for not using them in furfural conversion.

Methods for preparing noble metal catalysts make it possible to obtain catalyst systems devoid of the disadvantages of copper based catalysts. However, noble metals are less selective in the formation of 2-methylfuran, and often lead to the formation of furfuryl alcohol or hydrogenation products of the furan ring. In the work [S. Nguyen-Huy, J.S. Kim, S. Yoon, E. Yang, J.H. Kwak, M.S. Lee, K. An, Supported Pd nanoparticle catalysts with high activities and selectivities in liquid-phase furfural hydrogenation, Fuel 226 (2018) 607-617] by reaction in a 100 ml stainless steel high pressure reactor containing 1 g furfural and 20 ml of isopropanol at a hydrogen pressure of 2 MPa, a reactor temperature of 180 ° C and a stirring speed of 600 rpm for 5 hours, it was found that a Pd (5%) / C sample deposited on carbon leads to the formation of only 44% 2- methylfuran.

At the same time, it was shown that Pd, supported on other carriers, does not form 2-methylfuran even in small amounts. A similar behavior of catalysts based on Pt and Ru was observed in [E. Makela, R. Lahti, S. Jaatinen, H. Romar, T. Hu, R.L. Riigipep, U. Lassi, R. Karinen, Study of Ni, Pt, and Ru Catalysts on Wood-based Activated Carbon Supports and their Activity in Furfural Conversion to 2-Methylfuran, ChemCatChem, 10 (2018) 3269-3283]. It was found that the maximum yield of 2-methylfuran upon hydrogenation of furfural at 230 ° C and a pressure of 4 MPa on Pt (3%) / C and Ru (3%) / C catalysts was 48% and 40%, respectively.

Thus, the use of noble metal catalysts is ineffective for the production of sylvan. In addition, the high cost of precious metals makes the use of these catalytic systems less economically feasible.

Recently, chromium-free transition metal catalysts have been developed to produce 2-methylfuran. The catalysts obtained by such methods have a low cost, good catalytic activity and low toxicity. Thus, liquid-phase hydrogenation of furfural to 2-methylfuran at 230 ° C and a hydrogen pressure of 4 MPa allows to obtain up to 48.9% of 2-methylfuran using a Ni (10%) / C catalyst [S.K. Jaatinen, R.S. Karinen, J.S. Lehtonen, Liquid Phase Furfural Hydrotreatment to 2-Methylfuran with Carbon Supported Copper, Nickel, and Iron Catalysts, ChemistrySelect, 2 (2017) 51-60].

Hydrogenation of a 10% solution of furfural in isopropanol in the temperature range of 100-200 ° C and a hydrogen pressure of 6 MPa was studied in [A.A. Smirnov, I.N. Shilov, M.V. Alekseeva, S.A. Selishcheva, V.A. Yakovlev, Investigation of the effect of the composition of molybdenum-modified NiCu-containing catalysts on their activity and selectivity in the hydrogenation of furfural to produce various valuable chemicals, Industrial Catalysis, 17 (2017) 517-526] using sol-gel Ni-based catalysts prepared by sol gel method. Although the yield of 2-methylfuran did not exceed 45% even at a temperature of 200 ° C, it was found that the introduction of molybdenum into the catalyst leads to the formation of nickel-molybdenum alloys, which increase the yield of sylvan in the conditions of liquid-phase hydrogenation of furfural.

