WO2021170012A1 - Novel clean diesel system containing mixed oxalate - Google Patents

Abstract

A mixed oxalate used as a diesel assistant and use thereof, and a clean diesel containing the mixed oxalate. The mixed oxalate is preferably methyl ethyl oxalate mixed ester mMEO, methyl butyl oxalate mixed ester mMBO, or methyl ethyl propyl butyl oxalate mixed ester mMAO; a binary oxygen-containing clean diesel that satisfies diesel performance requirements, and a ternary clean diesel represented by methyl ethyl oxalate mixed ester mMEO-n-butyl alcohol-diesel and mMEO-fatty acid monoglyceride-diesel are developed by using the mixed oxalate. The mixed oxalate can promote the clean and efficient utilization of petroleum-based diesel, non-petroleum-based diesel, and biodiesel.

Description

New clean diesel system containing mixed oxalate Technical field

The invention belongs to the field of energy and chemical industry, and specifically relates to fuel products and fuel additives, and specifically to a new clean diesel system containing mixed oxalate esters.

Background technique

Petroleum is a non-renewable resource and the main raw material of fuel oil. my country's oil resources are scarce, and a large amount of it needs to be imported, and the import volume exceeds 70%. Gasoline and diesel are the main fuel products produced by the direct separation, cracking, reforming or hydrogenation of petroleum. The annual output of diesel exceeds that of gasoline, reaching 160 million tons.

Compared with gasoline, diesel is a high-boiling oil mainly composed of long-chain aliphatic hydrocarbons. The content of aromatic hydrocarbons and olefins is lower, and coal-based diesel is lower. Diesel engines have high power and huge demand for diesel. There is no substitute for them. Diesel engines emit serious soot emissions.

According to the data from the 2018 China Motor Vehicle Environmental Management Annual Report, the number of diesel vehicles in my country in 2017 was 19.567 million, accounting for 9.4% of the total number of vehicles, but the nitrogen oxides they emitted accounted for 70% of the total emissions of vehicles. PM2.5 exceeds 90%. Diesel vehicles are the main source of primary atmospheric particulate matter emitted by motor vehicles. Although diesel vehicle exhaust emits a large amount of hydrocarbon components, black smoke and PM2.5 seriously pollute the environment, because the compression ratio of diesel engines can reach 14-22, the thermal efficiency is 20% higher than that of gasoline, and it is close to 50%. Power diesel engines cannot yet be replaced by electricity, lithium-ion batteries, super capacitors, etc.

Because diesel has a higher flash point than gasoline, it is safer for ships, ships, tanks and other equipment. Therefore, it is of great significance to develop a clean and safe new diesel system to solve the problem of diesel fuel supply, low-cost clean production and safe use of diesel additives.

In order to alleviate the dependence on petroleum and solve the serious pollution of diesel, finding diesel substitutes or adding oxygen-containing additives to diesel to produce clean diesel are the two main directions of attack, as well as the important direction of new energy development. Reducing the emission of soot and other pollutants from diesel locomotives is the focus and difficulty of air pollution control. Oxygenated synthetic fuel additives can not only be synthesized through the production of coal, biomass, synthesis gas or other industrial exhaust gas, but also significantly reduce the emission of soot and other pollutants. , Improve the application potential of thermal efficiency. Research results show that adding oxygen-containing fuel to diesel can effectively control the emission of pollutants in engine combustion exhaust. Common fuel additives mainly include methanol, ethanol, dimethyl ether, polymethoxy dimethyl ether and other oxygen-containing fuels. The development of oxygenated fuels such as M15 methanol gasoline and E10 ethanol gasoline is the most effective measure to significantly reduce diesel exhaust emissions.

Due to the limitations of mutual solubility, lubricity, boiling point, flash point, toxicity, swelling and corrosion, almost all gasoline additives cannot be used in diesel. Because gasoline additives such as methanol, ethanol, dimethyl carbonate, and MTBE cannot meet the performance requirements of diesel in terms of mutual solubility, flash point, boiling point, etc., even if the boiling point and flash point requirements are lowered, it is necessary to formulate stable methanol diesel or ethanol diesel without stratification. Adding a large amount of co-solvents and functional additives cannot pass the cost and safety barriers.

At present, only the production of biodiesel and tri- and tetra-polymethoxy dimethyl ether meet the requirements of diesel additives, but due to the limited amount of biodiesel resources and high production costs, the output cannot meet the requirements; the same is true for tri- and tetra-polymethoxy dimethyl ether Due to the high production cost, poor miscibility with diesel and poor water stability, it has affected its popularization and application. Coal-based diesel produced by the indirect method of coal originally has the performance advantages of low olefins and aromatics, low sulfur content and high cetane number. However, due to its low proportion, it does not meet the diesel standard and cannot be sold as a diesel product. Therefore, the development of oxygen-containing fuel additives that can be miscible with coal-based diesel and can significantly increase the specific gravity is of great significance for the development of indirect coal-to-liquid.

The applicant once invented the mixed oxalate series oxygenated fuel additives represented by mMEO, and established a new clean fuel system (authorized announcement number CN107118814B). However, it does not involve solving the miscibility of mixed oxalate and diesel. The characteristics and economical reasonable formula of mixed oxalate that can be miscible with diesel at room temperature have not been studied in depth.

Summary of the invention

In order to solve the above technical problems, the present invention provides a mixed oxalate used as a diesel fuel additive. In the mixed oxalate, the weight of dimethyl oxalate accounts for less than 20% of the total weight of the oxalate. , The percentage of the molar amount of the methyl substituent on the oxalate to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 60%.

In the present invention, the term "oxalate" refers to the oxalate formed by the esterification of oxalic acid and alkyl alcohol, and the oxalate has the following chemical formula (I):

Wherein, R ₁ and R _{2 are the} same or different, R _{1 is} selected from C ₁ -C ₂₂ alkyl, and R _{2 is} selected from C ₁ -C ₂₂ alkyl. Wherein R ₁ and R _{2 are} defined as alkyl substituents, if R ₁ and R ₂ are methyl, then R ₁ alkyl substituent is methyl substituent, R ₂ alkyl substituent is methyl substituent, corresponding The oxalate is dimethyl oxalate. If R ₁ and R ₂ are ethyl, the _{alkyl substituent of R 1} is ethyl substituent, and the _{alkyl substituent of R 2} is ethyl substituent. The corresponding oxalic acid The ester is diethyl oxalate. If R ₁ is a methyl group and R ₂ is an ethyl group, the _{alkyl substituent of R 1} is a methyl substituent, and the _{alkyl substituent of R 2 is} an ethyl substituent. The corresponding oxalic acid The ester is methyl ethyl oxalate. If a mixture contains dimethyl oxalate (abbreviated as DMO), diethyl oxalate (abbreviated as MEO), and methyl ethyl oxalate (abbreviated as DEO), the mixture is methyl ethyl oxalate mixed ester. By analogy, methyl butyl oxalate contains dimethyl oxalate, dibutyl oxalate (DBO), methyl butyl oxalate (MBO), and methyl ethyl propyl butyl oxalate contains dimethyl oxalate, diethyl oxalate, and oxalic acid. Dipropyl ester, dibutyl oxalate, methyl ethyl oxalate, methyl propyl oxalate, methyl butyl oxalate, ethyl propyl oxalate, ethyl butyl oxalate, propyl butyl oxalate. Mixed esters containing multiple oxalates are defined as mixed oxalates, so the above methyl ethyl oxalate (mMEO), methyl butyl oxalate (mMBO), and methyl ethyl propyl butyl oxalate (mMAO) are all mixed oxalates. One of the acid esters.

Preferably, in the above mixed oxalate, the weight of the dimethyl oxalate accounts for less than 11% of the total weight of the oxalate. Preferably, the weight of the dimethyl oxalate accounts for the total weight of the oxalate. The percentage of oxalate is less than 6%, and the molar amount of methyl substituents on the oxalate is less than 45% of the sum of all alkyl substituents on the oxalate. Preferably, the molar amount of the oxalate The molar amount of methyl substituents accounts for less than 41% of the sum of the molar amounts of all alkyl substituents on the oxalate.

Preferably, in the above mixed oxalate, the mixed oxalate is methyl ethyl oxalate mixed ester, and in the methyl ethyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 5% of the total weight of the oxalate, Preferably, the weight of dimethyl oxalate accounts for less than 1% of the total weight of oxalate, and the molar amount of methyl substituents on oxalate accounts for the molar amount of all alkyl substituents on oxalate. The percentage of the sum is less than 45%. Preferably, the molar amount of the methyl substituent on the oxalate is less than 23% of the sum of the molar amount of all the alkyl substituents on the oxalate; preferably, when When the diesel is No. 0 diesel, the weight of dimethyl oxalate accounts for less than 0.5% of the total weight of oxalate.

