Phosphonate neodymium solution and preparation method and application thereof

Abstract

The present invention relates to the field of preparation of neodymium phosphonate, and discloses a neodymium phosphonate solution and a preparation method and application thereof. The neodymium phosphonate solution of the present invention is characterized in that the viscosity of the 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 not higher than 10 ug / g when the concentration of neodymium phosphonate is 0.1 mol / L. The neodymium phosphonate solution according to the present invention has the advantages of low viscosity and low impurity content, can be easily used in industrial production, and is particularly conducive to transportation and precise metering.

Description

Technical Field

[0001] The invention relates to the field of preparation of neodymium phosphonate, and in particular to a neodymium phosphonate solution and a preparation method and application thereof. Background Art

[0002] Phosphonates were used as extractants to extract metal elements from rare earths. Later, it was discovered by chance that neodymium phosphonates had the activity of catalyzing the polymerization of conjugated dienes, which attracted people's attention. The Changchun Institute of Applied Chemistry of the Chinese Academy of Sciences and Michelin have both conducted research on the catalysis of conjugated dienes by neodymium phosphonates, and products with high cis-1,4-structure content (>97%) can be obtained. It was also found that neodymium phosphonates can have catalytic activity at very low alkylating agent dosages ([Al] / [Nd]=5), while other neodymium salt systems have no catalytic activity at such low aluminum dosages. This feature makes its catalyst cost relatively low, creating favorable conditions for industrial applications.

[0003] At present, there are two methods for preparing neodymium phosphonate. One is the solid method. For example, CN1479753A records that the solid neodymium phosphonate obtained by this method cannot be completely dissolved in industrial commonly used solvents (alkanes, toluene, etc.), and the resulting catalyst is in the form of a viscous suspension. This heterogeneous catalyst will lead to low utilization efficiency of neodymium atoms on the one hand, and may cause transportation difficulties and inability to accurately measure on the other hand, which brings difficulties to industrial production. The second is the solution method, but due to the characteristics of neodymium phosphonate, its solution viscosity is relatively large, 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 water from the oil phase, which causes the neodymium phosphonate to contain a large amount of impurities, further affecting subsequent use. In addition, the high viscosity also makes the neodymium phosphonate particularly poor in fluidity, and it is jelly-like, which makes it difficult to accurately measure when it is used and cannot be used in industrial production.

[0004] In order to solve the problem of high viscosity, after the synthesis reaction is completed, CN103694378A adds a viscosity regulator to the phosphonate neodymium solution, such as di(2-ethylhexyl)phosphonate, 2-ethylhexylphosphonate-2-ethylhexyl ester, methylphosphonate dimethylheptyl ester, phosphonate tributyl ester, phosphonate triphenyl ester, phosphite dioctyl ester, phosphite diethyl ester, phosphite diphenyl ester, dimethyl phthalate, diethyl phthalate, dioctyl phthalate, one or more of the following, and the molar ratio of the viscosity regulator to the neodymium in the organic phosphonate neodymium is 0.25 to 3: 1. The addition of the viscosity regulator can significantly reduce the viscosity of the final product, but it cannot solve the problem of high impurity content caused by the difficulty of stratification during the synthesis process.

[0005] CN103224517A adds butadiene and / or isoprene and alcohols such as ethanol, propanol, butanol, hexanol, etc. to the oil phase. Although the viscosity of the solution is improved, the introduced alcohols are also impurities for subsequent use in rare earth catalysts. Summary of the invention

[0006] The purpose of the present invention is to provide a phosphonate neodymium solution and a preparation method and application thereof. The phosphonate neodymium solution of the present invention has the advantages of low viscosity and low impurity content.

[0007] In a first aspect, the present invention provides a neodymium phosphonate solution, wherein the 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 not higher than 10 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

[0008] 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.

[0009] Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

[0010] Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L, preferably 0.1-0.2 mol / L.