The effect of the composition of nanoporous Cu-Al-Co alloys was studied in the gas-phase hydrogenation of furfural [G.S. Hutchings, W. Luc, Q. Lu, Y. Zhou, D.G. Vlachos, F. Jiao, Nanoporous Cu-Al-Co Alloys for Selective Furfural Hydrodeoxygenation to 2-Methylfuran, Industrial & Engineering Chemistry Research, 56 (2017) 3866-3872]. It was shown that, despite weak catalyst deactivation associated with coking, a total conversion of furfural of 98.2% was achieved with a yield of 2-methylfuran of 64.9% at 240 ° C using a Cu-Al-Co nanoporous catalyst with a cobalt content of approximately 5 %

The sylvan yield of 78% was obtained by hydrogenation of furfural at 220 ° C and 4.0 MPa over a Cu-Co catalyst obtained by impregnating alumina with solutions of nitrates of the corresponding metals [S. Srivastava, G.C. Jadeja, J. Parikh, A versatile bi-metallic copper-cobalt catalyst for liquid phase hydrogenation of furfural to 2-methylfuran, RSC Advances, 6 (2016) 1649-1658]. However, such a catalyst resulted in low yields of 2-methylfuran when reused.

Recently, molybdenum carbide catalysts have become popular. An important feature of these catalysts is their ability to hydrogenate alcohol and carbonyl groups without reducing unsaturated carbon bonds and aromatic systems.

Closest in technical essence to the claimed method for producing 2-methylfuran is the method of selective hydrogenation of furfural, described in [K. Xiong, W.-S. Lee, A. Bhan, JG Chen, Molybdenum Carbide as a Highly Selective Deoxygenation Catalyst for Converting Furfural to 2-Memylfuran, 7 (2014) 2146-2149]. Selective hydrogenation of furfural was carried out in a flowing quartz reactor (internal diameter 10 mm) at atmospheric pressure using 0.64 g of Mo ₂ C catalyst with a fraction of 0.42-0.177 mm. The reaction temperature was 150 ° C. Before the reaction, the catalyst was treated with hydrogen with a total flow rate of 60 ml / min at 477 ° C for 1 h (with a heating rate of 0.185 ° C / s from room temperature). Then the temperature of the reactor was cooled to 150 ° C and the gas flow was switched from pure H ₂ to the reaction mixture (1.67 cm ³ / s), consisting of 0.24 / 2.50 / 97.26 vol. % furfural, CH ₄ , and H ₂ . This catalyst allows to achieve 60% selectivity for the formation of 2-methylfuran. The initial degree of furfural conversion is 87%, the yield of 2-methylfuran is 83%.

A common disadvantage for the prototype and all of the above methods for producing 2-methylfuran is that when using them it is not possible to achieve a high yield of furfuryl alcohol, and, in addition, a decrease in the activity of the catalyst due to the formation of carbon deposits on its surface is observed.

The technical problem to which the claimed invention is directed is the development of a high-performance method for producing 2-methylfuran by selective hydrogenation of furfural and / or furfuryl alcohol, which allows to achieve high values of the conversion of the feedstock and the yield of 2-methylfuran.

EFFECT: obtaining 2-methylfuran with a yield of over 90% by selective hydrogenation of furfural and / or furfuryl alcohol, both in the case of a process in a batch mode and in the case of a process in a flow unit without using a solvent.

The problem is solved by the method of producing 2-methylfuran by hydrogenation of furfural and / or furfuryl alcohol in the presence of a catalyst containing molybdenum carbide, and the catalyst contains 15 wt. % of the active component in the form of molybdenum in carbide form, modified with metallic nickel with a Ni / Mo molar ratio of 0.1 to 0.5, the rest is a carbon carrier of the Sibunit type. Hydrogenation is carried out on a batch unit at a temperature of 150 ° C, a hydrogen pressure of 6 , 0 MPa, stirring speed 1800 rpm, reaction time 4 hours using a solution with a volumetric content of furfural or furfuryl alcohol in isopropanol 3.5 vol. % or in a flow-type installation in the absence of a solvent at a temperature of 160-200 ° C, a hydrogen pressure of 5.0 MPa, a feed rate of 3-6 ml / h and a volumetric hydrogen rate of 300-600 ml / min in the presence of said catalyst.

To obtain 2-methylfuran, the used catalyst before reducing the selective hydrogenation of furfural and / or furfuryl alcohol is reduced in a stream of hydrogen supplied at a rate of 100 ml / min, at a temperature of 350 ° C, a pressure of 0.1 MPa for 1 hour.

