阅读说明：本技术 一种对位硝基取代的α-二亚胺铁催化剂及其制备方法 (Para nitro substituted alpha-diimine iron catalyst and preparation method thereof ) 是由 黄志怀 于 2021-01-22 设计创作，主要内容包括：本发明提供一种对位硝基取代的α-二亚胺铁催化剂及其制备方法；该对位硝基取代的α-二亚胺铁催化剂的制备包括如下步骤：以无水甲醇为溶剂,甲酸为催化剂,2-苯基-4-硝基-6-异丙基苯胺与二酮发生取代反应,得到对位硝基取代的α-二亚胺配体；N-2保护下,对位硝基取代的α-二亚胺配体与FeCl-2进行配位得到α-二亚胺铁催化剂；在α-二亚胺铁催化剂的对位引入硝基,使α-二亚胺铁催化剂的电子云密度下降,有利于1-丁烯的配位插入,提高α-二亚胺铁催化剂的催化活性,催化1-丁烯聚合反应得到具有倾点低、粘度指数高的高级润滑油基础油。(The invention provides a para nitro substituted alpha-diimine iron catalyst and a preparation method thereof; the preparation method of the para nitro substituted alpha-diimine iron catalyst comprises the following steps: using anhydrous methanol as a solvent, formic acid as a catalyst, and carrying out substitution reaction on 2-phenyl-4-nitro-6-isopropyl aniline and diketone to obtain a para-nitro substituted alpha-diimine ligand; n is a radical of 2 Para nitro substituted alpha-diimine ligand and FeCl under protection 2 Carrying out coordination to obtain an alpha-diimine iron catalyst; introducing nitro group at para position of alpha-iron diimine catalystThe electron cloud density of the alpha-diimine iron catalyst is reduced, the coordination insertion of 1-butene is facilitated, the catalytic activity of the alpha-diimine iron catalyst is improved, and the 1-butene is catalyzed to perform polymerization reaction to obtain the high-grade lubricating oil base oil with low pour point and high viscosity index.)

1. A para-nitro substituted alpha-diimine iron catalyst, which is characterized in that: the structural formula of the alpha-diimine iron catalyst is as follows:

2. the method of claim 1 for preparing a para nitro substituted iron α -diimine catalyst, comprising: the method comprises the following steps:

s1: preparing a para-nitro-substituted alpha-diimine ligand;

adding 2-phenyl-4-nitro-6-isopropyl aniline and diketone into a dry flask, performing reflux reaction by using anhydrous methanol as a solvent and formic acid as a catalyst, filtering to obtain a precipitate after the reaction is finished, and passing the obtained crude product through CH₃OH/CH₂Cl₂Recrystallizing the mixed solvent, filtering, washing with cold ethanol, and drying in vacuum to obtain a para-nitro-substituted alpha-diimine ligand;

s2: preparing a para-nitro-substituted alpha-diimine iron catalyst;

in N₂Under protection, para-nitro-substituted alpha-diimine ligand and FeCl₂Mixing, adding CH₂Cl₂Stirring the mixture at room temperature for reaction, filtering the mixed solution, removing the solvent from the obtained liquid under rotary evaporation, washing the obtained solid with diethyl ether, and finally drying the solid in vacuum to obtain the catalyst.

3. The method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S1, the structural formula of the 2-phenyl-4-nitro-6-isopropylaniline is shown as follows:

4. the method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S1, the diketone has the following structural formula:

5. the method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S1, the amount of formic acid is 1-10% of the mass of 2-phenyl-4-nitro-6-isopropyl aniline.

6. The method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S1, the molar ratio of the 2-phenyl-4-nitro-6-isopropylaniline to the diketone is 2:1 to 2.5: 1.

7. The method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S1, the temperature of the reflux reaction is 25-60 ℃ and the time is 12-24 h.

8. The method of claim 2, wherein the iron catalyst is selected from the group consisting of iron (ll) para-nitro-substituted α -diimines: in step S2, the para-nitro-substituted alpha-diimine ligand and FeCl₂Mixing the raw materials in a molar ratio of 1: 1-1: 2; the stirring reaction time is 12-24 h.