Preferably, in the above mixed oxalate, the mixed oxalate is methyl and ethyl oxalate with a boiling range of 176-178°C, referred to as mMEO (176-178), in which the content of dimethyl oxalate is less than or equal to 3%, Ethyl methyl oxalate and diethyl oxalate are the main ones, and the percentage of the molar amount of methyl substituents on the oxalate to the sum of the molar amounts of all alkyl substituents on the oxalate is less than 41%. Particularly preferably, the mixed oxalate is methyl ethyl oxalate mixed ester with a boiling range of 178-185°C, referred to as mMEO (178-185), in which the content of dimethyl oxalate is less than 0.5%, based on methyl ethyl oxalate and diethyl oxalate. Mainly, the percentage of the molar amount of the methyl substituent on the oxalate to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 25%, and the production cost of the mixed oxalate is the lowest.

Preferably, in the above-mentioned mixed oxalate, the mixed oxalate is methyl butyl oxalate mixed ester, and in the methyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 15% of the total weight of oxalate. The percentage of the molar amount of the methyl substituent on the ester to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 45%;

Preferably, in the above mixed oxalate, in the methyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 11% of the total weight of the oxalate ester, and the moles of the methyl substituents on the oxalate ester The percentage of the total amount of the molar amount of all alkyl substituents on the oxalate is less than 44%, and the weight content of methanol is less than 1% by weight;

Preferably, in the above-mentioned mixed oxalate, in the methyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 6% of the total weight of the oxalate ester, and the molar ratio of the methyl substituent on the oxalate ester The percentage of the total molar amount of all alkyl substituents on the oxalate is less than 40%, and the total content of methanol and butanol is less than 3wt%;

Preferably, in the above-mentioned mixed oxalate, the mixed oxalate is methyl ethyl propyl butyl oxalate mixed ester, and in the methyl ethyl propyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 5% of the total weight of the oxalate, The molar amount of the methyl substituents on the oxalate ester accounts for less than 20% of the sum of the molar amounts of all the alkyl substituents on the oxalate ester.

Preferably, in the above mixed oxalate, in the methyl ethyl propyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 3% of the total weight of the oxalate, and the molar ratio of the methyl substituents on the oxalate The percentage of the total molar amount of all alkyl substituents on the oxalate is less than 20%, and the total content of methanol, ethanol, propanol, and butanol is less than 2% by weight.

Preferably, in the above mixed oxalate, in the methyl ethyl propyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for less than 2% of the total weight of the oxalate, and the moles of the methyl substituents on the oxalate The percentage of the total amount of the total molar amount of all alkyl substituents on the oxalate is less than 15%, and the total content of methanol, ethanol, propanol, and butanol is less than 3% by weight.

The present invention also provides a clean diesel containing the above-mentioned mixed oxalate. The diesel contains the above-mentioned mixed oxalate, and the percentage of the mixed oxalate in the weight of the diesel is 5-90%. Preferably, in the above-mentioned clean diesel oil, the mixed oxalate is methyl and ethyl oxalate mixed ester, and the weight percentage of the methyl and ethyl oxalate mixed ester in the clean diesel oil is 5-30%.

Preferably, in the above-mentioned clean diesel oil, the weight percentage of dimethyl oxalate in the total weight of methyl ethyl oxalate is less than 0.5%, the diesel is No. 0 diesel, and the weight percentage of methyl and ethyl oxalate mixed in No. 0 diesel is 10%. The formulated diesel (referred to as ME10) meets the performance requirements of No. 0 diesel.

In the above-mentioned clean diesel oil, increasing the temperature of the diesel system can improve the miscibility of the methyl and ethyl oxalate mixed ester industrial product and diesel. The two are completely miscible at about 85°C. The alcohol content of the methyl and ethyl oxalate mixed ester is less than 5%. The methyl ester content is less than 25%, mainly methyl ethyl oxalate and diethyl oxalate, the molar weight of the methyl substituent on the oxalate is the percentage of the sum of the molar weight of all the alkyl substituents on the oxalate Less than 50%. Therefore, conditional diesel generators such as marine diesel engines can use methyl ethyl oxalate mixed ester by raising the temperature and keeping warm, so that the content of dimethyl oxalate in the methyl ethyl oxalate mixed ester can be higher and the cost is lower, and the methyl ethyl oxalate mixed ester It can be mixed with diesel fuel in any proportion of diesel engine fuel such as ships and vehicles. Preferably, when the diesel is heated, or when the flash point and specific gravity requirements are released, the addition ratio of the mixed oxalate in the diesel is any ratio.

According to the evaluation results of diesel bench experiments, the addition of mMEO in the range of 10% to 30% by weight has significant emission reduction effects, and the oil consumption is also low.

Preferably, in the above-mentioned clean diesel oil, the mixed oxalate is methyl butyl oxalate mixed ester, and the weight percentage of the methyl butyl oxalate mixed ester in the clean diesel oil is 5-40 wt%.

Preferably, in the above-mentioned clean diesel fuel, when the content of dimethyl oxalate in methyl butyl oxalate is not higher than 10%, the molar amount of methyl substituents on oxalate accounts for all the alkyl substituents on oxalate. The percentage of the sum of the molar amounts is less than 45%, and the addition amount of methyl butyl oxalate mixed in petroleum-based diesel can reach 15 wt%.

Preferably, in the above-mentioned clean diesel fuel, when the dimethyl oxalate content in the methyl butyl oxalate mixed ester is less than 0.5%, the molar amount of the methyl substituent on the oxalate accounts for the mole of all the alkyl substituents on the oxalate. The percentage of the total amount is less than 25%, and the methyl butyl oxalate mixed ester can be added to petroleum-based diesel at 40% by weight, which still meets the performance indicators of No. 0 diesel.

Preferably, in the above-mentioned clean diesel oil, the mixed oxalate is methyl ethyl propyl butyl oxalate mixed ester, and the weight percentage of the methyl ethyl propyl butyl oxalate mixed ester in the clean diesel oil is 5-30 wt%.

In the above-mentioned clean diesel oil, when the total content of mixed alcohol in the methyl ethyl propyl butyl oxalate mixed ester is less than 2% and the dimethyl oxalate is less than 1%, the methyl ethyl propyl butyl oxalate mixed ester is added to 30wt% in coal-based diesel or petroleum-based diesel, It can meet the performance requirements of No. 0 diesel.

Preferably, in the above-mentioned clean diesel, the above-mentioned clean diesel further contains a diesel co-solvent, the diesel co-solvent is selected from one or more of alcohols and glycerides, and the weight of the diesel co-solvent accounts for the weight of the clean diesel as a percentage 1-30%.

Preferably, the alcohol is selected from one or more of alcohols with C2 and C2 or higher. Preferably, the alcohols with C2 and C2 or higher are ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol or n-hexanol. Octanol.

Preferably, the glyceride is a glycerol fatty acid monoester (abbreviated as monoglyceride), glycerol fatty acid diester (abbreviated as glyceride), or glycerol and fatty acid mono- and double mixed esters (also known as glycerol and fatty acid mono- and double-ester mixtures).

In order to solve the problem of miscibility of mMEO with high methyl ratio in the weakly polar diesel system, we introduced a third component that can not only form strong hydrogen bonds with mMEO, but also promote dissolution in the weakly polar diesel component-low The mixture of carbon alcohol and glycerol fatty acid mono- and double-esters not only solves the problems of coal-based diesel system with low specific gravity, difficulty in adding oxygen-containing additives in large proportions to diesel system, and low cetane number of mMEO, but also innovates the clean production and production of bio-based diesel. The technical route for the application of by-product glycerin fuel, avoids the consumption of methanol.

According to the quality requirements for the flash point of No. 50 diesel oil, the flash point temperature must be ≥61℃ to meet the requirements of the national standard. Therefore, the alcohol content separately compounded in the mixed diesel must be ≤0.4wt%; C2 and above alcohols are used as the low boiling point group It can significantly reduce the flash point of the mixed system. The n-butanol in the fuel system that does not require flash point can be added in the same amount as mMEO, and the maximum addition amount of n-butanol can reach 20wt%.

Based on factors such as the source of raw materials, cost, etc., select commonly available alcohols such as methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-octanol, glycerol fatty acid monoester, etc. Among them, ethanol, n-propanol, and n-butanol can also be obtained through biomass fermentation, and glycerol fatty acid monoesters can be synthesized by transesterification of oil esters or waste oil with glycerol, which has a large amount of glycerin that is not yet well-used, and the raw materials can be continuously synthesized. With sufficient protection, there is also a large room for cost reduction.

Preferably, the glycerol and fatty acid mono- and double-mixed esters are mono- and double-ester mixtures that can be distilled after transesterification of oil esters and glycerol.

