CN116023533A - Neodymium phosphonate solution and preparation method and application thereof - Google Patents

Abstract

The invention relates to the field of preparation of neodymium phosphonate, and discloses a neodymium phosphonate solution, a preparation method and application thereof. The neodymium phosphonate solution is characterized in that the solution viscosity of the neodymium phosphonate solution is lower than 200 mPa.s when measured at the concentration of 0.1mol/L at 25 ℃, and the chloride ion content in the neodymium phosphonate solution is not higher than 10ug/g when the concentration of the neodymium phosphonate is 0.1 mol/L. The neodymium phosphonate solution has the advantages of low viscosity and low impurity content, can be conveniently applied to industrial production, and is particularly favorable for conveying and accurate metering.

Description

Phosphonate neodymium solution and its preparation method and application

technical field

The invention relates to the field of neodymium phosphonate preparation, in particular to a neodymium phosphonate solution and its preparation method and application.

Background technique

Phosphonate was used as an extractant to extract metal elements in rare earths, and then it was accidentally discovered that neodymium phosphonate had activity in catalyzing the polymerization of conjugated dienes, which attracted people's attention. Both the Changchun Institute of Applied Chemistry and Michelin of China Sciences have carried out research on conjugated dienes based on neodymium phosphonate catalysts, and can obtain products with high cis-1,4-structure content (>97%), and found that neodymium phosphonate It can be catalytically active at a very low amount of alkylating agent ([Al]/[Nd]=5), while other neodymium salt systems have no catalytic activity at such a low amount of aluminum. This feature makes the cost of the catalyst relatively low, creating favorable conditions for industrial applications.

Currently, neodymium phosphonates are prepared in two ways. The one, solid method, as CN1479753A record this method gained solid type neodymium phosphonate can not dissolve completely in industrial common solvent (alkane, toluene etc.), the catalyst of gained is viscous suspension liquid state, this heterogeneous catalyst one On the one hand, it will lead to low utilization efficiency of neodymium atoms, on the other hand, it may cause difficulties in transportation and inaccurate measurement, which will bring difficulties to industrial production. The second is the solution method, but due to the characteristics of neodymium phosphonate, the viscosity of the solution is relatively high, usually above 10000mPa·s. This makes it difficult to separate the oil phase and the water phase during the synthesis process, and it is difficult to remove the water in the oil phase, resulting in a large amount of impurities in the neodymium phosphonate, which further affects subsequent use. In addition, the high viscosity also makes the fluidity of neodymium phosphonate particularly poor, and it is jelly-like, which makes it difficult to measure accurately during application and cannot be used in industrial production.

In order to solve the problem of high viscosity, CN103694378A added a viscosity modifier in the neodymium phosphonate solution after the synthesis reaction, such as di(2-ethylhexyl)phosphonate ester, 2-ethylhexylphosphonate-2 -Ethylhexyl ester, methyl phosphonate dimethyl heptyl ester, phosphonate tributyl ester, phosphonate triphenyl ester, phosphonite dioctyl ester, phosphonite diethyl ester, phosphonite One or more of ester diphenyl ester, dimethyl phthalate, diethyl phthalate, dioctyl phthalate, the amount of viscosity modifier added is the same as that of neodymium in organic phosphonate neodymium The molar ratio is 0.25～3:1. The addition of a viscosity modifier can significantly reduce the viscosity of the final product, but it cannot solve the problem of high impurity content caused by layering difficulties in the synthesis process.

CN103224517A adds butadiene and/or isoprene and alcohols to the oil phase, such as ethanol, propanol, butanol, hexanol, etc., although the viscosity of the solution is improved, the alcohols introduced are not suitable for subsequent use. It is also an impurity for rare earth catalysts.

Contents of the invention

The object of the present invention is to provide a neodymium phosphonate solution and its preparation method and application. The neodymium phosphonate solution of the present invention has the advantages of low viscosity and low impurity content.

The first aspect of the present invention provides a neodymium phosphonate solution, wherein the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25°C is lower than 200 mPa·s, and the phosphonate neodymium solution is The chloride ion content in the neodymium phosphonate solution is not higher than 10ug/g when the neodymium phosphonate concentration is 0.1mol/L.

Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25° C. is lower than 100 mPa·s.

Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7 ug/g when the concentration of neodymium phosphonate is 0.1 mol/L.

Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5 mol/L, preferably 0.1-0.2 mol/L.

Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

According to the second aspect of the present invention, there is provided a method for preparing the above-mentioned neodymium phosphonate solution, wherein the method comprises: a step of contacting an aqueous solution of neodymium chloride, an organic phosphonate, an organic solvent and an alkaline compound, wherein the The molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4-6:1, and the amount of the basic compound is such that the pH value of the aqueous phase is less than or equal to 5.

Preferably, the contacting includes: first contacting the aqueous solution of neodymium chloride with an organic phosphonate and an organic solvent, and then making a second contact with the product of the first contact with a basic compound.

Preferably, the neodymium chloride content in the neodymium chloride aqueous solution is 0.1-0.5 mol/L.

Preferably, the molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4-5:1.

Preferably, the organic phosphonate has a structure represented by formula (1), wherein R ^d1 , R ^d2 and R ^d3 are each independently hydrogen, hydroxyl, C ₁ -C ₂₀ alkyl or C ₁ -C ₂₀ , and at least one of R ^d1 , R ^d2 and R ^d3 is C ₁ -C ₂₀ alkyl or C ₁ -C ₂₀ alkoxy,

Preferably, in formula (1), R ^d1 is hydroxyl, and both R ^d2 and R ^d3 are 2-ethylhexyloxy.

Preferably, in formula (1), R ^d1 is hydroxyl, and both R ^d2 and R ^d3 are 2-ethylhexyl.

Preferably, in formula (1), R ^d1 is hydroxyl, R ^d2 is 2-ethylhexyl, and R ^d3 is 2-ethylhexyloxy.

Preferably, the organic solvent is one or more of C ₅ -C ₁₀ alkanes, C ₅ -C ₁₀ cycloalkanes and C ₆ -C ₁₂ aromatics; more preferably, the organic solvent is hexane, One or more of cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene.

Preferably, the amount of the organic solvent is such that the volume of the organic phase and the volume of the aqueous phase are 0.3˜2:1.

Preferably, the basic compound is used in an amount such that the pH of the aqueous phase is 4-5.

Preferably, the basic compound is used in the form of an aqueous solution, and the content of the basic compound in the aqueous solution of the basic compound is 0.1-5.0 mol/L; more preferably, the aqueous solution of the basic compound is added dropwise to the first contact product The second contacting is carried out; more preferably, the dropping rate is 2.0-20.0 mL/min.

Preferably, the basic compound is one or more of hydroxide and ammonia water.

Preferably, the second contact temperature is 30-80°C.

According to the third aspect of the present invention, the neodymium phosphonate solution prepared by the preparation method of the present invention is provided.

Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25°C is lower than 200 mPa·s, and the chloride ion content in the neodymium phosphonate solution is lower than that of the neodymium phosphonate solution. When the concentration is 0.1mol/L, it should not be higher than 10ug/g.

Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25° C. is lower than 100 mPa·s.

Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7 ug/g when the concentration of neodymium phosphonate is 0.1 mol/L.

Preferably, the concentration of the neodymium phosphonate solution is 0.04-0.5 mol/L, preferably 0.1-0.2 mol/L.

Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

According to the fourth aspect of the present invention, the application of the neodymium phosphonate solution of the present invention or the neodymium phosphonate solution prepared by the preparation method of the neodymium phosphonate solution of the present invention in the preparation of olefin polymerization catalysts is provided.

The neodymium phosphonate solution according to the present invention has the advantages of low viscosity and low impurity content, can be conveniently applied in industrial production, and is particularly beneficial to transportation and precise metering.

Detailed ways

Neither the endpoints nor any values of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

In the first aspect of the present invention, a neodymium phosphonate solution is provided. The viscosity of the neodymium phosphonate solution measured at a concentration of 0.1mol/L at 25°C is lower than 200mPa·s, and the neodymium phosphonate solution is The chloride ion content in the neodymium solution is not higher than 10ug/g when the concentration of neodymium phosphonate is 0.1mol/L.

