RU2438981C2 - Method of producing alcohol solvates of chlorides of rare-earth elements - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry when producing diene polymerisation catalysts. Aqueous chloride of a rare-earth element is mixed with monoatomic alcohol in molar ratio alcohol: rare-earth element equal to (100-200):1. The azeotropic mixture is distilled at normal pressure, followed by distillation of excess alcohol in the presence of paraffin with initial boiling point of 220-270°C in a rotary film evaporator. The ready product is a stable mobile dispersion of a solvate of a chloride of a rare-earth element in liquid paraffin.

EFFECT: invention simplifies the process, cuts the duration of the process and enables to obtain a highly active diene polymerisation catalyst.

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Description

The invention relates to methods for producing alcohol solvates of rare-earth chloride chlorides (REE) used as components of diene polymerization catalysts, and may find application in the production of cis-1,4-homopolymers and cis-1,4-copolymers in the synthetic rubber industry.

A known method for producing alcohol solvates of REE chlorides by reacting REE oxides with a hydrochlorinating agent in a monohydric aliphatic alcohol with a mass ratio of alcohol (ROH) to oxide of 5 to 80 (US Pat. RU 2039709, C01F 17/00, B01J 27/10, priority from 26 11.92). As the hydrochlorinating compound, hydrogen chloride in the form of a solution in monohydric alcohol, piperylene hydrochloride or isoprene hydrochloride is used. The interaction is carried out with stirring and a temperature of 25-80 ° C for 1-24 hours, resulting in the formation of REE chlorides in the form of a solution in alcohol. Then, oil or liquid paraffin with a boiling point of 220-270 ° C is added to the solution, and the alcohol is removed in an evaporator with a stirrer or in a rotary film evaporator (EPI).

The resulting dispersions of alcohol solvates of REE chlorides are fairly uniform in alcohol content. The composition of the obtained products is characterized by a molar ratio of NdCl ₃ : ROH equal to 1: 2.95 ÷ 3.1.

The disadvantage of this method is that in the process of synthesis of solvates of REE chlorides, side reactions still occur, which leads to contamination of the product with REE oxychlorides (from 0.5 to 2.4% by weight). This reduces the yield of the target product and adversely affects the quality of the catalysts for the polymerization of dienes obtained using it.

Thus, according to the authors of this application, in 30 minutes of isoprene polymerization in the presence of a catalyst based on NdCl ₃ · 2.95ROH synthesized according to the procedure described in example 1 of this patent, and with a molar ratio of monomer: catalyst equal to 10000: 1, is formed only 45% of the polymer. The content of cis-1,4-units in polyisoprene is 97%.

In addition, the use of hydrochlorinating agents for synthesis requires special anti-corrosion equipment and complicates the process design. A known method for producing alcohol solvate of lanthanide halides, comprising the following stages:

- dissolution of hydrated lanthanide halide in absolute ethanol;

- removal of ethanol by distillation in vacuum;

- re-dissolving the resulting product in an absolute oxygen-containing organic solvent selected from the group consisting of tetrahydrofuran, methanol and ethanol;

- adding an electron-donor compound selected from the group consisting of C ₂ -C ₂₀ monohydric aliphatic alcohols, C _4-20 alkyl cellulose, tetrahydrofuran, organophosphorus compounds of the general formula R ₃ PO, R ₂ (RO) PO, R (RO) ₂ PO or ( RO) ₃ RO;

- separation of the obtained complex compound from an oxygen-containing solvent by vacuum distillation and its dissolution in absolute hexane or toluene (ed. certificate of the USSR 148623, С08F 4/52, С08F 136/08, priority from 10/18/79).

After adding piperylene and an organoaluminum compound (for example, triethylaluminum, diisobutylaluminium hydride, triisobutylaluminum) to the resulting solution of the solvate of the lanthanide solvate, a catalyst is formed which, immediately after preparation, can be used for polymerization of isoprene in a hydrocarbon medium.

The disadvantage of this method is the need to use absolute toluene, hexane and alcohol as solvents, and the amount of the latter is a large molar ratio of absolute alcohol to lanthanide chloride of 515. In addition, the two-time removal of the solvent alcohol requires the use of vacuum technology. It should also be noted that catalysts based on the synthesized in a known manner alcohol solvate of lactanoid halides are characterized by insufficient efficiency. So, to achieve 75-81% conversion of isoprene to polymer with a molar ratio of monomer: laptanoid equal to 8000: 1, it takes 2.5 hours (see examples 8, 9 of the patent description).