Adding alcohol or glyceride to the mixture of diesel and mixed oxalate can increase the miscibility of mixed oxalate and reduce the cloud point of diesel. For example, after adding methyl and ethyl oxalate mixed esters to diesel, then adding ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol or n-octanol, or adding glycerol fatty acid monoester or glycerol fatty acid diester, can be used for diesel oil The system solubilizes and lowers the cloud point.

Preferably, the alcohol is n-butanol, and the glyceride is glycerol and fatty acid mono- and double-mixed esters.

Preferably, adding glycerol and fatty acid single and double mixed esters with a content of about 90% has a significant effect on reducing the cloud point of diesel containing mixed oxalate and increasing cetane number. The added amount of glycerol and fatty acid single and double mixed esters is Less than 20wt% can meet the solubility requirements of No. 0 diesel.

Through the determination of mutual solubility and cloud point, we have found and confirmed that in the ternary system, n-butanol and glycerol fatty acid monoester are petroleum-based diesel-mMEO industrial product mixed systems are two types of better cosolvents, which can promote the mutual solubility of the system at room temperature. , Formulated new ternary systems such as diesel-mMEO-n-butanol, diesel-mMEO-glycerol fatty acid monoester and other new ternary systems that meet the performance requirements of No. 0 petroleum-based diesel.

Under the 20wt% mMEO-diesel system, observe the cloud point changes after adding various alcohols. Under the same mMEO addition amount, observe the organic alcohol that makes the cloud point of the system drop the fastest and the temperature drop the lowest. N-Butanol is the best co-solvent for the 20wt% mMEO-diesel mixed system.

Although n-butanol can play a stabilizing and solubilizing effect in a mixed system, the cetane number is only 17 and the flash point of the mixed fuel is about 20°C lower than that of diesel. The current market price is 6000 yuan/ton. , Diesel 5700 yuan/ton, the production cost of mMEO crude industrial products is within 2000 yuan/ton, the cost of new clean diesel produced with different ratios of three raw materials is about 5000 yuan/ton, which can reduce the cost of 500-1000 yuan/ton , Significant energy saving and emission reduction, therefore, the cost-effective advantage is obvious. When the flash point requirements are relaxed, it can be used as aviation fuel or marine fuel.

The present invention also provides the use of the above-mentioned mixed oxalate for improving the quality of diesel. The improvement of the quality of diesel is to reduce the cloud point of diesel, improve the mutual solubility of diesel, increase the flash point temperature of diesel, and reduce the swelling degree of diesel to non-polar materials. One or more of.

Preferably, when the diesel fuel can be heated, or when the flash point and specific gravity requirements are released, the addition ratio of the mixed oxalate ester in the diesel fuel is any ratio. The use of the mixed oxalate ester and diesel fuel is not affected by the diesel cloud point The limitation of diesel oil miscibility and diesel flash point temperature.

The present invention also provides the use of a composition comprising the above-mentioned mixed oxalate ester and the above-mentioned diesel co-solvent for improving the quality of diesel. One or more of the degree of swelling of diesel to non-polar materials.

Preferably, when the diesel fuel can be heated, or when the flash point and specific gravity requirements are released, the addition ratio of the mixed oxalate ester in the diesel fuel is any ratio. The use is not restricted by the cloud point of diesel, the mutual solubility of diesel, and the flash point temperature of diesel.

The above-mentioned mixed oxalate, diesel containing mixed oxalate, use of mixed oxalate, use of mixed oxalate and diesel co-solvent, etc., the diesel is petroleum-based diesel, coal-based diesel, biodiesel Of one or more of them.

Taking into account factors such as cost performance and abundant raw materials, we chose dimethyl oxalate as the basic raw material and ethanol, butanol and coal-to-liquid by-product mixed alcohol, oil ester and other large quantities of raw materials at a reasonable price. Three systems of methyl ethyl oxalate mixed ester, methyl butyl oxalate mixed ester and methyl ethyl propyl butyl oxalate mixed ester are used as additives for petroleum-based diesel and coal-based diesel.

The invention not only can produce mMEO and other series products at low cost in multiple ways, but also solves the problem that oxygenated diesel lacks suitable additives and cannot be added in large proportions. It successfully formulates a series of oxygenated mixed diesel that meets the performance requirements of No. 0 diesel and has stable performance. The problem of low specific gravity of coal-based diesel is solved.

The study found that the key factor affecting the freezing point of diesel oil in the mMEO composition is to control the content of dimethyl oxalate. The ratio of the three components can be adjusted by rectifying the pilot product mMEO. The miscibility in diesel oil and related performance indicators of diesel oil have optimized a reasonable formula.

The present invention provides a composition for improving the quality of diesel, which contains diesel co-solvent and mixed oxalate. When the diesel can be heated, or when the flash point and specific gravity requirements are released, the mixed oxalate is used in the diesel. The addition ratio of oxalate and diesel co-solvent is in any ratio, and the use of the composition of mixing oxalate ester and diesel co-solvent with diesel is not limited by the cloud point of diesel, the mutual solubility of diesel, and the flash point temperature of diesel.

The new clean diesel system of the present invention not only has the advantages of high cost performance, large-scale low-cost production and application, and significant emission reduction effect, but also has high boiling point and flash point and large specificity, can reduce the freezing point of diesel, and is safer and cleaner to use. This achievement can promote the clean and efficient utilization and coordinated development of petroleum-based, non-petroleum-based and biodiesel.

Therefore, the present invention also provides the use of the above-mentioned mixed oxalate, which is used as a component of non-petroleum-based diesel oil added in a large proportion, increasing the mutual solubility with diesel, increasing the specific gravity of coal-based diesel, and increasing the oxygen content of diesel. This makes diesel more suitable for use in oxygen-lean areas, and significantly reduces soot and pollutant emissions from diesel combustion.

The present invention also proposes that the industrial crude product of mixed methyl and ethyl oxalate is mainly used for compounding with third-party additives and diesel oil to develop a ternary system with lower flash point requirements, which can be used as aviation fuel or marine fuel. Based on factors such as the source of raw materials, cost, etc., commonly available alcohols such as methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, and n-octanol can be selected. Among them, ethanol, n-propanol, and n-butanol can also be obtained through biomass fermentation.

To study the mutual solubility of diesel-mMEO-cosolvent mixture system, firstly, petroleum-based diesel was used as the research object. Its simple and sensitive method is to measure the cloud point of the system. Refer to the national standard GB/T 6986-2014 "Petroleum products cloud point measurement method" By measuring the cloud point, the mutual solubility and low temperature stability of the mixed diesel can be evaluated. The specific method is as follows: Add methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-octanol in the mixture containing 10wt%, 20wt%, 30wt%, 40wt% mMEO and petroleum-based diesel. Quality, put the mixed sample into the low-temperature cooling liquid circulation tank, and cool the sample in a step-by-step cooling method. When the bottom of the sample tube appears crystallized or appears misty or turbid for the first time, the highest sample temperature is the cloud point of the sample , Expressed in °C. According to the results, the cloud point change curve is drawn, see Figure 9-15. It can be seen that the cloud point of the methanol mixed system does not decrease but rises. It may be that the carbon chain is too short. The remaining six organic alcohols have a significant decrease in the cloud point of the system, with n-butanol being the best.

In order to overcome the shortcomings of the new diesel-mMEO-n-butanol system, such as low flash point and low cetane number and limitation of n-butanol raw materials, biodiesel fatty acid methyl esters can be well miscible with diesel, but biodiesel Subject to cost and raw material constraints, it is difficult to become mainstream.

The existing biodiesel is synthesized by transesterification of animal, vegetable oil or waste oil with alcohol, but a large amount of by-product glycerol is difficult to use in the process. Although biodiesel has the advantages of high combustion heat, high cetane number, and green renewability, the biggest disadvantage is high production cost, the by-product glycerol is not well used, and there are problems such as waste water pollution. If the by-product glycerin from the production of biodiesel and fatty acids can be used instead of methanol and oil for direct transesterification to synthesize a mixed ester with glycerol fatty acid monoester as the main component and a small amount of diester, its polar glyceryl part can be used. Enhance the mutual solubility of mMEO in diesel oil, and the long carbon chain hydrocarbon group can increase the oil solubility of the mixed system and significantly increase the cetane number of the mixed system. Its molecular structure is as follows:

Wherein, R is a C ₁₂ -C ₂₃ alkyl group.

Preferably, in the above-mentioned fuel composition, the mixture of glycol monoester 89 minimizes the cloud point drop of the mMEO-diesel mixed system.

The beneficial effects of the present invention

The present invention has successfully developed a new diesel-mMEO-glycol monoester oxygenated mixed diesel system, which meets the cloud point requirements of diesel fuel, and not only makes up for the low cetane number of the diesel-mMEO-n-butanol system, but also solves the problem The problem of the outlet of glycerin by-products in the production of biodiesel and fatty acids, and avoids the use of methanol esterification process. This new system of ternary oxygenated diesel with good compatibility avoids new ways for the development and deployment of petroleum-based, non-petroleum-based, and biodiesel.