[0011] Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

[0012] According to a second aspect of the present invention, a method for preparing the above-mentioned phosphonate neodymium solution is provided, 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 molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 6:1, and the amount of the alkaline compound is such that the pH value of the aqueous phase is less than or equal to 5.

[0013] Preferably, the contacting comprises: bringing the aqueous solution of neodymium chloride into first contact with an organic phosphonate and an organic solvent, and then bringing the first contact product into second contact with an alkaline compound.

[0014] Preferably, the neodymium chloride content in the neodymium chloride aqueous solution is 0.1-0.5 mol / L.

[0015] Preferably, the molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 5:1.

[0016] Preferably, the organic phosphonate is a structure shown in formula (1), wherein Rd1 , R d2 and R d3 are independently hydrogen, hydroxyl, C1-C 20 Alkyl or C1-C 20 The alkoxy group, and R d1 , R d2 and R d3 At least one of them is C1-C 20 Alkyl or C1-C 20 The alkoxy group,

[0017]

[0018] Preferably, in formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyloxy.

[0019] Preferably, in formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyl.

[0020] Preferably, in formula (1), R d1 is hydroxyl group, R d2 is 2-ethylhexyl, R d3 It is 2-ethylhexyloxy.

[0021] Preferably, the organic solvent is C5-C 10 Alkanes, C5-C 10 Cycloalkanes and C6-C 12 one or more of aromatic hydrocarbons; more preferably, the organic solvent is one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene.

[0022] Preferably, the amount of the organic solvent used is such that the volume of the organic phase is 0.3 to 2:1 to the volume of the aqueous phase.

[0023] Preferably, the amount of the alkaline compound used makes the pH value of the aqueous phase be 4-5.

[0024] Preferably, the alkaline compound is used in the form of an aqueous solution, and the content of the alkaline compound in the aqueous solution is 0.1 to 5.0 mol / L; more preferably, the aqueous solution of the alkaline compound is added dropwise to the first contact product to carry out the second contact; more preferably, the dropping speed is 2.0 to 20.0 mL / min.

[0025] Preferably, the alkaline compound is one or more of hydroxide and ammonia water.

[0026] Preferably, the second contact temperature is 30-80°C.

[0027] According to a third aspect of the present invention, a neodymium phosphonate solution prepared by the preparation method of the present invention is provided.

[0028] 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 not higher than 10 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

[0029] 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.

[0030] Preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 7 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

[0031] Preferably, the concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L, preferably 0.1-0.2 mol / L.

[0032] Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

[0033] According to a fourth aspect of the present invention, there is provided use of the neodymium phosphonate solution of the present invention or the neodymium phosphonate solution prepared by the method for preparing the neodymium phosphonate solution of the present invention in preparing an olefin polymerization catalyst.

[0034] The neodymium phosphonate solution according to the present invention has the advantages of low viscosity and low impurity content, can be conveniently used in industrial production, and is particularly conducive to transportation and precise metering. DETAILED DESCRIPTION

[0035] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0036] In a first aspect, the present invention provides a neodymium phosphonate solution, wherein the 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 not higher than 10 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

[0037] 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 100 mPa·s; more preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol / L at 25°C is lower than 90 mPa·s; further preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol / L at 25°C is 40-90 mPa·s.

[0038] Specific values ​​of the solution viscosity of the neodymium phosphonate solution measured at 25°C at a concentration of 0.1 mol / L include, for example, 5 mPa·s, 10 mPa·s, 20 mPa·s, 30 mPa·s, 40 mPa·s, 42 mPa·s, 50 mPa·s, 60 mPa·s, 65 mPa·s, 70 mPa·s, 80 mPa·s, 87 mPa·s, 90 mPa·s, 100 mPa·s, 112 mPa·s, 130 mPa·s, 150 mPa·s, 173 mPa·s or 190 mPa·s.