The most mucilous analogue in technical essence to the proposed method is a method for producing an alcohol solvate of rare-earth chloride chloride used to prepare a diene polymerization catalyst (US Pat. RU 2220909, С01F 17/00, priority date 12.02.02). In a device equipped with a mixing device, load six-water neodymium chloride (NdCl ₃ · 6H ₂ O) and fill in n-butyl alcohol (BS). Then, with stirring, at a temperature of 50-60 ° C and a pressure of 30-50 mm Hg. carry out the distillation of the azeotropic mixture and excess alcohol. The obtained anhydrous 20-25 wt.% Butanol solution of neodymium chloride is diluted with isopropyl alcohol heated to 60-80 ° C to a concentration of 6 wt%. The molar ratio of the mixture of alcohols to neodymium is 70 ÷ 95: 1. Then, in the presence of liquid paraffin with a boiling point of 220-270 ° C, excess alcohol is distilled off in a rotary-film apparatus to obtain a dispersion of the alcohol solvate of neodymium chloride in liquid paraffin. The molar ratio of the sum of alcohols to neodymium in the target product is 2.5 ÷ 3: 1. Moreover, the proportion of butyl alcohol in the amount of alcohols is 13-15% (mol.). If necessary, add the missing amount of alcohol to the resulting product. Then, within 6 hours, with stirring, a suspension of neodymium chloride solvate ripens, after which the product is used to synthesize an isoprene polymerization catalyst.

Despite the fact that this method eliminates the formation of by-products, does not impose high requirements on the moisture content of the alcohols used, it has several disadvantages. First, it requires a long exposure (for 6 hours) of the resulting suspension of neodymium chloride solvate before its use as a component of the diene polymerization catalyst. Secondly, to carry out the stage of distillation of the azeotropic butanol-water mixture and excess alcohol, the use of a vacuum technique and mandatory control of the concentration of the product in the solution are required, since its further dilution with isopropyl alcohol should be carried out to a certain concentration (6% wt.). In this case, isopropyl alcohol is preheated almost to a boil. It should also be noted that the polymerization catalysts obtained on the basis of solvates of neodymium chloride, synthesized in this way, do not have a sufficiently high activity (see control example 8).

The objective of the proposed technical solution is to simplify and accelerate the method of obtaining solvates of REE chlorides, capable of forming highly effective polymerization catalysts of conjugated dienes.

The problem is solved in that in the known method for producing an alcohol solvate of rare-earth chloride, comprising mixing a rare-earth aqueous chloride with monohydric alcohol, distilling an azeotropic mixture and subsequent distilling off excess alcohol in the presence of liquid paraffin with a boiling point of 220-270 ° C in a rotor film evaporator, a mixture of the aqueous chloride of the rare-earth element with monohydric alcohol is carried out at a molar ratio of alcohol: REE equal to 100 ÷ 200: 1, and azeotropic distillation is carried out and normal pressure.

The essence of the proposed method lies in the fact that in an apparatus equipped with a stirrer and a jacket for heating, an aqueous solution of REE chloride and the estimated amount of monohydric alcohol are set. Mixing is turned on, the mixture is heated to boiling, and REE chloride is completely dissolved in alcohol, and the azeotropic alcohol-water mixture is distilled off under normal pressure. Then, the REE chloride solvate solution is mixed with liquid paraffin with a boiling point of 220-270 ° C. Isolation of the product in the form of a suspension in liquid paraffin is carried out in a rotary film evaporator. The obtained solvate of REE chloride is analyzed for the content of metal, alcohol and water and is used to prepare a diene polymerization catalyst. The REE chloride solvate has the following REE molar composition: alcohol: water = 1: 2 ÷ 2.8: 0.2 ÷ 1.5. The molar ratio of the sum of donors in the complex to REE is 2.8 ÷ 3.8: 1.

As aqueous REE chlorides, individual metal chlorides can be used, for example, 6-aqueous neodymium chloride (NdCl ₃ · 6H ₂ O);

7-praseodymium chloride (PrCl ₃ · 6H ₂ O);

6-gadolinium chloride chloride (GdCl ₃ · 6H ₂ O), supplied to the Russian market, for example, CJSC "Vecton" or LLC "Stigma",

and synthesized from technical mixtures of REE oxides with a neodymium content of at least 85% of the total amount of metals, for example, from Didim, manufactured according to TU AD 11.46-89 (LdCl ₃ · 6H ₂ O).

