CN110257115B

CN110257115B - A diesel pour point depressant and its preparation and application

Info

Publication number: CN110257115B
Application number: CN201910445722.0A
Authority: CN
Inventors: 薛原; 杨太顺; 解麦莹; 陈凤飞; 殷素雅; 韩生; 蔺华林; 李原婷; 黄燕山; 刘金宝; 周明安
Original assignee: Shanghai Institute of Technology
Current assignee: Shanghai Institute of Technology
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2021-05-28
Anticipated expiration: 2039-05-27
Also published as: CN110257115A

Abstract

The invention provides a diesel pour point depressant and its preparation and application. The preparation method of the diesel pour point depressant is characterized in that it includes step 1: mixing tetradecanol, a polymerization inhibitor and toluene, heating and stirring to make The solid is dissolved, methacrylic acid and a catalyst are added, the reaction temperature is raised, the product is washed with alkali and distilled water until neutral, and then rotary evaporated to obtain tetradecyl methacrylate; Step 2: add methacrylic acid to the reaction vessel tetradecyl ester, N-vinylimidazole and toluene were evacuated, passed through nitrogen, and then an initiator was added to carry out a polymerization reaction; the obtained reaction solution was rotary evaporated to remove the solvent, then added absolute ethanol to it for washing, and then vacuum-dried, Obtain diesel pour point depressant. The pour point depressant of the invention further enhances the pour point depressant effect of diesel oil, greatly improves the low temperature flow performance of diesel oil, and provides a broad space for the application of the pour point depressant in diesel oil.

Description

Diesel oil pour point depressant, and preparation and application thereof

Technical Field

The invention relates to a diesel pour point depressant, a preparation method and application thereof, and belongs to the technical field of pour point depressants.

Background

Diesel fuel is a complex mixture of multicomponent hydrocarbons including aliphatic, isoparaffins and aromatics as well as non-hydrocarbon compounds. At low temperature, when the length of a carbon chain is increased, the solubility of the diesel oil is reduced, the diesel oil begins to separate out in the form of wax crystals, and the wax crystals wrap the rest of liquid in a three-dimensional network structure to solidify and lose fluidity, so that the normal use and transportation of the diesel oil are affected. In particularly extreme weather, wax precipitation from diesel fuel affects the proper operation of the diesel engine. In order to solve the problem, a certain method is needed to improve the low-temperature flow property of the diesel oil, and the existing improvement methods comprise a blending method, a production process improvement method and pour point depressant addition.

The diesel oil pour point depressant can change the crystallization process of paraffin in diesel oil, so that the size of wax crystals is reduced and the wax crystals are uniformly dispersed, thereby effectively reducing the condensation point and the cold filter plugging point of the diesel oil and ensuring that the diesel oil normally flows under the low-temperature condition. When a small amount of pour point depressant is added into diesel oil, the crystallization temperature of crystals is effectively delayed, and the crystallization morphology of the crystals is changed, so that the wrapped liquid diesel oil flows out from the three-dimensional network structure. The flow property of the diesel oil is improved, and the application range and the application efficiency of the diesel oil are increased.

Currently, pour point depressants developed at home and abroad include alcoholysis/aminolysis of maleic anhydride, poly (meth) acrylates, ethylene-vinyl acetate esters, copolymerization pour point depressants, and the like.

Disclosure of Invention

The invention aims to provide a diesel pour point depressant, and preparation and application thereof, so as to improve the pour point depression effect.

In order to achieve the above object, the present invention provides a method for preparing a diesel pour point depressant, comprising:

step 1: mixing tetradecanol, a polymerization inhibitor and toluene, heating and stirring to dissolve solids, adding methacrylic acid and a catalyst, heating to a reaction temperature for reaction, washing a product with alkali and distilled water to be neutral, and performing rotary evaporation to obtain tetradecyl methacrylate;

step 2: adding tetradecyl methacrylate, N-vinyl imidazole and toluene into a reaction container, vacuumizing, introducing nitrogen, adding an initiator, and carrying out polymerization reaction; and carrying out rotary evaporation on the obtained reaction liquid to remove the solvent, adding absolute ethyl alcohol into the reaction liquid to wash the reaction liquid, and then carrying out vacuum drying to obtain the diesel pour point depressant.

The reaction equation of the diesel pour point depressant is as follows:

preferably, the polymerization inhibitor in step 1 is hydroquinone, and the dosage of the polymerization inhibitor is 0.55-0.65 percent of the total mass of the methacrylic acid and the tetradecanol, and the most preferable dosage is 0.6 percent.

Preferably, the catalyst in step 1 is p-toluenesulfonic acid in an amount of 1.1% to 1.3%, most preferably 1.2% of the total mass of methacrylic acid and tetradecanol.

Preferably, the reaction temperature in the step 1 is 90-130 ℃, and the reaction time is 4-6 h.

Preferably, the mol ratio of the tetradecyl methacrylate to the N-vinyl imidazole is 1: 1-6: 1.