[0039] According to the present invention, preferably, the chloride ion content in the neodymium phosphonate solution is not higher than 10ug / g when the concentration of neodymium phosphonate is 0.1mol / L; more preferably, the chloride ion content is not higher than 9ug / g when the concentration of neodymium phosphonate is 0.1mol / L; 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 chloride ion content is not higher than 7ug / g when the concentration of neodymium phosphonate is 0.1mol / L; further preferably, the chloride ion content is 5-7ug / g when the concentration of neodymium phosphonate is 0.1mol / L.

[0040] Specific values ​​of the chloride ion content include, for example, 1 ug / g, 2 ug / g, 3 ug / g, 4 ug / g, 5 ug / g, 6 ug / g, 7 ug / g, 8 ug / g, 9 ug / g or 10 ug / g.

[0041] Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L, preferably 0.1-0.4 mol / L, more preferably 0.1-0.3 mol / L, more preferably 0.1-0.2 mol / L, further preferably 0.1-0.16 mol / L.

[0042] In the present invention, as described below, the solution viscosity 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; and the concentration of the neodymium phosphonate solution is measured using a complexometric titration method. These methods are all described in public literature and will not be described in detail.

[0043] According to the present invention, the solvent in the neodymium phosphonate solution is preferably a preparation solvent, for example, C5-C 10 Alkanes, C5-C 10 Cycloalkanes and C6-C 12 One or more of the aromatic hydrocarbons, preferably one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene; particularly preferably n-hexane.

[0044] According to a second aspect of the present invention, a method for preparing the above-mentioned phosphonate neodymium solution is provided, 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 molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 6:1, and the amount of the alkaline compound is such that the pH value of the aqueous phase is less than or equal to 5.

[0045] According to the present invention, the aqueous solution of neodymium chloride can be obtained by reacting neodymium oxide with hydrochloric acid, or by dissolving anhydrous neodymium chloride or neodymium chloride containing crystal water in water. There is no particular restriction on the concentration of neodymium chloride, as long as the neodymium chloride is completely dissolved. For example, the concentration of the aqueous solution of neodymium chloride can be 0.1 to 0.5 mol / L. In actual operation, since some manufacturers' neodymium oxide, anhydrous neodymium chloride or neodymium chloride containing crystal water contain very small amounts of water-insoluble substances, in order to ensure the quality of subsequent products, in such cases, it is preferred to use filter paper or stainless steel mesh to filter the aqueous solution of neodymium chloride before use.

[0046] According to the present invention, preferably, the molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 5: 1. By making the molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride within the above range, the activity of the catalyst can be further improved.

[0047] According to the present invention, preferably, the organic phosphonate is a structure shown in formula (1), wherein R d1 , R d2 and R d3 are independently hydrogen, hydroxyl, C1-C 20 Alkyl or C1-C 20 The alkoxy group, and R d1 , R d2 and R d3 At least one of them is C1-C 20 Alkyl or C1-C 20 Alkoxy; preferably R d1 , R d2 and R d3 Each independently is hydroxyl, C4-C 12 Alkyl or C4-C12 The alkoxy group, and R d1 , R d2 and R d3 At least one of them is C4-C 12 Alkyl or C4-C 12 More preferably, R d1 is hydroxyl group, R d2 and R d3 At least one of them is an alkyl group or an alkoxy group, and R d2 and R d3 Each is independently selected from n-butyl, isobutyl, 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-methylpentyloxy, 2-ethylpentyloxy, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyloxy, n-octyl, n-nonyl, n-decyl, n-undecyloxy or n-dodecyloxy.

[0048]

[0049] Specific examples of the organic phosphonate may be selected from one or more of the compounds shown in the following formula:

[0050] In formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyloxy (i.e. di(2-ethylhexyl)phosphonate);

[0051] In formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyl (i.e. di(2-ethylhexyl)phosphinate);

[0052] In formula (1), R d1 is hydroxyl group, R d2 is 2-ethylhexyl, R d3 It is 2-ethylhexyloxy (ie, (2-ethylhexyl) mono-2-ethylhexyl phosphate).