According to the present invention, preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25°C is lower than 100mPa·s; more preferably, the neodymium phosphonate solution is at 25°C The viscosity of the solution measured at a concentration of 0.1mol/L is lower than 90mPa·s; more preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1mol/L at 25°C is 40-90mPa ·s.

Specific values of the solution viscosity measured as the neodymium phosphonate solution at a concentration of 0.1mol/L at 25°C include, for example: 5mPa·s, 10mPa·s, 20mPa·s, 30mPa·s, 40mPa·s s, 42mPa·s, 50mPa·s, 60mPa·s, 65mPa·s, 70mPa·s, 80mPa·s, 87mPa·s, 90mPa·s, 100mPa·s, 112mPa·s, 130mPa·s, 150mPa·s, 173mPa·s or 190mPa·s.

According to the present invention, preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 10ug/g when the neodymium phosphonate concentration is 0.1mol/L; When the concentration of neodymium is 0.1mol/L, it is not higher than 9ug/g; more preferably; the chloride ion content is not higher than 8ug/g when the concentration of neodymium phosphonate is 0.1mol/L; more preferably; the chlorine The ion content is not higher than 7ug/g when the neodymium phosphonate concentration is 0.1mol/L; more preferably, the chloride ion content is 5-7ug/g when the neodymium phosphonate concentration is 0.1mol/L.

As the specific value of the chloride ion content, for example, 1ug/g, 2ug/g, 3ug/g, 4ug/g, 5ug/g, 6ug/g, 7ug/g, 8ug/g, 9ug/g or 10ug/g.

Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5mol/L, preferably 0.1-0.4mol/L, more preferably 0.1-0.3mol/L, more preferably 0.1-0.2mol/L , more preferably 0.1-0.16 mol/L.

In the present invention, as described later, the viscosity of the solution is measured at 25°C using a rotational viscometer; the chloride ion content is measured according to the molar method in GB/T 15453-2008; the neodymium phosphonate solution The concentration was determined by complexometric titration. These methods are all documented in the open literature and will not be repeated here.

According to the present invention, the solvent in the neodymium phosphonate solution is preferably a preparation solvent, such as one or more of C ₅ -C ₁₀ alkanes, C ₅ -C ₁₀ cycloalkanes, and C ₆ -C ₁₂ aromatic hydrocarbons species, preferably one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene; particularly preferably For n-hexane.

According to the second aspect of the present invention, there is provided a method for preparing the above-mentioned neodymium phosphonate solution, wherein the method comprises: a step of contacting an aqueous solution of neodymium chloride, an organic phosphonate, an organic solvent and an alkaline compound, wherein the The molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4-6:1, and the amount of the basic compound is such that the pH value of the aqueous phase is less than or equal to 5.

According to the present invention, the aqueous solution of neodymium chloride can be obtained by reacting neodymium oxide with hydrochloric acid, or can be obtained by dissolving anhydrous neodymium chloride or neodymium chloride containing crystal water in water. The concentration of neodymium chloride is not particularly limited, as long as the neodymium chloride is completely dissolved. For example, the concentration of the aqueous solution of neodymium chloride may be 0.1-0.5 mol/L. In actual operation, since some manufacturers' neodymium oxide, anhydrous neodymium chloride or neodymium chloride containing crystalline water contain a very small amount of water-insoluble substances, in order to ensure the quality of subsequent products, filter paper is preferred in such cases Or stainless steel mesh to filter the neodymium chloride aqueous solution before use.

According to the present invention, preferably, the molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4-5:1. By setting the molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution within the above range, the catalyst activity can be further improved.