9. A para-nitro substituted iron alpha-diimine catalyst in accordance with claim 1, wherein: the alpha-ferrous diimine catalyst is used for catalyzing 1-butene to perform oligomerization reaction, and the specific flow is as follows: adding alpha-ferrous diimine catalyst and 100ml of dried solvent into a 250ml polymerization bottle, stirring, degassing, adding 1-butene at reaction temperature, reacting under rapid stirring, and evaporating the solvent after the reaction is finished to obtain oily oligomer.

10. A para-nitro substituted iron alpha-diimine catalyst according to claim 9, wherein: in the polymerization reaction, the using amount of 1-butene is 10-50 g, the using amount of a catalyst is 1-10 mu mol, the reaction temperature is controlled at 0-60 ℃, the reaction time is 30-120 min, the reaction pressure is 1-10 atm, methylaluminoxane is adopted as a cocatalyst, and the molar ratio of the catalyst to the cocatalyst is 1: 100.

Technical Field

The invention belongs to the field of olefin catalytic polymerization, and particularly relates to a para-nitro-substituted alpha-diimine iron catalyst and a preparation method thereof.

Background

The poly-1-butene is a thermoplastic resin polymerized by 1-butene, is a semitransparent, colorless and odorless solid, has a regular molecular structure, and has chemical resistance, aging resistance and electrical insulation similar to those of polypropylene, but has unique performance, namely after being cooled and crystallized from a melt state, the thermoplastic resin can be changed into a relatively stable crystal form after being placed at room temperature for three or four days, and the strength and the rigidity are improved.

At present, the polymerization research of 1-butene is mainly focused on free radical polymerization, the free radical polymerization reaction speed is high, the molecular weight of a polymer is high, but the polymerization reaction is not controllable, and therefore, the invention provides the alpha-diimine iron catalyst which has higher catalytic activity and can catalyze the polymerization of 1-butene with controllable molecular weight.

Disclosure of Invention

In order to overcome the defects of the prior art, a para nitro substituted alpha-diimine iron catalyst and a preparation method thereof are provided, nitro is introduced into para of the alpha-diimine iron catalyst, so that the electron cloud density of the alpha-diimine iron catalyst is reduced, the coordination insertion of 1-butene is facilitated, the catalytic activity of the alpha-diimine iron catalyst is improved, and 1-butene is catalyzed to perform polymerization reaction to obtain high-grade lubricating oil base oil with low pour point and high viscosity index.

In order to achieve the above object, the present invention provides a para nitro substituted α -iron diimine catalyst, wherein the structural formula of the α -iron diimine catalyst is:

a preparation method of a para nitro substituted alpha-diimine iron catalyst comprises the following steps:

s1: preparing a para-nitro-substituted alpha-diimine ligand;

adding 2-phenyl-4-nitro-6-isopropyl aniline and diketone into a dry flask, performing reflux reaction by using anhydrous methanol as a solvent and formic acid as a catalyst, filtering to obtain a precipitate after the reaction is finished, and passing the obtained crude product through CH₃OH/CH₂Cl₂Recrystallizing the mixed solvent, filtering, washing with cold ethanol, and drying in vacuum to obtain a para-nitro-substituted alpha-diimine ligand;

s2: preparing a para-nitro-substituted alpha-diimine iron catalyst;

under the protection of N2, the para-nitro-substituted alpha-diimine ligand is reacted withFeCl₂Mixing, adding CH₂Cl₂Stirring the mixture at room temperature for reaction, filtering the mixed solution, removing the solvent from the obtained liquid by rotary evaporation, washing the obtained solid with diethyl ether, and finally drying the solid in vacuum to obtain the catalyst.

The reaction route of the specific synthesis steps of the reaction is as follows:

further, in step S1, the structural formula of the 2-phenyl-4-nitro-6-isopropylaniline is as follows:

further, in step S1, the diketone has the following structural formula:

further, in step S1, the amount of formic acid is 1% to 10% of the mass of 2-phenyl-4-nitro-6-isopropylaniline.

Further, in step S1, the molar ratio of the 2-phenyl-4-nitro-6-isopropylaniline to the diketone is 2:1 to 2.5: 1.

Further, in step S1, the temperature of the reflux reaction is 25 to 60 ℃ and the time is 12 to 24 hours.