[0053] According to the present invention, the organic phosphonate compound can be obtained by conventional methods in the art, for example, it can be a commercial product, or it can be prepared by conventional methods in the art, and the present invention has no particular limitation on this.

[0054] According to the present invention, the organic solvent is a compound capable of dissolving organic neodymium phosphonate, for example, C5-C 10 Alkanes, C5-C10 Cycloalkanes and C6-C 12 One or more of the aromatic hydrocarbons, preferably one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene.

[0055] The amount of the organic solvent is not particularly limited, and 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 is such that the volume of the organic phase to the volume of the aqueous phase is 0.3 to 2:1, more preferably 0.5 to 1:1.

[0056] According to the present invention, the contacting may be to mix the aqueous solution of neodymium chloride, the organic phosphonate, the organic solvent and the alkaline compound together, or to mix two or more of them and then mix them with other components. In order to make the obtained phosphonate neodymium solution have lower viscosity and lower impurity content, preferably, the contacting includes: after the aqueous solution of neodymium chloride is first contacted with the organic phosphonate and the organic solvent, the first contact product is second contacted with the alkaline compound.

[0057] 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, the first contact is preferably performed at 10-50° C. In addition, there is no particular limitation on the time of the first contact, as long as it can well dissolve the reaction raw materials, for example, it can be more than 1 minute, preferably 1-5 minutes.

[0058] According to the present invention, preferably, the amount of the alkaline compound used is such that the pH value of the aqueous phase is 4-5.

[0059] According to the present invention, the alkaline compound is a substance having a pH value greater than 7 by itself or after being prepared into an aqueous solution, preferably one or more of hydroxide and ammonia water, more preferably one or more of sodium hydroxide, potassium hydroxide and ammonia water. For alkaline compounds in solid form, they are usually prepared into an aqueous solution for use. There is no particular restriction on the concentration of the aqueous solution, as long as it is fully dissolved, for example, it can be 0.1 to 5.0 mol / L.

[0060] Preferably, the alkaline substance aqueous solution is added dropwise, and the dropping speed can be 2.0-20.0 mL / min, preferably 5.0-10.0 mL / min, relative to 350 mL of the material being dropped. If the dropping speed is too slow, the production efficiency is too low, and if the dropping speed is too fast, the product generation rate is fast, which is not conducive to the final stratification of the oil-water phase and the separation of impurities.

[0061] In the present invention, "relative to 350 mL of the material being dropped, the dropping acceleration can be 2.0 to 20.0 mL / min" means that when the material being dropped is 350 mL, the dropping acceleration can be 2.0 to 20.0 mL / min, and when the material being dropped is 700 mL, the dropping acceleration can be 4.0 to 40.0 mL / min, so as to determine the dropping acceleration of different volumes of material being dropped.

[0062] According to the present invention, preferably, the second contact temperature is 30-80°C, more preferably 30-55°C, more preferably 45-55°C, and particularly preferably 50°C. By carrying out the reaction at 50°C, both reaction rate and energy saving can be taken into account.

[0063] In addition, the second contact time may be any time as long as the reaction is sufficiently carried out, for example, it may be more than 1 hour, preferably 1-6 hours, and more preferably 1-2 hours.

[0064] According to a third aspect of the present invention, a neodymium phosphonate solution prepared by the preparation method of the present invention is provided.

[0065] The phosphonate neodymium solution prepared by the preparation method of the present invention has a solution viscosity of less than 200 mPa·s when measured at a concentration of 0.1 mol / L at 25°C, and the chloride ion content in the phosphonate neodymium solution is not higher than 10 ug / g when the phosphonate neodymium concentration is 0.1 mol / L.