According to the present invention, preferably, the organic phosphonate is a structure represented by formula (1), wherein R ^d1 , R ^d2 and R ^d3 are each independently hydrogen, hydroxyl, C ₁ -C ₂₀ alkyl or C ₁ -C ₂₀ alkoxy, and at least one of R ^d1 , R ^d2 and R ^d3 is C ₁ -C ₂₀ alkyl or C ₁ - _{C 20} alkoxy; preferably R ^d1 , R ^d2 and R ^d3 are each independently hydroxyl, C ₄ -C ₁₂ alkyl or C ₄ -C ₁₂ alkoxy, and at least one of R ^d1 , R ^d2 and R ^d3 is C ₄ -C ₁₂ alkyl or C ₄ -C ₁₂ alkoxy group; more preferably, R ^d1 is a hydroxyl group, at least one of R ^d2 and R ^d3 is an alkyl or alkoxy group, and R ^d2 and R ^d3 are each independently selected from n-butyl, isobutyl Base, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethylpentyl, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl , n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 2-methyl Pentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy group, n-undecyloxy or n-dodecyloxy.

As a specific example of the organic phosphonate, for example, it can be selected from one or more of the compounds shown in the following formula:

In the formula (1), R ^d1 is a hydroxyl group, R ^d2 and R ^d3 are 2-ethylhexyloxy (i.e. two (2-ethylhexyl) phosphonate);

In formula (1), R ^d1 is a hydroxyl group, R ^d2 and R ^d3 are 2-ethylhexyl (being two (2-ethylhexyl) phosphinates);

In formula (1), R ^d1 is hydroxyl, R ^d2 is 2-ethylhexyl, and R ^d3 is 2-ethylhexyloxy (that is (2-ethylhexyl) mono-2-ethylhexyl phosphate) .

According to the present invention, the organic phosphonate compound can be obtained by a conventional method in the art, for example, it can be a commercial product, or can be prepared by a conventional method in the art, which is not particularly limited in the present invention.

According to the present invention, the organic solvent is a compound capable of dissolving neodymium organic phosphonate, such as one or more of C ₅ -C ₁₀ alkanes, C ₅ -C ₁₀ cycloalkanes and C ₆ -C ₁₂ aromatic hydrocarbons species, preferably one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene.

The amount of the above organic solvent is not particularly limited, preferably the amount of the organic solvent is such that the concentration of the final product is not higher than 0.5 mol/L. In addition, preferably, the amount of the organic solvent used is such that the volume of the organic phase and the volume of the aqueous phase are 0.3-2:1, more preferably 0.5-1:1.

According to the present invention, the contacting may be performed by mixing an aqueous solution of neodymium chloride, an organic phosphonate, an organic solvent and a basic compound, or two or more of them may be mixed together and then mixed with other components. In order to make the obtained neodymium phosphonate solution have lower viscosity and lower impurity content, preferably, the contacting includes: after making the aqueous solution of neodymium chloride contact with the organic phosphonate and the organic solvent for the first time, then using The product of the first contact is subjected to a second contact with a basic compound.

In the present invention, the first contact is used to fully dissolve the reaction raw materials. Preferably, the temperature of the first contact can be, for example, 5-80°C. From the perspective of energy saving, it is preferably at 10-50°C The first contact is made. In addition, the time for the first contact is not particularly limited, as long as the reaction raw materials can be well dissolved, for example, it can be more than 1 minute, preferably 1-5 minutes.

According to the present invention, preferably, the amount of the basic compound is such that the pH value of the aqueous phase is 4-5.

According to the present invention, the basic compound is itself or a substance with a pH value greater than 7 after being made into an aqueous solution, preferably one or more of hydroxide and ammonia water, more preferably sodium hydroxide, potassium hydroxide and ammonia water one or more of. For basic compounds in solid form, they are usually used as aqueous solutions. The concentration of the aqueous solution is not particularly limited, as long as it is fully dissolved, for example, it may be 0.1-5.0 mol/L.

Preferably, the aqueous solution of the alkaline substance is added in a dropping manner, and the dropping rate may be 2.0-20.0 mL/min, preferably 5.0-10.0 mL/min relative to 350 mL of the material to be dropped. If the dropping speed is too slow, the production efficiency will be too low; if the dropping speed is too fast, the product formation rate will be fast, which is not conducive to the final layering of the oil-water phase and the separation of impurities.