Further, the para-nitro-substituted α -diimine ligand and FeCl in step S2₂Mixing the raw materials in a molar ratio of 1: 1-1: 2; the stirring reaction time is 12-24 h.

The FeCl₂The preparation method comprises the following steps: mixing ferric chloride and acetonitrile in a molar ratio of 1: 8-1: 50, refluxing for 5-10 h at 60-70 ℃, filtering, concentrating, and drying in vacuum to obtain powdery solid FeCl₂。

The alpha-ferrous diimine catalyst is used for catalyzing 1-butene to perform oligomerization reaction, and the specific flow is as follows: adding alpha-ferrous diimine catalyst and 100ml of dried solvent into a 250ml polymerization bottle, stirring, degassing, adding 1-butene at reaction temperature, reacting under rapid stirring, and evaporating the solvent after the reaction is finished to obtain oily oligomer.

Further, in the polymerization reaction, the amount of 1-butene is 10-50 g, the amount of a catalyst is 1-10 mu mol, the reaction temperature is controlled at 0-60 ℃, the reaction time is 30-120 min, the reaction pressure is 1-10 atm, methylaluminoxane is adopted as a cocatalyst, and the molar ratio of the catalyst to the cocatalyst is 1: 100.

Oily oligomer obtained by polymerization is used for preparing high-grade lubricant base oil.

According to the para-nitro substituted alpha-diimine iron catalyst provided by the invention, nitro is introduced into para positions of the alpha-diimine iron catalyst, so that the electron cloud density of the alpha-diimine iron catalyst is reduced, the coordination insertion of 1-butene is facilitated, the catalytic activity of the alpha-diimine iron catalyst is improved, and the 1-butene is catalyzed to perform polymerization reaction to obtain high-grade lubricating oil base oil with low pour point and high viscosity index.

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

1. the para-nitro substituted alpha-diimine iron catalyst introduces nitro groups at the para position of imine nitrogen atoms, and introduces nitro groups at the para position of the alpha-diimine iron catalyst, so that the electron cloud density of the alpha-diimine iron catalyst is reduced, the coordination insertion of 1-butene is facilitated, the catalytic activity of the alpha-diimine iron catalyst is improved, and the 1-butene is catalyzed to perform polymerization reaction to obtain high-grade lubricating oil base oil with low pour point and high viscosity index.

2. The catalyst is applied to butene polymerization reaction, can perfectly replace a free radical polymerization catalyst, reduces the process cost, has mild reaction conditions, does not need to be carried out under the harsh anhydrous and anaerobic conditions, and greatly reduces the process difficulty.

Drawings

FIG. 1 is a single crystal diffractogram of diimmonium ferric chloride.

Detailed Description

The invention will be further elucidated with reference to the following specific examples.

Example 1:

this example is to prepare a para-nitro substituted iron alpha-diimine catalyst, which is prepared by the following steps:

s1: synthesis of α -diimine ligand:

dissolving 2-phenyl-4-nitro-6-isopropylaniline (20mmol) and diketone (10mmol) in 30mL of anhydrous methanol, adding 0.25g of formic acid under stirring, carrying out reflux reaction at 45 ℃ for 40h, removing the solvent to obtain a crude product, and then adding CH₃OH/CH₂Cl₂(v/v ═ 15:1) mixed solvent was recrystallized, and a solid precipitate was precipitated, filtered and dried to obtain an α -diimine ligand in a yield of 78.2%.

The reaction formula is as follows:

s2: synthesis of alpha-iron diimine catalyst:

in N₂To a 100mL dry flask, the above alpha-diimine ligand (0.50mmol) was added and FeCl was added₂(5mmol) and 30mL CH₂Cl₂The reaction was stirred at room temperature for 24h, the suspension was filtered, the mixture was filtered, the resulting liquid was freed from the solvent in vacuo, the resulting solid was washed three times with diethyl ether (3X 30mL) and finally dried in vacuo to give a solid iron alpha-diimine catalyst in 86.4% yield.