The differences of the proposed method for producing 2-methylfuran in comparison with the prototype is that furfuryl alcohol can be used as the initial reagent, and the selective hydrogenation process can be carried out in two modes: in a batch mode at a temperature of 150-200 ° C, a pressure of 6.0 MPa using a solvent or in a flowing liquid-phase mode at a temperature of 160-200 ° C, a pressure of 5.0 MPa, a feed rate of furfural of 3-6 ml / h, a feed rate of hydrogen of 300-600 ml / min in the presence of 3 ml of catalyst fraction 0, 25-0.5 mm containing 15 wt. % of the active component, which is molybdenum in carbide form, modified with metallic nickel with a molar ratio of Ni / Mo from 0.1 to 0.5 and 85 wt. % carrier is a carbon carrier of the Sibunit type.

The technical result of the proposed method for producing 2-methylfuran by selective hydrogenation of furfural and / or furfuryl alcohol is provided by the following:

1. High selectivity in the formation of 2-methylfuran is ensured by the presence of two types of molybdenum carbide in the catalyst for selective hydrogenation of furfural / furfuryl alcohol: cubic fcc-MoC _1-x and hexagonal hcp-Mo ₂ C form of molybdenum carbide. Such a chemical composition of molybdenum carbide is formed after calcining the initial sample in an argon stream at a temperature of 400 ° C due to the interaction of the oxide form of molybdenum with a carbon source - citric acid, and also due to the influence of a carbon carrier. The presence of two phases of molybdenum carbide was confirmed by x-ray diffraction analysis (Fig. 1)

In FIG. 1 shows an X-ray diffraction pattern of a catalyst based on molybdenum carbide modified with nickel and deposited on Sibunit.

2. The high activity in the hydrogenation of furfural / furfuryl alcohol is due to the presence of nickel monometallic particles in the composition used for selective hydrogenation of furfural / furfuryl alcohol, while observing a molar ratio of Ni / Mo from 0.1 to 0.5 ensures an optimal distribution of metallic nickel particles over the surface of molybdenum carbide upon reduction of the sample in hydrogen at 600 ° C, which leads to a synergistic effect of high nickel activity in hydrogenation reactions and high selectivity of molybdenum carbide in the formation of 2-methylfuran. The presence of metallic nickel was confirmed by x-ray photoelectron spectroscopy. The distribution of nickel metal particles on the surface of molybdenum carbide and the carrier according to transmission electron microscopy (TEM) is shown in FIG. 2 (TEM image of a nickel-modified molybdenum carbide catalyst deposited on Sibunit).

3. The use of Sibunit as a carrier of 85 wt. % leads to an increase in the total surface of carbide catalysts from 11 m ² / g without support to 148-175 m ² / g using Sibunit, which also increases the activity of the catalyst.

Selective hydrogenation of furfural / furfuryl alcohol is carried out, in particular, at a batch unit at a temperature of 150-200 ° C, a pressure of 6.0 MPa, a stirring speed of 1800 rpm, a reaction time of 4 hours, in the presence of 60 ml of a solution with a volumetric content of furfural / furfuryl alcohol in isopropanol 3.5 vol. % in the presence of 1 g of carbide catalyst.

Selective hydrogenation is also carried out on a flow-through installation at a temperature of 160-200 ° C, a pressure of 5.0 MPa, a feed rate of furfural / furfuryl alcohol of 3-6 ml / h, a hydrogen supply of 300-600 ml / min in the presence of a carbide catalyst.

The carbide catalyst contains 15 wt. % of the active component, which is molybdenum in carbide form, modified with metallic nickel with a molar ratio of Ni / Mo from 0.1 to 0.5; and 85 wt. % carrier is a carbon carrier of the Sibunit type. Before the reaction, the catalyst is activated in a stream of hydrogen supplied at a rate of 100 ml / min, at a temperature of 350 ° C for 1 hour, which leads to an additional reduction of metal particles of Nickel.