The above is the study of the ternary system product formula, all of which use the mMEO (ternary mixture of dimethyl oxalate, methyl ethyl oxalate and diethyl oxalate) proposed by the authorized announcement number CN107118814B as raw materials, and are used in petroleum-based diesel. Adding mMEO industrial products, according to meeting the cloud point requirements, adding n-butanol and glycol monoester to form a diesel-mMEO-n-butanol, diesel-mMEO-glycol monoester ternary system.

The results of testing related diesel indicators such as density, viscosity, cetane number index, flash point, cloud point, etc. of the petroleum-based diesel-mMEO-n-butanol system formula products studied in the previous stage show that the formula has a low flash point and the rest The indicators are in line with automotive standards, indicating that n-butanol is the main reason affecting the flash point of the hybrid system.

The present invention has developed ME10-petroleum-based diesel, MB15-petroleum-based diesel, MB20-coal-based diesel, MA20-petroleum-based diesel, MA30-coal-based diesel and other binary clean diesel fuels that meet the performance requirements of No. 0 diesel, and also developed oxalic acid The ternary clean diesel system of mMEO-n-butanol-diesel oil and mMEO-fatty acid monoglyceride-diesel oil has opened up a new way for the development of clean diesel with different labels and meet different needs.

Based on the previous research and development, we have found through more in-depth systematic research: mMEO is miscible with diesel at a temperature above 85℃, and alcohols above C2 are added to the mixed system of mMEO and diesel at room temperature. Alcohols above C2 are singly or mixed. The mixture transesterified with dimethyl oxalate can significantly improve the miscibility with petroleum-based and coal-based diesel, and the addition of long-chain mixed esters has a higher flash point and is safer. The content of the low-boiling alcohol component in the mixed ester seriously affects the flash point of the system, while the content of dimethyl oxalate affects the freezing point of the system. There is a correlation between the length ratio of the methyl group to the carbon chain hydrocarbon group and the solubility in the mixture. And regularity. Therefore, through the optimization of alcohol, control the molar ratio of the methyl group to other groups above C2 in the mixed ester and the content of free alcohol, dimethyl oxalate and other indicators, and make full use of ethanol, butanol and mixed alcohols that can be bio-fermented and chemically synthesized Such abundant resources can develop new binary and ternary coal-based and petroleum-based clean diesel systems with large additions and high cost performance.

Research on the quantification of the mutual solubility of carbon chain and diesel and mMBO and other extended systems, and develop new diesel additives and clean diesel systems that fully comply with diesel, especially the commonly used No. 0 diesel standards, are cost-effective, can be added in large proportions, and significantly save energy and reduce emissions. It is the key point and bright spot of the present invention.

Description of the drawings

Figure 1 is a diagram of the mutual solubility relationship between mMEO industrial crude product and petroleum-based diesel;

Figure 2 is a graph of the miscibility change of mMEO industrial crude product in coal-based diesel;

Figure 3 is a comparison chart of the miscibility changes of mMEO industrial crude products in petroleum-based diesel and coal-based diesel;

Figure 4 is a comparison chart of cloud point changes of mMEO (176-178) and mMEO (178-185) in petroleum-based diesel and coal-based diesel;

Figure 5 is a comparison diagram of cloud point changes of mMBO1, mMBO2, and mMBO3 in petroleum-based diesel;

Figure 6 is a comparison graph of cloud point changes of mMBO1, mMBO2, and mMBO3 in coal-based diesel.

Figure 7 is a hydrogen NMR spectrum of a: mMAO1, b: mMAO2;

Figure 8 is a graph showing the cloud point change of mMAO1 in coal-based diesel;

Figure 9 is a graph showing the change of cloud point of methanol to diesel-mMEO system;

Figure 10 is a graph showing the change of cloud point of ethanol to diesel-mMEO system;

Figure 11 is a graph showing the cloud point change of n-propanol to diesel-mMEO system;

Figure 12 is a graph showing the cloud point change of n-butanol to diesel-mMEO system;

Figure 13 is a graph showing the cloud point change of n-pentanol to diesel-mMEO system;

Figure 14 is a graph showing the cloud point change of n-hexanol to diesel-mMEO system;

Figure 15 is a graph of cloud point change of n-octanol on diesel-mMEO system;

Figure 16 is a graph showing the cloud point changes of 7 kinds of organic alcohols on the mixed system under the 20wt% mMEO-diesel system;

Figure 17 is a comparison diagram of the hydrogen nuclear magnetic spectrum of glycerin, soybean oil, and monoglyceride 68;

Figure 18 is an infrared spectrogram of soybean oil (a) and glycol monoester 68 (b);

Figure 19 is a graph showing the cloud point changes of Glycomonoester 68 in 9 diesel-mMEO mass percentage systems;

Figure 20 The hydrogen NMR spectrum of glycol monoester 89;

Figure 21 is a graph showing the cloud point change of glycerol 89 in the 20wt% mMEO-diesel system;

Figure 22 is a graph showing the cloud point of glycerol 68 and glycerol 89 in a 20% mMEO-diesel system;

Figure 23 is a graph showing the influence of the addition amount of n-butanol on the flash point of a petroleum-based hybrid diesel system.

Detailed ways

The technical scheme of the present invention will be further explained below in conjunction with specific embodiments. These examples are only used to illustrate the present invention and not to limit the scope of the present invention.

Example 1 Determination of cloud point of mMEO industrial crude product in petroleum-based diesel and coal-based diesel

The first is the laboratory synthesis method of mMEO industrial crude product. The specific method is as follows: According to the molar ratio of dimethyl oxalate, ethanol, and magnesium oxide catalyst of 1:2:0.025, use an analytical balance to accurately weigh 100g of DMO, 78g of ethanol, and 0.847g The light magnesia was placed in a round-bottom flask in turn, heated in an oil bath with a magnetic heating stirrer, and the temperature was set to 100°C. The reaction was refluxed for 6 hours. After the end, the heating temperature was set to 60°C, and the temperature was lowered. After reaching 60°C, a vacuum distillation reaction was started, and methanol and unreacted ethanol produced during the reaction were recovered, and then cooled to room temperature. The dimethyl oxalate and the catalyst were separated by filtration with 200-300 mesh silica gel powder to obtain a transparent and clear crude mMEO industrial product.

Then according to the mass percentage, use an analytical balance to accurately weigh the petroleum-based diesel and coal-based diesel into each sample bottle, and add 0wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt% to the corresponding ones respectively. , 60wt%, 70wt%, 80wt%, 90wt%, 100wt% mMEO crude industrial product-ready-to-use analytical balance to weigh 0.0g, 0.2g, 0.4g, 0.6g, 0.8g, 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2.0g of petroleum-based diesel and coal-based diesel were placed in 22 sample bottles, and then weighed 2.0g, 1.8g, 1.6g, 1.4g, 1.2g, 1.0g, 0.8g, 0.6g, 0.4g, 0.2g, 0.0g of crude mMEO industrial products were mixed in the corresponding sample bottles. According to the national standard GB/T 6986-2014 cloud point determination method of petroleum products, put the mixed sample into a low-temperature coolant circulation tank, and cool the sample in a step-by-step cooling method. When the bottom of the sample tube appears water mist or crystals for the first time, it appears foggy The highest sample temperature at the time of turbidity or turbidity is the turbidity point of the mixed fuel. See Figures 1, 2, and 3 for the results. Among them, Figure 1 is the mutual solubility diagram of mMEO industrial crude product and petroleum-based diesel, which shows that the two can be completely miscible at about 85℃; Figure 2 is the mutual solubility change diagram of mMEO industrial crude product in coal-based diesel, which shows that the two are at 95℃ The left and right sides can also be completely miscible; Figure 3 is a comparison chart of the miscibility changes of mMEO industrial crude product in petroleum-based diesel and coal-based diesel. It can be clearly seen that the mutual solubility of petroleum-based diesel and mMEO is better than coal-based diesel at any concentration. .

Example 2 Fractional distillation method of mMEO industrial crude product

Use German original fully automated real boiling point distillation instrument. The main accessories of this instrument are a 10L kettle, a matching packed tower (15 trays), and the instrument has a reflux ratio of 20:2 (20 is the number of refluxes, 2 is the number of collections), The condensing temperature is set at 50 sets and the cutting temperature is set at 163, 173, and 185 respectively, and atmospheric distillation is used in the rectification process. Take mMEO industrial crude product quantity as 2.2L, cut 163, 173, 185 boiling point distillation for 9 hours to obtain 169-173 segment 360g, 173-176 segment 479g, 176-178 segment 310g, 178-185 segment 350g. The obtained solutions are called mMEO (169-173), mMEO (173-176), mMEO (176-178), mMEO (178-185), and the front fraction contains a small amount of low-pressure and low-boiling residual liquid in the kettle with a total of 200g. The product analysis results are shown in the following Table 1-3. First, the mMEO (173-176), mMEO (176-178), and mMEO (178-185) gas chromatography are analyzed.