In the present invention, "relative to 350mL of the material to be dropped, the rate of addition can be 2.0-20.0mL/min" means that when the material to be dropped is 350mL, the rate of addition can be 2.0-20.0mL/min, while the rate of addition can be 2.0-20.0mL/min when the material to be dropped is When the material is 700mL, the dropping speed can be 4.0-40.0mL/min, so as to determine the dropping speed of different volumes of dropped materials.

According to the present invention, preferably, the second contact temperature is 30-80°C, more preferably 30-55°C, more preferably 45-55°C, especially preferably at 50°C, by performing at 50°C Take into account the reaction rate and save energy.

In addition, as the time for the second contact, as long as the reaction is sufficiently carried out, for example, it may be more than 1 hour, preferably 1-6 hours, more preferably 1-2 hours.

According to the third aspect of the present invention, the neodymium phosphonate solution prepared by the preparation method of the present invention is provided.

The neodymium phosphonate solution prepared according to the preparation method of the present invention has a solution viscosity measured at a concentration of 0.1mol/L at 25°C and is lower than 200mPa·s, and the chloride ion content in the neodymium phosphonate solution is When the concentration of neodymium phosphonate is 0.1mol/L, it is not higher than 10ug/g.

Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1mol/L at 25°C is lower than 100mPa·s; more preferably, the neodymium phosphonate solution is measured at a concentration of 0.1mol/L at 25°C. The solution viscosity measured at 0.1 mol/L is lower than 90 mPa·s; further preferably, the solution viscosity of the neodymium phosphonate solution measured at 25° C. at a concentration of 0.1 mol/L is 40-90 mPa·s.

Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 10 ug/g when the neodymium phosphonate concentration is 0.1 mol/L; more preferably, the chloride ion content is not higher than 10 ug/g when the neodymium phosphonate concentration is 0.1 When mol/L is not higher than 9ug/g; More preferably; Said chloride ion content is not higher than 8ug/g when phosphonate neodymium concentration is 0.1mol/L; More preferably; Said chloride ion content is in phosphine The concentration of neodymium phosphonate is not higher than 7ug/g when the concentration of neodymium phosphonate is 0.1mol/L; more preferably, the chloride ion content is 5-7ug/g when the concentration of neodymium phosphonate is 0.1mol/L.

Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5mol/L, preferably 0.1-0.4mol/L, more preferably 0.1-0.3mol/L, more preferably 0.1-0.2mol/L , more preferably 0.1-0.16 mol/L.

Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

According to the fourth aspect of the present invention, the application of the neodymium phosphonate solution of the present invention or the neodymium phosphonate solution prepared by the preparation method of the neodymium phosphonate solution of the present invention in the preparation of olefin polymerization catalysts is provided.

The present invention will be described in detail through examples below, but the present invention is not limited to the following examples.

In the following examples and comparative examples, the viscosity of the solution was measured at 25°C by a rotational viscometer, the content of chloride ions was measured by the molar method in GB/T 15453-2008, and the concentration of neodymium ions in the neodymium phosphonate solution was measured by complexometric titration To measure.

Example 1

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 200ml of n-hexane and 56g of bis(2-ethylhexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to add dropwise a concentration of 0.50mol/L sodium hydroxide aqueous solution into the flask through the constant pressure funnel, add 170ml dropwise (30min) and continue to react for 30min, and measure the pH value of the aqueous phase to be 4.0. Wherein, the molar ratio of phosphonate to neodymium is 5.8. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the viscosity of the solution at 25°C was measured to be 81mPa·s, the chloride ion content in the solution was 5.1ug/g, and the concentration was 0.148mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 3.4ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 42 mPa·s.

Example 2

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 200ml of n-hexane and 48g of bis(2-ethylhexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to drip a 0.50mol/L sodium hydroxide aqueous solution into the flask through a constant pressure funnel, add 180ml dropwise (30min) and continue to react for 30min, and measure the pH value of the aqueous phase to be 4.5. Wherein, the molar ratio of phosphonate to neodymium is 5.0. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the viscosity of the solution at 25°C was measured to be 131mPa·s, the chloride ion content in the solution was 6.4ug/g, and the concentration was 0.155mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 4.1ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 65 mPa·s.