Example 1

The preparation of 2-methylfuran was carried out in a batch reactor (autoclave) at a constant hydrogen pressure of 6 MPa and a temperature of 150 ° C, a stirring speed of 1800 rpm, a reaction time of 4 hours, using 60 ml of a reagent solution with a volume content of furfural in isopropanol 3, 5 vol. % in the presence of 1 g of catalyst.

To prepare the NiMoC / Sibunit catalyst, the required amount of ammonium molybdate, nickel nitrate, citric acid and distilled water to provide a Ni / Mo molar ratio of 0.1 to 0.5 (the molar ratio of molybdenum and nickel to carbon in the citric acid is 1: 1 ) are intensively mixed when heated to 100 ° C until the components are completely dissolved. Bring the solution to the desired concentration with distilled water. A carbon carrier, Sibunit, is impregnated with the obtained impregnation solution for moisture capacity, which is then dried in air at 100 ° C and calcined in a stream of Ar at 400 ° C (the thermal decomposition of the organic matrix is carried out with the formation of carbide phases). The resulting composite is cooled in a stream of Ar, reduced at 600 ° C in a stream of hydrogen, which leads to the formation of metallic particles of nickel, re-cooled and passivated with 1% O ₂ in argon at room temperature. Before the reaction, the catalyst is reduced in a stream of hydrogen at a temperature of 350 ° C for 1 h with a flow rate of hydrogen of 300 ml / min and a pressure of 0.1 MPa.

The performance of the selective hydrogenation of furfural at a process temperature of 150 ° C is shown in table 1. The composition of the catalysts is given without taking into account carbide carbon and carbon remaining after the decomposition of citric acid.

It is impossible to evaluate their content, since it is impossible to determine the exact ratio of cubic fcc-MoC _1-x and hexagonal hcp-Mo ₂ C forms of molybdenum, and to distinguish free carbon from Sibunit. When calculating the composition of the catalyst, the amount of metals impregnated and the amount of carrier used were taken into account.

Example 2

Similar to example 1. The catalyst contains a molar ratio of Ni / Mo equal to 1. The specific surface area according to BET is 181 m ² / year However, the yield of 2-methylfuran is only 63% with a furfural conversion close to 100%. The low yield of 2-methylfuran is due to the high content of metallic nickel, which promotes the hydrogenation of the furan ring to form tetrahydrofurfuryl alcohol and methyltetrahydrofuran.

Example 3

Similar to example 1. The catalyst contains a molar ratio of Ni / Mo equal to 0.1. The BET specific surface area of the mixed oxide is 148 m ² / g and the average pore size is 11 nm. The process of hydrogenation of furfural was carried out analogously to example 1, characterized by a process temperature of 150-200 ° C. The results of the process of hydrogenation of furfural are presented in Table 2.

With increasing reaction temperature, hydrogenation products of the furan ring appear with the formation of methyltetrahydrofuran.

Example 4

Similar to example 1. The catalyst contains a molar ratio of Ni / Mo equal to 0.1. The catalyst after the reaction was separated by filtration, washed and reused in the hydrogenation reaction of furfural under the conditions according to example 1. The conversion of furfural and the yield of 2-methylfuran after each repeated cycle are presented in table 3. According to the data obtained, the used catalyst has high stability under process conditions and can be reused.

Example 5

Similar to example 1, characterized in that instead of furfural, furfuryl alcohol is used in the initial solution. The catalyst contains a molar ratio of Ni / Mo equal to 0.1. The conversion of furfuryl alcohol was 100%, and the yield of 2-methylfuran reached 97.1%, which exceeds the yield of 2-methylfuran when using furfural under the same conditions. This is probably due to the fact that furfural is more reactive along the hydrogenation routes of the furan ring than furfuryl alcohol.

Example 6

As a comparison, a nickel-free MoC catalyst was prepared without a carrier. The preparation method is similar to example 1, but there is no stage of impregnation. The resulting solution was evaporated at 100 ° C to a viscous state. Dried at 100 ° C for 24 hours. And subjected to heat treatment according to example 1.