As monohydric alcohols, isopropyl, n-butyl, cyclohexyl alcohols can be used.

The molar ratio of alcohol: REE in the initial mixture is most preferably in the range of 100 ÷ 200: 1.

Reducing the dosage of alcohol leads to a decrease in the activity of the catalyst obtained on the basis of the synthesized solvates, as well as to the necessity of introducing the stage of maturation of the suspension of the solvate.

An increase in the dosage of alcohol is simply not economically feasible.

The following are examples illustrating the proposed method.

Example 1

214.5 L of isopropyl alcohol (IPA) is poured into an apparatus equipped with a stirrer and a heating jacket and 10 kg of NdCl ₃ · 6H ₂ O are loaded. The molar ratio of IPA to neodymium is 100: 1.

Stirring is turned on and the mixture is brought to a boil under normal pressure. Complete dissolution of neodymium chloride in alcohol takes place and an azeotropic mixture of water with IPA is distilled off. Then, the solution of neodymium chloride solvate in IPA is mixed with 60 kg of liquid paraffin with a boiling point of 220-270 ° C, and the excess alcohol is distilled off in a rotary-film evaporator.

The finished product is a stable mobile dispersion of solvate of neodymium chloride in liquid paraffin and has the composition NdCl ₃ · 1,8IPS · 1,5H ₂ O.

Example 2

In a device equipped with a stirrer and a heating jacket, 10 kg of PrCl ₃ · 7H ₂ O are loaded and 489.7 L of n-butyl alcohol (BS) is poured, the molar ratio of BS to praseodymium is 200: 1.

With stirring and normal pressure, the mixture is brought to a boil, and an azeotropic mixture of water with BS is distilled off.

Then, a solution of the solvate of praseodymium chloride in BS is mixed with 80 kg of liquid paraffin with a boiling point of 220-270 ° C, and the excess alcohol is distilled off in a rotary-film evaporator.

The finished product is a stable mobile dispersion of solvate of praseodymium chloride in liquid paraffin and has the composition PrCl ₃ · 2.6BS · 0.2H ₂ O.

Example 3

343.6 L of cyclohexyl alcohol (CA) is poured into a device with a stirrer and a heating jacket and 10 kg of GdCl ₃ · 6H ₂ O are loaded.

The molar ratio of CS to gadolinium is 120: 1.

With stirring and normal pressure, the mixture is brought to a boil and the water-alcohol azeotrope is distilled off.

Then, a solution of the solvate of gadolinium chloride in CS is mixed with 70 kg of liquid paraffin and the excess alcohol is distilled off in a rotary-film evaporator.

The finished product - a mobile dispersion of gadolinium chloride solvate in liquid paraffin - has the composition GdCl ₃ · 2CS · 0.8N ₂ O.

Example 4

321.7 L of isopropyl alcohol (IPA) is poured into an apparatus with a stirrer and a heating jacket and 10 kg of REE chlorides (LdCl ₃ · 6Н ₂ О) obtained from a mixture of REE oxides under the trade name "Didim" are loaded. The molar ratio of IPS to the amount of REE is 150: 1.

With stirring and normal pressure, the mixture is heated to boiling and the water-alcohol azeotrope is distilled off. Then, a solution of the REE chloride solvate in IPA is mixed with 80 kg of liquid paraffin, and the excess alcohol is distilled off in a rotary film evaporator.

The dispersion of the solvate of REE chloride in liquid paraffin has the composition LdCl ₃ · 2,8IPS · 1,0Н ₂ O.

Obtained by the proposed method, solvates of REE chlorides in liquid paraffin are used to prepare catalysts for the (co) -polymerization of butadiene and isoprene.

Example 5

Preliminarily heated in a vacuum at 200 ° C and filled with dry inert gas, a neodymium chloride solvate dispersion in liquid paraffin obtained in Example 1 is placed. Then piperylene and a solution of triisobutylaluminum in toluene are added with stirring. The molar ratio of neodymium: piperylene: triisobutylaluminum in the catalyst is 1: 2: 12,

A glass ampoule heated in a vacuum at 200 ° C and filled with dry inert gas is loaded with a solution of isoprene in isopentane, thermostated at 20 ° C, and the catalyst is fed with stirring at a molar ratio of isoprene to neodymium of 10,000: 1.