[0066] Preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol / L at 25°C is lower than 100 mPa·s; more preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol / L at 25°C is lower than 90 mPa·s; further preferably, the viscosity of the neodymium phosphonate solution measured at a concentration of 0.1 mol / L at 25°C is 40-90 mPa·s.

[0067] 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; more preferably, the chloride ion content is not higher than 9ug / g when the neodymium phosphonate concentration is 0.1mol / L; more preferably; the chloride ion content is not higher than 8ug / g when the neodymium phosphonate concentration is 0.1mol / L; more preferably; the chloride ion content is not higher than 7ug / g when the neodymium phosphonate concentration is 0.1mol / L; further preferably, the chloride ion content is 5-7ug / g when the neodymium phosphonate concentration is 0.1mol / L.

[0068] Preferably, the neodymium ion concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L, preferably 0.1-0.4 mol / L, more preferably 0.1-0.3 mol / L, more preferably 0.1-0.2 mol / L, further preferably 0.1-0.16 mol / L.

[0069] Preferably, the solvent of the neodymium phosphonate solution is n-hexane.

[0070] According to a fourth aspect of the present invention, there is provided use of the neodymium phosphonate solution of the present invention or the neodymium phosphonate solution prepared by the method for preparing the neodymium phosphonate solution of the present invention in preparing an olefin polymerization catalyst.

[0071] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0072] In the following examples and comparative examples, the solution viscosity was measured at 25° C. using a rotational viscometer, the chloride ion content was measured according to the molar method in GB / T 15453-2008, and the neodymium ion concentration of the neodymium phosphonate solution was measured using a complexometric titration method.

[0073] Example 1

[0074] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 200ml of n-hexane and 56g of di(2-ethylhexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 170ml (taking 30min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.0. Among them, the molar ratio of phosphonate to neodymium is 5.8. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is 81mPa·s, the chloride ion content in the solution is 5.1ug / g, and the concentration is 0.148mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 3.4ug / g.

[0075] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 42 mPa·s.

[0076] Example 2

[0077] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 200ml of n-hexane and 48g of di(2-ethylhexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 180ml (taking 30min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.5. Among them, the molar ratio of phosphonate to neodymium is 5.0. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is measured to be 131mPa·s, the chloride ion content in the solution is 6.4ug / g, and the concentration is 0.155mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 4.1ug / g.

[0078] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 65 mPa·s.

[0079] Example 3

[0080] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 250ml of n-hexane and 40g of di(2-ethylhexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 190ml (taking 40min), continue to react for 30min, and measure the pH value of the aqueous phase to be 5.0. Among them, the molar ratio of phosphonate to neodymium is 4.1. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is measured to be 118mPa·s, the chloride ion content in the solution is 6.2ug / g, and the concentration is 0.118mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 5.3ug / g.

[0081] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 87 mPa·s.

[0082] Example 4

[0083] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 200ml of n-hexane and 40g of di(2-ethylhexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 190ml (taking 40min), continue to react for 30min, and measure the pH value of the aqueous phase to be 5.0. Among them, the molar ratio of phosphonate to neodymium is 4.1. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is measured to be 198mPa·s, the chloride ion content in the solution is 7.4ug / g, and the concentration is 0.151mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 4.9ug / g.

[0084] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 112 mPa·s.

[0085] Example 5

[0086] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 100ml of n-hexane and 52g of di(2-ethylhexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 170ml (taking 40min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.0. Among them, the molar ratio of phosphonate to neodymium is 5.4. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is 369mPa·s, the chloride ion content in the solution is 9.8ug / g, and the concentration is 0.292mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 3.4ug / g.

[0087] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 173 mPa·s.