The specific surface area of the resulting catalyst is 11 m ² / g. The process of hydrogenation of furfural was carried out according to example 1. The conversion of furfural was 3%, the product was furfuryl alcohol.

Example 7

As a comparison, a supported MoC / Sibunit catalyst without nickel was prepared. The preparation method is similar to example 1, but there is no stage of the introduction of nickel nitrate (the molar ratio of molybdenum to carbon in citric acid corresponds to 1: 1). The specific surface area of the resulting catalyst is 11 m ² / g. The process of hydrogenation of furfural was carried out according to example 1. The resulting composite is a mixture of two types of molybdenum carbide cubic fcc-MoC _1-x and hexagonal hcp-Mo ₂ C form. After 4 hours of carrying out the process, by analogy with Example 1, the conversion of furfural is 11 mol. %, the selectivity of the formation of 2-methylfuran - 98 mol. %, which confirms the high selectivity of the carbide forms of molybdenum in the formation of 2-methylfuran, but also indicates a low activity of molybdenum carbide without metal particles of nickel.

Example 8

The catalyst is preliminarily prepared according to a method analogous to Example 1. The result is a Ni _0.1 MoC / Sibunit catalyst containing 15 wt. % of the active component, which is molybdenum in carbide form, modified with metallic nickel with a molar ratio of Ni / Mo equal to 0.1 and 85 wt. % carrier is a carbon carrier of the Sibunit type.

The process of selective hydrogenation of furfural is carried out on a flow-through installation in the absence of solvent at a temperature of 100-260 ° C, a hydrogen pressure of 5.0 MPa, a feed rate of 3-6 ml / h and a hydrogen of 300-600 ml / min, to maintain a constant ratio of raw materials to hydrogen, the mass of the catalyst is 1.7 g (3 ml, fraction size 0.25-0.5 mm). The yield data of 2-methylfuran are presented in table 4. Before the reaction, the catalyst is reduced analogously to example 1. The carbon content was calculated as the difference between the initial carbon content in the catalyst and the carbon content after the reaction for 7 hours. Carbon analysis was performed using a CHNS analyzer.

As can be seen from the data obtained, the optimal conditions for the production of 2-methylfuran is a temperature of 160-200 ° C, a hydrogen pressure of 5.0 MPa, a feed rate of 3-6 ml / h and a hydrogen of 300-600 ml / min.

When the process temperature rises above 200 degrees during the hydrogenation of furfural, a number of side processes occur, in particular the formation of 2-methyltetrahydrofuran as the main product, as well as the opening of the furan ring with the appearance of compounds such as 1-pentanol, 2-pentanol and pentane. It is also worth noting the high stability of the catalyst, which does not lose its activity during 7 hours of operation, compared with the prototype.

Example 9

Similar to example 8, characterized in that instead of furfural, furfuryl alcohol is used. The process of selective hydrogenation of furfuryl alcohol is carried out on a flow-through installation in the absence of solvent at a temperature of 100-260 ° C, a hydrogen pressure of 5.0 MPa, a feed rate of 3 ml / h and a hydrogen of 300 ml / min, a catalyst weight of 1.7 g (size fractions 0.25-0.5 mm). Data on the hydrogenation of furfuryl alcohol are presented in table 5.

In the case of using furfuryl alcohol as the starting material, the yield of 2-methylfuran is lower than when using furfural. In addition, there is a higher content of carbon deposits. This is probably due to the fact that the used furfuryl alcohol polymerizes during storage and the resulting polymer molecules block the active sites of the catalyst, reducing the yield of 2-methylfuran.

Example 10

The obtained 2-methylfuran can be used as a high-octane additive (WAT) for automotive fuels, in particular gasoline. Table 6 presents data on the effect of 2-methylfuran on the chemical properties of gasolines, grades AI-80 and AI-92. The proportion of methylfuran can be from 1 to 15 vol. % in gasoline.