Table 1 mMEO (173-176) component content analysis

Based on the mass fractions of the above three components, it is calculated that the molar percentage of the methyl substituents of oxalate in mMEO (173-176) accounts for 57% of the alkyl substituents of all oxalates.

Table 2 mMEO (176-178) component content analysis results

According to the mass fractions of the above three components, it is calculated that the molar percentage of the methyl substituents of oxalate in mMEO (176-178) to the alkyl substituents of all oxalates is 40.3%.

Table 3 mMEO (178-185) component content analysis results

name

keep time

area

External standard content

Quality score

To	To	To	g/100ml	wt%
DMO	17.642	1060850	0.318	0.289
MEO	18.132	198688566	38.849	35.349
DEO	18.497	346284195	54.132	49.256

Based on the mass fractions of the above three components, it is calculated that the molar percentage of the methyl substituents of oxalate in mMEO (178-185) to the alkyl substituents of all oxalates is 22.4%.

Then analyze the proton nuclear magnetic spectrum of mMEO (176-178) and mMEO (178-185): the peak at about 4.3 ppm of chemical shift is the characteristic peak of hydrogen on the methylene groups at both ends of diethyl oxalate, about 3.8 ppm The peak at is the characteristic peak of methyl ethyl oxalate CH ₃ OCO- hydrogen, the peak at about 3.60 ppm is the characteristic peak of methyl ethyl oxalate hydrogen, the peak at about 1.30 ppm is methyl ethyl oxalate _{And the characteristic peak of methyl hydrogen on the CH 3} CH ₂ OCO- group in diethyl oxalate, the peak at about 1.15 ppm is the characteristic peak of hydrogen on ethanol methyl. At this time, the molar ratio of methyl to ethyl in mMEO (176-178) is 1:1.46, and the molar content of ethanol is 0.045. The molar ratio of methyl to ethyl in mMEO (178-185) is 1:3.33, and the molar content of ethanol is 0.125.

Example 3 Determination of cloud point of mMEO (176-178) and mMEO (178-185) in petroleum-based diesel and coal-based diesel

Add 0wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, 100wt% of mMEO(176-178), mMEO(178-185) to diesel oil respectively. )—The ready-to-use analytical balance weighs 0.0g, 0.2g, 0.4g, 0.6g, 0.8g, 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2g of petroleum-based diesel and coal-based diesel to 11 In each sample bottle, weigh the corresponding 2.0g, 1.8g, 1.6g, 1.4g, 1.2g, 1.0g, 0.8g, 0.6g, 0.4g, 0.2g, 0.0g mMEO ( 176-178), mMEO (178-185) are mixed in the sample bottle. According to the national standard GB/T6986-2014 petroleum product cloud point determination method, the sample bottle is placed in the low-temperature cooling liquid circulation tank, and the sample is cooled in stages. When wax crystals or water mist appear for the first time, they are foggy or turbid. The highest temperature at this time is the cloud point of the mixed fuel. See Figure 4 for the results.

It can be seen that to meet the cloud point requirements of the mixed fuel, mMEO (176-178) can be added up to 5wt% and mMEO (178-185) can be added up to 10wt% in petroleum-based diesel.

Example 4 Determination of density, freezing point, viscosity, and flash point of mMEO (176-178) and mMEO (178-185)

Take 8mL mMEO(176-178), mMEO(178-185) pure samples with density tube and measure each density in the automatic density meter; use condenser to take 5mL mMEO(176-178), mMEO(178-185) The pure sample is equipped with a thermometer and placed in a freezing point tester, and the freezing point value is determined according to the national standard method; use a viscosity tube to take 5ml mMEO (176-178), mMEO (178-185) pure samples and place them in the kinematic viscosity of petroleum products In the analyzer, each viscosity value is measured according to the national standard method; respectively take 60mL mMEO (176-178), mMEO (178-185) pure samples and place them in an automatic closed flash point meter, and measure each flash point value according to the national standard method.

The related diesel performance indicators of mMEO (176-178) and mMEO (178-185), including density, freezing point, viscosity, closed flash point and other performance parameters, are shown in Table 4.

Table 4 Measurement results of related performance parameters of No. 0 petroleum-based diesel and mMEO

Example 5 Determination of density, freezing point, viscosity, and flash point of mMEO (176-178) and mMEO (178-185) in petroleum-based diesel

Use the density tube to take 8mL 5wt%mMEO(178-185)-petroleum-based diesel, 10wt%mMEO(178-185)-petroleum-based diesel, and 5wt%mMEO(176-178)-petroleum-based diesel mixed samples in automatic density. Measure each density in a meter; use a condenser to take 5wt%mMEO(178-185)-petroleum-based diesel, 10wt%mMEO(178-185)-petroleum-based diesel, and 5wt%mMEO(176-178)-petroleum-based diesel. The sample is equipped with a thermometer and placed in a freezing point tester, and the determination is performed according to the national standard method to determine each freezing point value; use a viscosity tube to take 5wt%mMEO(178-185)-petroleum-based diesel, 10wt%mMEO(178-185)-petroleum Base diesel oil, 5wt% mMEO(176-178)-petroleum-based diesel oil mixed sample is placed in a petroleum product kinematic viscosity tester, and each viscosity value is measured according to the national standard method; respectively take 60mL5wt%mMEO(178-185)-petroleum-based diesel oil, The mixed samples of 10wt%mMEO(178-185)-petroleum-based diesel oil and 5wt%mMEO(176-178)-petroleum-based diesel oil were placed in an automatic closed flash point meter, and each flash point value was determined according to the national standard method.

5wt%mMEO(176-178)-petroleum-based diesel, 5wt%mMEO(178-185)-petroleum-based diesel, 10wt%mMEO(178-185)-petroleum-based diesel 3 product formulations and related diesel performance indicators include density, Performance parameters such as freezing point, viscosity and closed flash point are shown in Table 5.

Table 5 Measurement results of performance parameters of No. 0 petroleum-based diesel containing mMEO

10wt% mMEO(178-185)-petroleum-based diesel fuel mixture formula, see Table 6 for the full set of performance parameters according to the diesel national standard detection method.

Table 6 Test results of a full set of performance standards for 10wt% mMEO(178-185)-petroleum-based diesel formula

Example 6 Preparation of methyl butyl oxalate mixed ester mMBO

Dimethyl oxalate, n-butanol, and light magnesium oxide are accurately weighed according to the molar ratio of 1:1.6:0.025, respectively, corresponding to 12.9kg of dimethyl oxalate, 13.0kg of n-butanol, and 109g of light magnesium oxide in 3L frequency conversion In the speed-adjustable glass reactor, use a circulating oil bath to heat the reactor. Maintain the heating temperature of the oil bath at 110℃. The reaction will reflux for 6 hours. During the reaction, a large amount of liquid will reflux and continue atmospheric distillation to collect and produce Methanol and unreacted n-butanol. When the collected droplets slowly fall slowly, start to reduce the temperature in the oil bath to 60℃, wait for the temperature to drop to 60℃, and then start vacuum distillation2. After 4 or 6 hours, the generated methanol and unreacted n-butanol are recovered separately (the droplets fall very slowly at this time), and they are cooled to room temperature. Use a Buchner funnel (two layers of filter paper plus appropriate amount of silica gel powder) to filter and separate the precipitated dimethyl oxalate and catalyst. According to the time of vacuum distillation, three colorless and transparent methyl butyl oxalate mixed esters of different components are obtained, respectively, abbreviated as mMBO1, mMBO2, and mMBO3 total 18000g.

The product analysis results are as follows: First, analyze the three components of mMBO1, mMBO2, and mMBO3 by gas chromatography, see Table 7-9

Table 7 Gas chromatographic analysis results of mMBO1

According to the mass fractions of the above four components, it is calculated that the molar percentage of the methyl substituents of the oxalate in mMBO1 to the alkyl substituents of all the oxalates is 43.8%.

Table 8 Gas chromatographic analysis results of mMBO2

According to the mass fractions of the above four components, it is calculated that the molar percentage of the methyl substituents of the oxalate in mMBO2 to the alkyl substituents of all the oxalates is 36.6%.

Table 9 Gas chromatographic analysis results of mMBO3

According to the mass fractions of the above four components, it is calculated that the molar percentage of the methyl substituents of oxalate in mMBO3 to the alkyl substituents of all oxalates is 25.3%.