The reaction formula is as follows:

example 2:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Adding 100mL of toluene solution under the atmosphere, introducing 10g of 1-butene, adding a dichloromethane solution (5mL) of the catalyst by using a syringe, carrying out polymerization reaction at 0 ℃ and 1atm for 30min, and adding 100mL of 3% hydrochloric acid/methanol solution to terminate the reactionThe polymer product is precipitated by shaking, the precipitate is filtered, washed thoroughly with anhydrous methanol and dried in vacuum at 50 ℃ for 12h to obtain the oligomer A.

Example 3:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 0 ℃ and 5atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12h, to obtain oligomer B.

Example 4:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 0 ℃ and 10atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12h, to obtain oligomer C.

Example 5:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 20 ℃ and 1atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours, to obtain oligomer D.

Example 6:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 20 ℃ and 5atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12h, to obtain oligomer E.

Example 7:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 20 ℃ and 10atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours, to obtain oligomer F.

Example 8:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10G of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 40 ℃ and 1atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours, to obtain oligomer G.

Example 9:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene,the specific process comprises the following steps: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 40 ℃ and 5atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12H, to obtain oligomer H.

Example 10:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 40 ℃ and 10atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12h, to obtain oligomer I.

Example 11:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 60 ℃ and 1atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12h to obtain oligomer J.

Example 12:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under an atmosphere, 100mL of toluene was addedAfter 10g of 1-butene and MAO (Al/Fe molar ratio: 100) were introduced into the solution, a methylene chloride solution (5mL) of the catalyst was added by a syringe, and polymerization was carried out at 60 ℃ and 5atm for 30min, 100mL of a 3% hydrochloric acid/methanol solution was added to terminate the reaction, and the polymer product was precipitated by shaking, and the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours to obtain an oligomer K.

Example 13:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 60 ℃ and 10atm for 30min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours, to obtain oligomer L.

Example 14:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, then a dichloromethane solution (5mL) of the catalyst was added by a syringe, polymerization was carried out at 60 ℃ and 1atm for 60min, then 100mL of 3% hydrochloric acid/methanol solution was added to terminate the reaction, the polymer product was precipitated by shaking, the precipitate was filtered, washed thoroughly with anhydrous methanol, and dried under vacuum at 50 ℃ for 12 hours, to obtain an oligomer M.

Example 15:

in this example, the catalyst obtained in example 1 was used to catalyze oligomerization of 1-butene, and the specific process was as follows: a250 mL polymerization flask with a magnetic stirrer was cyclically replaced with vacuum-nitrogen three times in N₂Under the atmosphere, 100mL of toluene solution was added, 10g of 1-butene and MAO (Al/Fe molar ratio 100) were introduced, and then a solution of the catalyst in methylene chloride (5mL) was added by syringe at 60 ℃ and 1atmAfter the polymerization reaction is carried out for 120min, 100mL of 3% hydrochloric acid/methanol solution is added to stop the reaction, the polymer product is precipitated by oscillation, the precipitate is filtered, the absolute methanol is used for fully washing, and the mixture is dried in vacuum at 50 ℃ for 12h to obtain the oligomer N.

In this example, the oligomers a to N obtained in examples 2 to 15 and the oligomer O obtained by radical polymerization were subjected to conventional hydrogenation saturation, and then physical and chemical property data were detected, and specific data are listed in table 1.

Table 1 oligomer physical and chemical properties table.

In this example, the molecular weight and molecular weight distribution of the polymer were measured at 150 ℃ using a PL-GPC220 high temperature gel permeation chromatography system; the kinematic viscosity of the polymer is determined according to the methods specified in GB265-88 and GB/T1995-88; the pour point of the polymer was determined according to the method specified in GB/T3535.

According to the table, the prepared alpha-diimine catalyst has higher activity in catalyzing polymerization of 1-butene, and has little difference compared with high-activity free radical polymerization; however, the obtained low polymers A to N have narrower molecular weight distribution compared with the low polymer O, and the low polymers A to N have lower pour points and higher viscosity indexes compared with the low polymer O, so that the high-grade lubricating oil base oil prepared from the low polymers A to N has lower pour points and higher viscosity indexes, and the high-grade lubricating oil prepared from the low polymers A to N improves the performance of the high-grade lubricating oil.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents and are included in the scope of the present invention.