Preferably, the initiator in the step 2 is benzoyl peroxide, and the dosage of the benzoyl peroxide is 0.8-1% of the total mass of the tetradecyl methacrylate and the N-vinyl imidazole.

Preferably, the polymerization temperature in the step 2 is 115-123 ℃; the polymerization time is 7-9 hours.

Preferably, the vacuum drying temperature in the steps 1 and 2 is 45-50 ℃; the drying time is 6-8 h.

The invention also provides an application method of the diesel pour point depressant, which is characterized by comprising the following steps: the diesel pour point depressant is added into the diesel according to 0.025-0.15 percent of the total mass of the diesel.

Aiming at the current research situation of the pour point depressant at present, the invention researches a diesel pour point depressant which has the advantages of simple synthesis method, few raw material types, stable performance, effective improvement of the pour point and the cold filter plugging point of the diesel pour point depressant through a small amount of dosage, good pour point depressing effect and the like. The polymer diesel oil pour point depressant of the invention can further improve the low-temperature fluidity of diesel oil, has simple synthesis method, less dosage and stable performance, and enhances the low-temperature fluidity of the diesel oil.

The long-chain alkyl of the diesel pour point depressant can increase the oil solubility of the polymer, so that the polymer is adsorbed on the surface of wax crystals to generate eutectic effect with the wax crystals. Vinyl imidazole has polar imidazole groups and can increase the solubility and dispersibility in diesel. The imidazole heterocycle containing N atoms changes the crystal habit of wax in the diesel oil, prevents wax crystals from contacting with each other and combining into a large block, and adopts a solution polymerization method to synthesize the polymer pour point depressant in order to realize better effect.

Compared with the prior art, the invention has the beneficial effects that:

(1) in the pour point depressant prepared by the method, long-chain ester alkane is eutectic with paraffin crystals in diesel oil, so that the oil solubility of the polymer is increased.

(2) In the pour point depressant prepared by the invention, the vinylimidazole has polar imidazole groups, and the vinylimidazole has polar imidazole groups, so that the solubility and the dispersibility in diesel oil can be improved. The imidazole heterocycle containing N atoms changes the crystal habit of wax in the diesel oil and prevents wax crystals from contacting with each other and combining into a large block.

(3) The pour point depressant prepared by the invention has the advantages of simple synthesis method, few raw material types, small dosage and stable performance.

(4) The pour point depressant further enhances the pour point depression effect of diesel oil, greatly improves the low-temperature flow property of the diesel oil, and provides wide space for the application of the pour point depressant in the aspect of the diesel oil. The obtained diesel pour point depressant is added into the commercial 0# diesel, the condensation point of the diesel can be respectively reduced by 22-24 ℃ and 6-7 ℃ to the maximum, and the diesel has better fluidity at low temperature.

Drawings

FIG. 1 is a 1HNMR picture of a tetradecyl methacrylate-N-vinylimidazole polymer; (m and n are integers of 1 or more)

FIG. 2 shows an infrared diagram of a tetradecyl methacrylate-N-vinylimidazole polymer.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims. The raw materials used in the following examples are commercially available from Shanghai Tantake technologies, Inc.

Example 1

A diesel oil pour point depressant is a copolymer polymerized by tetradecyl methacrylate and N-vinyl imidazole, and the preparation method comprises the following steps:

(1) putting a three-neck flask into a constant-temperature magnetic stirrer provided with a thermometer, a reflux condenser tube and a water separator, adding 10.37g (0.048mol) of tetradecanol, 0.0922g of hydroquinone serving as a polymerization inhibitor and 30ml of toluene, mixing, heating to 60 ℃, stirring to completely dissolve solids, quickly adding 4.998g (0.058mol) of methacrylic acid and 0.1844g of p-toluenesulfonic acid, heating to 90 ℃, reacting for 1 hour, and continuously heating to 125 ℃, and carrying out reflux reaction for 5 hours. After the reaction is finished, cooling to room temperature, pouring the reaction product into a separating funnel, washing the reaction product for 3 times by using 5% NaOH until the reaction product is alkalescent, washing the reaction product for 3 times by using distilled water until the reaction product is neutral, standing and layering the reaction product to remove bottom liquid, pouring the upper layer substance into a round-bottom flask, performing rotary evaporation by using a rotary evaporator at 50 ℃, and drying the upper layer substance in a vacuum drying oven at 50 ℃ for 6 hours to obtain the tetradecyl methacrylate.