Example 3

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 250ml of n-hexane and 40g of bis(2-ethylhexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to drip the sodium hydroxide aqueous solution with a concentration of 0.50mol/L into the flask through the constant pressure funnel, add 190ml dropwise (40min) and continue to react for 30min, and measure the pH value of the aqueous phase to be 5.0. Wherein, the molar ratio of phosphonate to neodymium is 4.1. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the viscosity of the solution at 25°C was measured to be 118mPa·s, the chloride ion content in the solution was 6.2ug/g, and the concentration was 0.118mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 5.3ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 87 mPa·s.

Example 4

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 200ml of n-hexane and 40g of bis(2-ethylhexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to drip the sodium hydroxide aqueous solution with a concentration of 0.50mol/L into the flask through the constant pressure funnel, add 190ml dropwise (40min) and continue to react for 30min, and measure the pH value of the aqueous phase to be 5.0. Wherein, the molar ratio of phosphonate to neodymium is 4.1. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the viscosity of the solution at 25°C was measured to be 198mPa·s, the chloride ion content in the solution was 7.4ug/g, and the concentration was 0.151mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 4.9ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 112 mPa·s.

Example 5

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 100ml of n-hexane and 52g of bis(2-ethylhexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to drip the sodium hydroxide aqueous solution whose concentration is 0.50mol/L into the flask through the constant pressure funnel, after dropping 170ml (taking 40min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.0. Wherein, the molar ratio of phosphonate to neodymium is 5.4. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the viscosity of the solution at 25°C was measured to be 369mPa·s, the chloride ion content in the solution was 9.8ug/g, and the concentration was 0.292mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 3.4ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 173 mPa·s.

Example 6

Add 120mL of 0.25mol/L neodymium chloride aqueous solution, 200ml of n-hexane and 56g of di(n-hexyl)phosphonate into a 1000mL three-necked flask, and heat to 50°C in a water bath. Turn on the stirring, then start to drip the sodium hydroxide aqueous solution whose concentration is 0.50mol/L into the flask through the constant pressure funnel, after dropping 170ml (taking 30min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.2. Wherein, the molar ratio of phosphonate to neodymium is 5.5. After the reaction is over, the layers are static, the oil-water phase is better separated, and the interface has no turbid impurities. The oil phase was separated, and the solution viscosity at 25°C was measured to be 108mPa·s, the chloride ion content in the solution was 7.2ug/g, and the concentration was 0.141mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 5.1ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 66 mPa·s.

Comparative example 1

Others are the same as in Example 1, only the amount of bis(2-ethylhexyl) phosphonate is changed to 36g, and the molar ratio of phosphonate to neodymium is 3.7. The pH of the aqueous phase was measured to be 3.5. After the reaction, the oil-water phase is difficult to separate after standing still, and there are many white unknown substances on the interface. The oil phase was drawn out, and the viscosity of the solution at 25°C was measured to be 12184mPa·s, the chloride ion content in the solution was 35.7ug/g, and the concentration was 0.124mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 28.8ug/g.

Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol/L with n-hexane, and the solution viscosity measured at 25° C. was 9840 mPa·s.

Comparative example 2

Others are the same as in Example 1, only the amount of aqueous sodium hydroxide solution is changed to 300mL, and the pH value of the aqueous phase is 6.5. After the reaction, it is very difficult to separate the oil-water phase after standing still, and it is basically difficult to observe an obvious interface. The oil phase was extracted, and the viscosity of the solution at 25°C was measured to be 8908mPa·s, the chloride ion content in the solution was 67.2ug/g, and the concentration was 0.082mol/L. When converted into a concentration of 0.1mol/L, the chloride ion content in the solution is 82.0ug/g.

Then, the obtained neodymium phosphonate solution was concentrated to 0.1 mol/L, and the solution viscosity measured at 25° C. was 11076 mPa·s.