The distillation characteristics of gasoline and the corresponding mixture of gasoline and 2-methylfuran (2-MF) are shown in Table 6. As can be seen, the addition of 2-methylfuran to AI-92 gasoline did not significantly affect the distillation characteristics, while the addition of 5 vol. % 2-methylfuran to AI-80 gasoline allowed to reduce the maximum boiling point from 215.30 to 159.53 ° С.

Analysis of gasolines and a mixture of gasolines with 2-methylfuran for the content of monoaromatics and polyaromatics by high-performance liquid chromatography on an Agilent 1260 instrument according to ASTM 6591-11 showed that AI-80 fuel and its mixtures with water contain 6-7% of monoaromatic compounds, then like AI-92 gasoline and its mixtures with 2-methylfuran, contain up to 28.5% of monoaromatics. Despite the fact that 2-methylfuran has an aromatic ring, it does not belong to the benzene ring, which means that sylvan has advantages over water based on benzene rings, the content of which in the fuel is limited. In addition, it is worth noting that methylfuran contains oxygen in its composition, which contributes to the afterburning of hydrocarbons and CO, which helps to reduce these harmful substances in the exhaust gases, which makes the fuel more environmentally friendly.

The octane values according to the research method (OCI) of the obtained mixtures of gasoline with 2-methylfuran were determined according to GOST 8226 at the UIT-65 installation. The research octane mixing values were calculated from the measured values of the OCI of gasolines and mixtures of 2-methylfuran with gasoline using the formula:

where OCH _cm - research octane mixing for high-octane additives;

OCHI _{gasoline + WATER} - research octane number of fuel obtained by mixing gasoline and high-octane additives;

OCHI _gasoline - research octane of the source gasoline;

ω _gasoline and ω _WATER - percentage of gasoline and high-octane additives in the resulting blend,

WATER is a high octane additive.

From the data obtained, it is seen that the best results are obtained by mixing low-octane gasoline with 2-methylfuran, which makes it possible to increase the octane number by 7-8 points. Probably, the low effect of the additive on AI-92 gasoline is due to the fact that it already contains aromatic additives, the effect of which on the fuel properties is much stronger than the effect of 2-methylfuran.

Thus, as can be seen from the above examples, the proposed method for producing 2-methylfuran by selective hydrogenation of furfural and / or furfuryl alcohol allows to obtain the target product with a high yield (more than 90 mol.%) In the liquid phase process both in the presence of a solvent and without using solvent, with high stability of the catalyst to carbon deposition. The resulting 2-methylfuran can be used as a high-octane gasoline additive. Moreover, it is most effective for gasolines with a low initial value of the octane number.

Claims (2)

1. The method of producing 2-methylfuran by hydrogenating furfural and / or furfuryl alcohol in the presence of a catalyst containing molybdenum carbide, characterized in that the catalyst contains 15 wt.% The active component in the form of molybdenum in carbide form, modified with metallic nickel with a molar ratio of Ni / Mo is from 0.1 to 0.5, the rest is a carbon carrier of the Sibunit type, and hydrogenation is carried out on a batch unit at a temperature of 150 ° C, a hydrogen pressure of 6.0 MPa, a stirring speed of 1800 rpm, a reaction time of 4 hours using a solution with a volumetric content of furfural or furfuryl alcohol in isopropanol of 3.5 vol.% or in a flow-type installation in the absence of solvent at a temperature of 160-200 ° C, a hydrogen pressure of 5.0 MPa, a feed rate of 3-6 ml / h and volumetric the hydrogen speed of 300-600 ml / min in the presence of the specified catalyst. 2. The method according to p. 1, characterized in that the used catalyst before conducting selective hydrogenation of furfural or furfuryl alcohol is activated in a stream of hydrogen supplied at a speed of 300 ml / min, at a temperature of 350 ° C, a pressure of 0.1 MPa for 1 hour .

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