[0088] Example 6

[0089] Add 120mL of 0.25mol / L aqueous solution of neodymium chloride, 200ml of n-hexane and 56g of di(n-hexyl)phosphonate to a 1000mL three-necked flask and heat to 50°C in a water bath. Start stirring, then start dripping 0.50mol / L aqueous solution of sodium hydroxide into the flask through a constant pressure funnel. After dripping 170ml (taking 30min), continue to react for 30min, and measure the pH value of the aqueous phase to be 4.2. Among them, the molar ratio of phosphonate to neodymium is 5.5. After the reaction is completed, the layers are statically separated, the oil-water phase is well separated, and there is no turbid impurity at the interface. Separate the oil phase, and the solution viscosity at 25°C is measured to be 108mPa·s, the chloride ion content in the solution is 7.2ug / g, and the concentration is 0.141mol / L. When converted to a concentration of 0.1mol / L, the chloride ion content in the solution is 5.1ug / g.

[0090] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 66 mPa·s.

[0091] Comparative Example 1

[0092] The rest is the same as in Example 1, except that the amount of di(2-ethylhexyl)phosphonate is changed to 36 g, wherein the molar ratio of phosphonate to neodymium is 3.7. The pH value of the aqueous phase is 3.5. After the reaction is completed, the oil-water phase is difficult to separate after standing, and there are many white unidentified substances on the interface. The oil phase is extracted, and the solution viscosity at 25°C is measured to be 12184 mPa·s, the chloride ion content in the solution is 35.7 ug / g, and the concentration is 0.124 mol / L. When converted to a concentration of 0.1 mol / L, the chloride ion content in the solution is 28.8 ug / g.

[0093] Furthermore, the obtained neodymium phosphonate solution was diluted to 0.1 mol / L with n-hexane, and the viscosity of the solution measured at 25° C. was 9840 mPa·s.

[0094] Comparative Example 2

[0095] The other conditions are the same as in Example 1, except that the amount of sodium hydroxide aqueous solution is changed to 300 mL, and the pH value of the aqueous phase is 6.5. After the reaction is completed, the oil-water phase is very difficult to separate after standing still, and it is basically difficult to observe a clear interface. The oil phase is extracted, and the solution viscosity is measured to be 8908 mPa·s at 25°C, the chloride ion content in the solution is 67.2 ug / g, and the concentration is 0.082 mol / L. When converted to a concentration of 0.1 mol / L, the chloride ion content in the solution is 82.0 ug / g.

[0096] Furthermore, the obtained neodymium phosphonate solution was concentrated to 0.1 mol / L, and the viscosity of the solution measured at 25° C. was 11076 mPa·s.

[0097] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A neodymium phosphonate solution, characterized in that The solution viscosity of the phosphonate neodymium 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 phosphonate neodymium solution is not higher than 10 ug / g when the phosphonate neodymium concentration is 0.1 mol / L, wherein the preparation method of the phosphonate neodymium solution comprises: a step of contacting an aqueous solution of neodymium chloride, an organic phosphonate, an organic solvent and an alkaline compound, wherein the molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 6:1, and the amount of the alkaline compound is such that the pH value of the aqueous phase is less than or equal to 5.

2. The neodymium phosphonate solution according to claim 1, wherein The solution viscosity of the neodymium phosphonate solution measured at 25° C. with a concentration of 0.1 mol / L is lower than 100 mPa·s.

3. The neodymium phosphonate solution according to claim 1, wherein The chloride ion content in the neodymium phosphonate solution is not higher than 7 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

4. The neodymium phosphonate solution according to any one of claims 1 to 3, wherein The concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L.

5. The neodymium phosphonate solution according to claim 4, wherein The concentration of the neodymium phosphonate solution is 0.1-0.2 mol / L.

6. The neodymium phosphonate solution according to any one of claims 1 to 3, wherein The solvent of the neodymium phosphonate solution is n-hexane.