Then analyze the proton NMR spectrum of mMBO1, mMBO2, and mMBO3: the peak at about 4.20 ppm is the characteristic peak of hydrogen on the methylene groups at both ends of dibutyl oxalate, and the peak at about 3.85 ppm is dimethyl oxalate. The characteristic peak of hydrogen on the methyl group at both ends, the peak at about _{3.80ppm is the characteristic peak of methyl butyl oxalate CH 3} OCO-, the peak at 1.8-1.2ppm is the hydrogen on methyl butyl oxalate The peak at about 0.90 pm is the characteristic peak of the terminal methyl hydrogen on the _{CH 3} CH ₂ CH ₂ CH _{2 OCO- group in methyl butyl oxalate and dibutyl oxalate.} At this time, the molar ratio of methylbutyl in mMBO1 is 1:1.38; the molar ratio of methylbutyl in mMBO2 is 1:1.625; the molar ratio of methylbutyl in mMBO3 is 1:3.28.

Example 7 Determination of cloud point of mMBO1, mMBO2, mMBO3 in petroleum-based and coal-based diesel

Add 0wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, 100wt% of mMBO1, mMBO2, mMBO3 to petroleum-based and coal-based diesel respectively, namely Use an analytical balance to weigh 0.0g, 0.2g, 0.4g, 0.6g, 0.8g, 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2.0g of No. 0 petroleum-based diesel oil into 11 sample bottles , And then weigh the corresponding 2.0g, 1.8g, 1.6g, 1.4g, 1.2g, 1.0g, 0.8g, 0.6g, 0.4g, 0.2g, 0.0g mMBO1, mMBO2, and mMBO3 with an analytical balance. Mix well in the sample bottle. According to the national standard GB/T6986-2014 petroleum product cloud point determination method, the sample bottle is placed in the low-temperature cooling liquid circulation tank, and the sample is cooled in stages. When wax crystals or water mist appear for the first time, they are foggy or turbid. The highest temperature at this time is the cloud point of the mixed fuel. The comparison results of cloud point changes in petroleum-based diesel and coal-based diesel are shown in Figure 5-6.

The research methods and results of cloud point mutual solubility of mMBO1 and mMBO3 in petroleum-based diesel and coal-based diesel are shown in Table 10.

Table 10 Related performance test results of products and product formulations

The method is the same as before, and the specific results are shown in Figures 5 and 6. It can be seen that under the condition that the cloud point of the mixed fuel is satisfied, the petroleum-based diesel fuel can be added up to 15wt% mMBO1 and 20wt% mMBO3, and the coal-based diesel fuel can be added up to 20wt%-40wt% mMBO3.

mMBO1 and mMBO3 two products and 5wt%mMBO1-petroleum-based diesel, 10wt%mMBO1-petroleum-based diesel, 15wt%mMBO1-petroleum-based diesel, 5wt%mMBO3-petroleum-based diesel, 10wt%mMBO3-petroleum-based diesel, 15wt%mMBO3 -Petroleum-based diesel, 20wt% mMBO3-petroleum-based diesel, 20wt% mMBO3-coal-based diesel, 30wt% mMBO3-coal-based diesel, 40wt% mMBO3-coal-based diesel, 10 product formulations and related diesel performance indicators including density and freezing point , Viscosity, closed flash point and other performance parameters results are shown in Table 11-12.

Considering economy, add mMBO1 to petroleum-based diesel and mMBO3 to coal-based diesel. Petroleum-based diesel that meets the density requirements of No. 0 diesel can be added to 15wt% mMBO1, and coal-based diesel can be added to 40wt% mMBO3. 15wt% mMBO1-petroleum-based diesel, 20wt% mMBO3-coal-based diesel mixed formula full set of properties Refer to Table 11-12 for standard measurement results.

Table 11 Performance test results of 15wt% mMBO1-petroleum-based diesel formula

Table 12 Performance test results of 20wt% mMBO3-coal-based diesel formula

Example 8 Preparation of mMAO1 and mMAO2

Use an analytical balance to accurately weigh out 1000g of dimethyl oxalate, 402.7g of ethanol, 334.6g of propanol, 337.7g of butanol, and 16.9g of light magnesium oxide in a 3L reactor. Control the heating jacket temperature at 110～120℃ and the temperature of the reaction solution. The whole reaction was refluxed at 86-95°C for 2 hours, and the by-product methanol and unreacted ethanol were gradually distilled out at this temperature until the amount of distilled alcohol reached more than 650g. When the temperature is lowered to 60°C, the vacuum distillation starts, and the remaining low-boiling alcohol is extracted. As the distillate droplet speed decreases slowly, the temperature of the heating mantle is gradually increased. When the temperature reaches 100°C, the vacuum distillation ends for 40 minutes. Then, the entire reaction solution was cooled to 20° C., and the catalyst was filtered with 200-300 mesh silica gel powder to obtain 1280 g of methyl ethyl propyl butyl oxalate mixed ester mMAO1.

Use an analytical balance to accurately weigh out 1000g of dimethyl oxalate, 442.8g of ethanol, 312.3g of propanol, 288.9g of butanol, and 16.9g of light magnesium oxide in a 3L reactor. Control the heating jacket temperature at 110～120℃ and the temperature of the reaction solution. The whole reaction was refluxed at 86-95°C for 2 hours, and the by-product methanol and unreacted ethanol were gradually distilled out at this temperature until the amount of distilled alcohol reached more than 500g. When the temperature is lowered to 60°C, the vacuum distillation starts, and the remaining low-boiling alcohol is extracted. As the distillate droplet speed decreases slowly, the temperature of the heating mantle is gradually increased. When the temperature reaches 100°C, the vacuum distillation ends for 40 minutes. Then the whole reaction was cooled to 20°C, and the catalyst was filtered with 200-300 mesh silica gel powder to obtain 1260 g of mixed methyl ethyl propyl butyl oxalate mMAO2.

The above two kinds of mMAO1 and mMAO2 were analyzed by hydrogen NMR spectroscopy and gas chromatography. Refer to Figure 7 and Table 13-14 for product composition analysis data.

Table 13 mMAO1 component content analysis

Based on the mass fractions of the above fourteen components, it is calculated that the molar percentage of the methyl substituents of the oxalate in mMAO1 to all the alkyl substituents of the oxalate is 10%.

Table 14 mMAO2 component content analysis

According to the mass fractions of the above fourteen components, it is calculated that the molar percentage of the methyl substituents of the oxalate in mMAO2 to all the alkyl substituents of the oxalate is 18.6%.

Example 9 Determination of cloud point of mMAO1 in coal-based diesel

Weigh 0.0g, 0.2g, 0.4g, 0.6g, 1.0g, 2.0g of coal-based diesel with analytical balance into the corresponding test tube, and then use analytical balance to weigh the corresponding 2.0g, 1.8g, 1.6 g, 1.4g, 1.0g, and 0.0g of mMAO1 were mixed in the corresponding test tube and mixed with diesel fuel to form 0wt%, 10wt%, 20wt%, 30wt%, 50wt%, 100wt% mMAO1. With reference to the national standard GB/T 6986-2014 Cloud Point Determination of Petroleum Products, the sample bottle is placed in a low-temperature coolant circulation tank, and the sample is cooled in stages. When wax crystals or water mist appear for the first time, it appears misty or turbid. Record the highest temperature at this time, which is the cloud point of the mixed fuel. See Figure 8 for details.

The research method and results of the cloud point mutual solubility of the diluent mMAO1 in coal-based diesel are as follows: The method is the same as before, and the specific experimental results are shown in Figure 8. Under the condition that the cloud point of mixed fuel is met, 20wt% mMAO2 can be added to petroleum-based diesel; 20-30wt% mMAO1 can be added to coal-based diesel. 20wt% mMAO2-petroleum-based diesel, 20wt% mMAO1-coal-based diesel , 30wt% mMAO1-coal-based diesel fuel for the full set of performance standard measurement results of three products, see Table 15-17.

Table 15 Determination of a full set of performance standards for the 20wt% mMAO1-coal-based diesel formula

Table 16 Determination of a full set of performance standards for 30wt% mMAO1-coal-based diesel formula

Table 17 Determination of a full set of performance standards for 20wt% mMAO2-petroleum-based diesel formula

Example 10 Determination of cloud point of n-butanol in 20wt% mMEO-diesel system

Accurately weigh 0.4g of mMEO and 1.6g of petroleum-based diesel into 10 sample bottles, and then add 0.00g (blank control), 0.02g, 0.06g, 0.10g, 0.14g, 0.18g, 0.22 in sequence g, 0.26g, 0.30g, 0.34g of n-butanol in the sample bottle, shake and shake, observe the mutual solubility of the three solutions, refer to the national standard GB/T 6986-2014 petroleum product cloud point determination method, the mixed sample Put it into the low-temperature cooling liquid circulation tank, and cool the sample in a step-by-step cooling method. The highest sample temperature when water mist or crystals appear at the bottom of the sample tube and appears misty or turbid for the first time is the cloud point of the mixed fuel. See Figure 16 for the results.