The preferred embodiments of the present invention have been described in detail above, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims (10)

1. A neodymium phosphonate solution, characterized in that the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1mol/L at 25°C is lower than 200mPa·s, and the neodymium phosphonate solution The chloride ion content in the solution is not higher than 10ug/g when the concentration of neodymium phosphonate is 0.1mol/L. 2. The neodymium phosphonate solution according to claim 1, wherein the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1mol/L at 25°C is lower than 100mPa·s; Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7 ug/g when the concentration of neodymium phosphonate is 0.1 mol/L. 3. The neodymium phosphonate solution according to claim 1 or 2, wherein the concentration of the neodymium phosphonate solution is 0.04-0.5 mol/L, preferably 0.1-0.2 mol/L. 4. The neodymium phosphonate solution according to any one of claims 1-3, wherein the solvent of the neodymium phosphonate solution is n-hexane. 5. A method for preparing a neodymium phosphonate solution, characterized in that the method comprises: the step of contacting an aqueous solution of neodymium chloride, an organic phosphonate, an organic solvent and an alkaline compound, wherein the organic phosphonic acid The molar ratio of the ester to the neodymium chloride in the neodymium chloride aqueous solution is 4-6:1, and the amount of the basic compound makes the pH value of the aqueous phase less than or equal to 5. 6. The method according to claim 5, wherein said contacting comprises: after making the neodymium chloride aqueous solution and the organic phosphonate and the organic solvent carry out the first contact, then make the first contact product carry out the second contact with the basic compound touch; Preferably, the neodymium chloride content in the neodymium chloride aqueous solution is 0.1-0.5mol/L; Preferably, the molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4 to 5:1; Preferably, the organic phosphonate has a structure represented by formula (1), wherein R ^d1 , R ^d2 and R ^d3 are each independently hydrogen, hydroxyl, C ₁ -C ₂₀ alkyl or C ₁ -C ₂₀ , and at least one of R ^d1 , R ^d2 and R ^d3 is C ₁ -C ₂₀ alkyl or C ₁ -C ₂₀ alkoxy,

Preferably, in formula (1), R ^d1 is hydroxyl, R ^d2 and R ^d3 are both 2-ethylhexyloxy; Preferably, in formula (1), R ^d1 is hydroxyl, R ^d2 and R ^d3 are both 2-ethylhexyl; Preferably, in formula (1), R ^d1 is hydroxyl, R ^d2 is 2-ethylhexyl, and R ^d3 is 2-ethylhexyloxy; Preferably, the organic solvent is one or more of C ₅ -C ₁₀ alkanes, C ₅ -C ₁₀ cycloalkanes and C ₆ -C ₁₂ aromatics; Preferably, the organic solvent is one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene kind; Preferably, the amount of the organic solvent is such that the volume of the organic phase and the volume of the aqueous phase are 0.3˜2:1. 7. The method according to claim 5 or 6, wherein the amount of the basic compound makes the pH value of the aqueous phase 4 to 5; Preferably, the basic compound is used in the form of an aqueous solution, and the content of the basic compound in the aqueous solution of the basic compound is 0.1-5.0 mol/L; more preferably, the aqueous solution of the basic compound is added dropwise to the first contact product Carrying out the second contact; more preferably, the dropping rate is 2.0-20.0mL/min; Preferably, the basic compound is one or more of hydroxide and ammonia water. 8. The method according to any one of claims 6 or 7, wherein the second contact temperature is 30-80°C. 9. the neodymium phosphonate solution prepared by the preparation method of the neodymium phosphonate solution described in any one of claims 5-8; Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25°C is lower than 200 mPa·s, and the chloride ion content in the neodymium phosphonate solution is lower than that of the neodymium phosphonate solution. When the concentration is 0.1mol/L, it is not higher than 10ug/g; Preferably, the solution viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol/L at 25°C is lower than 100 mPa·s; Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7ug/g when the concentration of neodymium phosphonate is 0.1mol/L; Preferably, the concentration of the neodymium phosphonate solution is 0.04-0.5 mol/L, preferably 0.1-0.2 mol/L; Preferably, the solvent of the neodymium phosphonate solution is n-hexane. 10. The neodymium phosphonate solution described in any one of claims 1-4 or the neodymium phosphonate solution described in any one of claims 5-8 is prepared in the preparation of neodymium phosphonate solution Applications in Olefin Polymerization Catalysts.