7. A method for preparing a neodymium phosphonate solution, characterized in that: The method comprises the steps of contacting a neodymium chloride aqueous solution, an organic phosphonate, an organic solvent and an alkaline compound, wherein the molar ratio of the organic phosphonate to the neodymium chloride in the neodymium chloride aqueous solution is 4 to 6:1, and the amount of the alkaline compound is such that the pH value of the aqueous phase is less than or equal to 5. The organic phosphonate is a structure shown in formula (1), wherein R d1 , R d2 and R d3 are independently hydrogen, hydroxyl, C1-C 20 Alkyl or C1-C 20 The alkoxy group, and R d1 , R d2 and R d3 At least one of them is C1-C 20 Alkyl or C1-C 20 The alkoxy group, 8. The method according to claim 7, wherein: The contacting comprises: making the aqueous solution of neodymium chloride contact with the organic phosphonate and the organic solvent for the first time, and then making the first contact product contact with the alkaline compound for the second time.

9. The method according to claim 8, wherein: The content of neodymium chloride in the neodymium chloride aqueous solution is 0.1-0.5 mol / L.

10. The method according to claim 8, wherein: The molar ratio of the organic phosphonate to the neodymium chloride in the aqueous solution of neodymium chloride is 4 to 5:

1.

11. The method according to claim 8, wherein: In formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyloxy.

12. The method according to claim 8, wherein: In formula (1), R d1 is hydroxyl group, R d2 and R d3 All are 2-ethylhexyl.

13. The method according to claim 8, wherein: In formula (1), R d1 is hydroxyl group, R d2 is 2-ethylhexyl, R d3 It is 2-ethylhexyloxy.

14. The method according to claim 8, wherein: The organic solvent is C5-C 10 Alkanes, C5-C 10 Cycloalkanes and C6-C 12 One or more of the aromatic hydrocarbons.

15. The method according to claim 14, wherein: The organic solvent is one or more of hexane, cyclohexane, heptane, pentane, isopentane, octane, methylcyclohexane, benzene, toluene, xylene and cumene.

16. The method according to claim 8, wherein: 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 to 2:

1.

17. The method according to any one of claims 8 to 16, wherein: The amount of the alkaline compound used is such that the pH value of the aqueous phase is 4-5.

18. The method according to claim 17, wherein: The alkaline compound is used in the form of an aqueous solution, and the content of the alkaline compound in the aqueous solution of the alkaline compound is 0.1 to 5.0 mol / L.

19. The method according to claim 18, wherein: The second contact is performed by adding the aqueous solution of the basic compound dropwise to the first contact product.

20. The method according to claim 19, wherein: The dropping speed is 2.0 to 20.0 mL / min.

21. The method according to claim 8, wherein: The alkaline compound is one or more of hydroxide and ammonia water.

22. The method according to any one of claims 8 to 16, wherein: The second contact temperature is 30-80°C.

23. The neodymium phosphonate solution prepared by the method for preparing the neodymium phosphonate solution according to any one of claims 7 to 22.

24. The neodymium phosphonate solution according to claim 23, 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 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.

25. The neodymium phosphonate solution according to claim 23, wherein The solution viscosity of the neodymium phosphonate solution measured at 25° C. with a concentration of 0.1 mol / L is lower than 100 mPa·s.

26. The neodymium phosphonate solution according to claim 23, wherein The chloride ion content in the neodymium phosphonate solution is not higher than 7 ug / g when the neodymium phosphonate concentration is 0.1 mol / L.

27. The neodymium phosphonate solution according to claim 23, wherein The concentration of the neodymium phosphonate solution is 0.04-0.5 mol / L.

28. The neodymium phosphonate solution according to claim 27, wherein The concentration of the neodymium phosphonate solution is 0.1-0.2 mol / L.

29. The neodymium phosphonate solution according to claim 23, wherein The solvent of the neodymium phosphonate solution is n-hexane.

30. Use of the neodymium phosphonate solution prepared by the method for preparing the neodymium phosphonate solution according to any one of claims 1 to 6 or any one of claims 7 to 22 in preparing an olefin polymerization catalyst.

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