Example 11 Preparation of glycerol fatty acid monoester by glycerol transesterification method

According to the quantity ratio of glycerin and soybean oil substance of 2.5:1, potassium hydroxide of 0.4% of soybean oil mass was added as a catalyst. Accurately weigh 8.8g of soybean oil, 2.30225g of glycerin, and 0.0352g of potassium hydroxide, add them to a 100ml three-necked flask with a stirring magnet, put the three-necked flask and three-way valve into a 200-burner (set in advance) Heat in an oil bath at a good temperature, and react for 3 hours.

After the reaction is over, first dip a pH paper into water, dip a glass rod into a small amount of oil to determine the pH value of the reactant. If it is under alkaline conditions, first add an appropriate amount of water to wash the layers, adjust with acid and wash with water to neutral, reduce pressure Dehydrate the product for later use. The product is subjected to hydrogen nuclear magnetic spectrometry and infrared spectroscopy to determine the content of monoglycerides in the product. The results of product analysis are shown in Figures 17, 18 and 20.

The method of preparing mixed esters based on glycerol and fatty acid monoesters is as follows: Weigh soybean oil, glycerin, potassium hydroxide and catalyst in sequence by mole, and add them to a 100ml flask with a stirring magnet, protected by nitrogen, and heated in an oil bath. React for several hours and control a certain temperature. After the reaction is over, add water to wash off the glycerin, filter and spin steam. The hydrogen nuclear magnetic spectrum and infrared spectroscopy of the product after the rotary steaming process are tested to obtain the successful synthesis of the glycerol monoester mixed product. The product was analyzed by liquid chromatography and found that the content of glycerol monoester was 68%, referred to as glycerol monoester 68 for short.

Preferably, in the above method, the molar ratio of glycerin, soybean oil, and potassium hydroxide is 2.5:1:0.025, the reaction is refluxed for 3 hours, and the temperature is controlled at 200°C.

The cloud point determination method of glycerol 68 to mMEO crude industrial product-diesel system is as follows:

In a mixture containing 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt% mMEO and petroleum-based diesel, the mass of glycerol 68 was sequentially increased, and each sample Put it into the low-temperature cooling liquid circulation tank, and cool the sample in a graded cooling method. The highest sample temperature when water mist or crystals appear at the bottom of the sample tube and becomes misty or turbid for the first time is the cloud point of the sample. ℃ said. Refer to Figure 19 for the specific cloud point change curve.

The glycerol monoester 68 was separated by silica gel chromatographic column. According to the external standard method, the separated glycerol monoester content was 89%, and the composition was determined by the hydrogen nuclear magnetic spectrum analysis, hereinafter referred to as glycerol monoester 89.

The present invention provides the cloud point determination of glycol monoester 89 in a 20 wt% mMEO-diesel system.

The specific method is as follows: in the mixture containing 20wt% mMEO crude industrial product-diesel oil, increase the mass of glycol monoester 89 in sequence, put each sample into the low-temperature coolant circulation tank, and cool the sample in a stepwise cooling manner. The highest sample temperature at which water mist or crystals appear at the bottom of the tube and becomes misty or turbid is the cloud point of the sample, expressed in °C. Refer to Figure 21 for the specific cloud point change curve.

The present invention also provides the cloud point temperature change of glycol monoester 68 and glycol monoester 89 in the 20wt% mMEO industrial crude product-diesel system. Refer to Figure 22 for the specific cloud point change curve.

Example 12 Liquid Chromatography Analysis of Glycerol Monoester

Standard sample preparation: Use 1ml centrifuge tube to prepare 4 gradients: 0.2mg/ml, 2mg/ml, 20mg/ml, 200mg/ml standards. First accurately weigh 200mg of pure glycerol monoester and 1ml centrifuge tube 1, use mobile phase B to fix the volume of centrifuge tube 1 to 1ml labeled as 200mg/ml; then use a pipette to take 100 microliters in centrifuge tube 1 In 1ml centrifuge tube 2, use mobile phase B to fix the volume of centrifuge tube 2 to 1ml, and mark as 20mg/ml; then use a pipette to take 100 microliters from centrifuge tube 2 into 1ml centrifuge tube 3, and use mobile phase B to determine The volume of the centrifuge tube 3 to 1ml is marked as 2mg/ml; use a pipette to take 100 microliters from the centrifuge tube 3 into the 1ml centrifuge tube 4, and use the mobile phase B to fix the volume of the centrifuge tube 4 to 1ml as 0.2mg/ml.

Sample preparation: accurately weigh 200mg of mixed glycerol monoester and 1ml centrifuge tube, use mobile phase B to fix the volume of the centrifuge tube to 1ml marked as 200mg/ml.

The mobile phase (A) uses 500ml of ultrapure water, and the mobile phase (B) uses a mixture of n-hexane and isopropanol (volume ratio 95:5), a total of 500ml. The chromatographic column is Agilent HC-C18-518905-902, the detection wavelength is set to 270nm, and the retention time is 4-5min. Record the peak area of each concentration at this time.

Example 13 Cloud Point Determination of Glycerol 68 in 9 mMEO-Diesel Mass Percentage Systems

In the mixture containing 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt% mMEO and petroleum-based diesel, add 0g (blank control), 0.02g, 0.06g, 0.10g, 0.14g, 0.18g, 0.22g, 0.26g, 0.30g, 0.34g of glycerol monoester 68 were mixed in the corresponding test tube. Refer to the national standard GB/T 6986-2014 "Petroleum Products Cloud Point Determination Method", put each sample into a low-temperature coolant circulation tank, and cool the sample in a stepwise cooling method. When the bottom of the sample tube appears water mist or crystallization for the first time The highest sample temperature when it appears foggy or turbid is the cloud point of the sample. See Figure 19 for the results.

Example 14 Determination of cloud point of monoglyceride 89 in 20wt% mMEO-diesel system

Accurately weigh 0.4g of mMEO and 1.6g of petroleum-based diesel in a test tube, a total of 10 samples, and then add 0g (blank control sample), 0.02g, 0.06g, 0.10g, 0.14g, 0.18g, 0.22g in sequence , 0.26g, 0.30g, 0.34g of glycerol monoester 89 in a test tube, shake well. Refer to the national standard GB/T 6986-2014 "Petroleum Products Cloud Point Determination Method" to measure the cloud point, put each sample into a low-temperature cooling liquid circulation tank, and cool the sample in a stepwise cooling method. When water appears at the bottom of the sample tube for the first time The highest temperature of the sample when it is misty or crystallized and appears misty or turbid is the cloud point of the sample. See Figure 21 for the results.

Example 15 Determination of the effect of n-butanol on the flash point of a mixed diesel system

Use an analytical balance to accurately weigh 54g of petroleum-based diesel oil into sample bottles labeled No. 1-7, then weigh 6g of mMEO (178-185) into sample bottles No. 2-7, and then weigh 0.1g in turn , 0.2g, 0.25g, 0.3g, 0.5g n-butanol in sample bottles 3-7, and bottles 1-2 are reference samples. The flash point of the samples in 6 sample bottles was measured with an automatic closed-mouth flash point meter. See Figure 23 for the results.

In order to further confirm and determine the influence of n-butanol on the flash point, and to make the product meet higher flash point requirements, the present invention provides to change the addition amount of n-butanol in the mMEO(178-185)-petroleum-based diesel system. Determine the flash point change of the mixed system. The specific method is as follows: Use an analytical balance to accurately weigh 54g of petroleum-based diesel oil into sample bottles labeled 1-7, and then weigh 6g of mMEO (178-185) into sample bottles 2-7, and then sequentially Weigh 0.1g, 0.2g, 0.25g, 0.3g, 0.5g of n-butanol into sample bottles 3-7, and bottles 1-2 as control samples. Measure the samples in 6 sample bottles with an automatic closed-mouth flash point meter, and obtain the flash point data in Table 18 below.

Table 18 Flash point data

Preferably, in the above method, when n-butanol is added to 0.2g, the flash point reaches 60.5. In accordance with the quality requirements for the flash point of No. 60 diesel oil, the flash point temperature must be ≥61℃ to meet the requirements of the national standard. Therefore, the content of alcohols such as n-butanol separately compounded in the mixed diesel must be ≤0.4wt%.

Example 16 Experimental determination of swelling

Purchase PP, PE, PVC corrosion-resistant materials and commonly used silicone, nitrile, fluorine, and fluorine rubber rings in the market, and conduct swelling tests on them. Firstly, weigh the above materials to be tested, and then soak them into 100wt% mMEO crude industrial product, 100wt% mMEO (178-185), 100wt% mMBO1, 100wt% mMBO3, 100wt% mMAO1, 100wt% mMAO2, petroleum-based Diesel, 10wt%mMEO(178-185)-petroleum-based diesel, 15wt%mMBO1-petroleum-based diesel, 20wt%mMBO3-coal-based diesel, 20wt%mMAO2-petroleum-based diesel, 20wt%mMAO1-coal-based diesel, 30wt%mMAO1 -Soak in coal-based diesel oil at room temperature for 24 hours, then take it out and wipe it clean with filter paper, and weigh the changes in the quality of the four rubber rings and the quality of PP, PE, and PVC. See Table 19 for the results.