(2) 9.0037g (0.03mol) of tetradecyl methacrylate, 1g (0.01mol) of N-vinylimidazole and 30ml of toluene are sequentially added into a three-neck flask in a constant-temperature magnetic stirrer provided with a constant-pressure separating funnel, a reflux condenser tube and a nitrogen inlet tube, the three-neck flask is vacuumized for 1-3min, nitrogen is introduced for 1-3min, and the process is repeated three times to remove air in the reaction flask. When the temperature reaches 115 ℃, 20mL of toluene solution dissolved with 0.0900g of benzoyl peroxide is slowly dropped (dropping is finished in 30-45 min), and the polymerization reaction is carried out for 8h under stirring and refluxing at 115 ℃. And (3) after the reaction is finished, cooling to room temperature, carrying out rotary evaporation on the obtained reaction liquid at 50 ℃ to remove the solvent until no liquid flows out, pouring absolute ethyl alcohol to wash for 3-4 times to remove the initiator benzoyl peroxide to obtain a sticky jelly, and putting the sticky jelly into a vacuum drying oven at 50 ℃ to carry out vacuum drying for 8 hours to obtain the tetradecyl methacrylate-N-vinylimidazole polymer pour point depressant shown in the formula (I). The polymer had a molecular Mw of 76000g/mol, Mn of 54000g/mol, and Mw/Mn of 1.407 by GPC. The obtained product was characterized by nuclear magnetism as shown in FIG. 1 and by infrared as shown in FIG. 2.

Example 2

A diesel oil pour point depressant is a copolymer formed by polymerizing tetradecyl methacrylate and N-vinyl imidazole, and is shown in a formula (I). The polymer was tested by GPC to have a molecular Mw of 75800g/mol, an Mn of 57060g/mol, and an Mw/Mn of 1.328. The preparation process differs from example 1 in that 6.0024g (0.02mol) of tetradecyl methacrylate and 2g (0.02mol) of N-vinylimidazole are added in step (2).

Example 3

A diesel oil pour point depressant is a copolymer formed by polymerizing tetradecyl methacrylate and N-vinyl imidazole, and is shown in a formula (I). The polymer had a molecular Mw of 77060g/mol, Mn of 59600g/mol and Mw/Mn of 1.293 by GPC. The preparation process differs from example 1 in that in step (2) 18.007g (0.06mol) of tetradecyl methacrylate and 1g (0.01mol) of N-vinylimidazole are added.

Application examples

The diesel pour point depressants prepared in the above examples 1 to 3 are respectively numbered as 1, 2 and 3, and are respectively added into the No. 0 diesel of Songjiang according to 0.025 percent to 0.015 percent of the diesel. The freezing point was determined according to GB/T510-1991 and the cold filter point was determined according to SH/T0248-2006. The results of the duplicate determinations were averaged. The results of the 0# diesel pour point and cold filter plugging point tests with the addition of the diesel pour point depressants obtained in examples 1-4 are shown.

Δ SP represents the reduction in the pour point of 0# diesel fuel after addition of the diesel fuel pour point depressant of the present invention relative to 0# diesel fuel. The delta CFPP represents the cold filter plugging point reduction value of 0# diesel fuel relative to 0# diesel fuel with the diesel fuel pour point depressant of the invention added. From the test results of examples 1-3, the pour point depressant of the invention has obvious effect on reducing the condensation point and the cold filter plugging point of diesel oil, the highest condensation point is reduced by 24 ℃, and the cold filter plugging point is reduced by 7 ℃.

The above description is only a basic description of the present invention, and any equivalent changes made according to the technical solution of the present invention belong to the protection scope of the present invention.

Claims

1. a preparation method of diesel pour point depressant, is characterized in that, comprises:

Step 1: Mix tetradecanol, polymerization inhibitor and toluene, heat and stir to dissolve the solid, add methacrylic acid and a catalyst, raise the reaction temperature to react, the product is washed with alkali and distilled water until neutral, and then rotary evaporated to obtain Myristyl methacrylate; the polymerization inhibitor is hydroquinone, and its consumption is 0.55%-0.65% of the total mass of methacrylic acid and tetradecanol; the catalyst is p-toluenesulfonic acid, and its consumption is methyl benzene 1.1%-1.3% of the total mass of acrylic acid and tetradecanol;

Step 2: Add tetradecyl methacrylate, N-vinylimidazole and toluene into the reaction vessel, evacuate, pass nitrogen, and then add an initiator to carry out a polymerization reaction; remove the solvent by rotary evaporation of the obtained reaction solution, and then add it to the reaction vessel. Wherein, add dehydrated alcohol for washing, then vacuum dry to obtain diesel pour point depressant; the molar ratio of described tetradecyl methacrylate and N-vinylimidazole is 1:1～6:1; The amount of benzoyl oxide is 0.8%-1% of the total mass of tetradecyl methacrylate and N-vinylimidazole.

2. The preparation method of diesel pour point depressant according to claim 1, wherein the reaction temperature in the step 1 is 90-130°C, and the reaction time is 4-6h.

3. The preparation method of diesel pour point depressant according to claim 1, wherein the polymerization temperature in the step 2 is 115-123°C; the polymerization reaction time is 7-9 hours.

4 . The preparation method of diesel pour point depressant according to claim 1 , wherein the vacuum drying temperature in the step 2 is 45-50° C.; the drying time is 6-8 h. 5 .