The swelling test method of oxalate fuel and mixed fuel mixed with diesel on rubber and corrosion-resistant materials is as follows: Purchase PP (polypropylene), PE (polyethylene), PVC (polyvinyl chloride) corrosion-resistant materials in the market And commonly used silicone rubber (VMQ), nitrile (NBR), fluorine (VITON), fluorine rubber (FKM) rubber ring, to carry out the swelling test test. Firstly, weigh the above materials to be tested, and then soak them into 100wt% mMEO crude industrial product, 100wt% mMEO (178-185), 100wt% mMBO1, 100wt% mMBO3, 100wt% mMAO1, 100wt% mMAO2, petroleum-based Diesel, 10wt%mMEO(178-185)-petroleum-based diesel, 15wt%mMBO1-petroleum-based diesel, 20wt%mMBO3-coal-based diesel, 20wt%mMAO2-petroleum-based diesel, 20wt%mMAO1-coal-based diesel, 30wt%mMAO1 -Soak in coal-based diesel oil at room temperature for 24 hours, then take it out and wipe it clean with filter paper, and weigh the quality changes of the rubber ring, PP, PE, and PVC. The test results of the quality change of PP, PE, PVC materials, silicone, nitrile, fluorine, and fluorine rubber rings are shown in Table 19 below.

Table 19 Quality change test data of PP, PE, PVC, silica gel and other materials

It can be seen that the raw materials and mixed diesel have less swelling properties to PP, PE, and PVC materials, but have greater swelling properties to silica gel, nitrile, fluorine, and fluorine rubber.

Example 17 Application of Diesel Fuels with Different Ratios of mMAO to Marine Diesel Engine Bench Test D2 Cycle Mode

Mix different proportions of oxalate mMAO (using mMAO2, see Table 14 for specific ingredients) with diesel to form oxalate diesel for marine diesel engine benches. For marine auxiliary engines operating at a constant speed, the test mode is specified as D2 . The test results are shown in the table below.

Table 20 Engine bench test of pure diesel pure diesel

Table 21 Engine bench test of 10wt% mMAO diesel

Table 22 Engine bench test of 20wt% mMAO diesel

Table 23 Engine bench test of 30wt% mMAO diesel

The bench test results confirmed the feasibility of applying oxalate diesel to the bench of marine diesel engines. For D2 mode with a power ratio of 50% to 75%, NOx emissions are reduced, while CO emissions are increased. HC is lower than diesel at low power.

Example 18 Application of different proportions of mMAO diesel to marine diesel engine bench test E3 cycle mode

Different proportions of oxalate mMAO (using mMAO2, see Table 14 for specific ingredients) are mixed with diesel to form oxalate diesel for marine diesel engine benches. For marine auxiliary engines operating at variable speeds, the test mode is specified as E3. The test results are shown in the table below.

Table 24 Engine bench test of pure diesel

Table 25 Engine bench test of 10wt% mMAO diesel

Table 26 Engine bench test of 20wt% mMAO diesel

Table 27 Engine bench test of 30wt% mMAO diesel

The bench test results confirmed the feasibility of applying oxalate diesel to the bench of marine diesel engines. For E3 mode, at 50% power ratio, CO emissions are lower than diesel.

Example 19 Application of mMAO, mMBO, and mMEO diesel to vehicle diesel engine bench test

Add 10wt% of mMAO (using mMAO2, see Table 14 for specific components), mMBO (using mMBO1, see Table 7 for specific components), mMEO (using mMEO (178-185), see Table 3 for specific components) in diesel oil, Respectively used in the vehicle diesel engine bench test, the experimental results are shown in the following table.

Table 28 Engine bench experiment of mMAO, mMBO, mMEO/0# diesel

Experimental results show that three different types of oxalate can reduce PM emissions of diesel engines as a whole when adding 10wt% of oxalate to diesel, and reduce PM emissions at high power.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. Scope.

Claims (11)

1. A mixed oxalate used as a diesel fuel additive, characterized in that: in the mixed oxalate, the weight of dimethyl oxalate accounts for less than 20% of the total weight of the mixed oxalate. The percentage of the molar amount of the methyl substituents to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 60%.
2. The mixed oxalate according to claim 1, wherein the weight of the dimethyl oxalate accounts for less than 11% of the total weight of the mixed oxalate. Preferably, the weight of the dimethyl oxalate accounts for the total weight of the mixed oxalate. The percentage of the total weight of the oxalate is less than 6%, and the molar amount of the methyl substituent on the oxalate is less than 45% of the sum of the molar amount of all the alkyl substituents on the oxalate, preferably , The percentage of the molar amount of the methyl substituent on the oxalate to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 41%.
3. The mixed oxalate according to claim 1, wherein the mixed oxalate is methyl ethyl oxalate mixed ester, and in the methyl ethyl oxalate mixed ester, the weight of dimethyl oxalate accounts for the total weight of the methyl ethyl oxalate mixed ester The percentage of oxalate is less than 5%. Preferably, the weight of dimethyl oxalate accounts for less than 1% of the total weight of methyl ethyl oxalate, and the molar amount of methyl substituents on oxalate accounts for all of the oxalate esters. The percentage of the sum of the molar amount of alkyl substituents is less than 45%. Preferably, the percentage of the molar amount of the methyl substituents on the oxalate to the sum of the molar amounts of all the alkyl substituents on the oxalate is low. Preferably, when the diesel is No. 0 diesel, the weight of dimethyl oxalate accounts for less than 0.5% of the total weight of oxalate.
4. The mixed oxalate according to claim 1, wherein the mixed oxalate is methyl butyl oxalate mixed ester, and in the methyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for the total amount of methyl butyl oxalate mixed ester. The percentage by weight is less than 15%, and the percentage of the molar amount of the methyl substituent on the oxalate to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 45%.
5. The mixed oxalate according to claim 1, characterized in that: the mixed oxalate is methyl ethyl propyl butyl oxalate mixed ester, in the methyl ethyl propyl butyl oxalate mixed ester, the weight of dimethyl oxalate accounts for the total methyl ethyl propyl butyl oxalate mixed ester The percentage by weight is less than 5%, and the percentage of the molar amount of the methyl substituent on the oxalate to the sum of the molar amount of all the alkyl substituents on the oxalate is less than 20%.
6. A clean diesel containing mixed oxalate, characterized in that: the diesel contains the mixed oxalate of any one of claims 1-5, and the percentage of the mixed oxalate to the weight of the diesel is 5- 90%.
7. The clean diesel fuel of claim 6, wherein the mixed oxalate is methyl and ethyl oxalate mixed ester, and the weight percentage of the methyl and ethyl oxalate mixed in the clean diesel oil is 5-30%, or the mixed grass The ester is methyl butyl oxalate mixed ester, and methyl butyl oxalate accounts for 5-40 wt% of clean diesel oil. The weight percentage is 5-30wt%. Preferably, when the diesel is heated, or when the flash point and specific gravity requirements are released, the proportion of mixed oxalate in the diesel is any ratio. Preferably, the diesel is No. 0 Diesel, methyl ethyl oxalate mixed ester accounts for 10% by weight of No. 0 diesel.
8. The clean diesel fuel according to claim 6 or 7, characterized in that: the clean diesel fuel further contains a diesel co-solvent, the diesel co-solvent is selected from one or more of alcohols and glycerides, the diesel co-solvent The weight accounts for 1-30% of the weight of clean diesel.
9. The use of the mixed oxalate of any one of claims 1-5 to improve the quality of diesel, characterized in that: when the diesel can be heated, or when the flash point and specific gravity requirements are released, the mixed oxalate is The addition ratio in diesel is any ratio, and the use of mixed oxalate with diesel is not limited by the cloud point of diesel, the mutual solubility of diesel, and the flash point temperature of diesel.
10. A composition for improving the quality of diesel, which is characterized in that it contains a diesel co-solvent and the mixed oxalate according to any one of claims 1-5. When the diesel can be heated, or when the flash point and specific gravity are required to emit In the case of open, the addition ratio of mixed oxalate in diesel is any ratio, and the use of the combination of mixed oxalate and diesel co-solvent with diesel is not restricted by the cloud point of diesel, the mutual solubility of diesel, and the flash point temperature of diesel. .
11. The use of the mixed oxalate according to any one of claims 1 to 5, characterized in that the use is: as a component of non-petroleum-based diesel oil added in a large proportion, to increase the miscibility with diesel oil, and to improve coal-based diesel oil The specific gravity increases the oxygen content of diesel, making diesel more suitable for use in oxygen-lean areas, and significantly reducing the soot and pollutant emissions from diesel combustion.

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