The polymer yield in 30 minutes is 72.5%. The content of cis-1,4 units is 98.5%.

Example 6

The gadolinium chloride solvate dispersion in liquid paraffin prepared in Example 3 was placed in the reactor prepared according to Example 5, and then, butadiene and a solution of triisobutylaluminum in toluene were added with stirring. The molar ratio of gadolinium: butadiene: triisobutylaluminum in the catalyst is 1:10:15.

In a glass ampoule heated in a vacuum at 200 ° C and filled with an inert gas, a solution of butadiene in gasoline is loaded, thermostatted at 50 ° C and the catalyst is fed with stirring at the calculation of the molar ratio of butadiene to gadolinium 15000: 1.

The output of polybutadiene in 30 minutes is 92%.

The content of cis-1,4-units is 99%, trans-1,4-units - 0.8%, 1.2-units - 0.2%.

Example 7

In the reactor prepared according to Example 5, a Didim chloride solvate dispersion in liquid paraffin obtained in Example 4 is placed, and then piperylene and triisobutylaluminum are added with stirring. The molar ratio of REE: piperylene: triisobutylaluminum in the catalyst is 1: 5: 15.

In a glass ampoule prepared according to Example 5, a solution of a mixture of butadiene with isoprene in cyclohexane is loaded, thermostatted at 50 ° C and the catalyst is fed at the rate of 15000: 1 molar ratio of monomer mixture to Didim. The copolymer yield in 30 minutes is 85%.

The content of cis-1,4-units is 98.5%, trans-1.4-units 1.0%, 1.2-units 0.5%.

Example 8 (control)

Prepared in example 5, the reactor is placed a dispersion of solvate of neodymium chloride (composition: NdCl ₃ · 0,35BS · 2,4IPS) in liquid paraffin obtained by the method described in example 2 US Pat. RU 2220909. Then, piperylene and a solution of triisobutylaluminum in toluene are added with stirring. The molar ratio of neodymium: piperylene: triisobutylaluminum in the catalyst is 1: 2: 12.

In a glass ampoule prepared according to Example 5, a solution of isoprene in isopentane is loaded, thermostated at 20 ° C and the catalyst is fed with stirring at the rate of 10000: 1 molar ratio of isoprene to neodymium. The polymer yield in 30 minutes is 65%. The content of cis-1,4-units is 97.0%.

Example 9 (control)

Prepared in example 5, the reactor is placed a dispersion of neodymium chloride solvate of the composition NdCl ₃ · 0.4BS · 2.2IPS in liquid paraffin obtained by the method described in example 1 of patent RU No. 2220909 using azeotropic distillation of the race under reduced pressure. Then, piperylene and a solution of triisobutylaluminum are added with stirring.

The molar ratio of REE: piperylene: triisobutylaluminum in the catalyst is 1: 5: 15.

In a glass ampoule prepared according to Example 5, a solution of a mixture of butadiene with isoprene in cyclohexane is loaded, thermostated at 50 ° C and the catalyst is fed at a molar ratio of isoprene to REE of 15000: 1. The copolymer yield in 30 minutes is 70%.

Example 10 (control).

193.1 l of isopropyl alcohol is poured into an apparatus equipped with a stirrer and a heating jacket and 10 kg of NdCl ₃ · 6H ₂ O are loaded. The molar ratio of isopropyl alcohol to neodymium is 90: 1. Mixing is turned on, and at normal pressure, the mixture is brought to a boil and the water-alcohol azeotrope is distilled off. Then, a solution of neodymium chloride solvate in IPA is mixed with 60 kg of liquid paraffin with a boiling point of 220-270 ° C and the excess alcohol is distilled off in a rotary-film evaporator.

The finished product is a dispersion of solvate of neodymium chloride in liquid paraffin - has the composition NdCl ₃ · 1,0IPS · 2,4H ₂ O.

The resulting neodymium chloride solvate dispersion is placed in the reactor prepared according to Example 5. The catalyst is then prepared by adding piperylene and a solution of triisobutylaluminum to the reactor with stirring. The molar ratio of REE: piperylene: triisobutylaluminum in the catalyst is 1: 5: 15.

In a glass ampule prepared according to Example 5, a solution of isoprene in isopentane is loaded, thermostated at 20 ° C and the catalyst is supplied. The molar ratio of isoprene to neodymium is 10,000: 1.

The polymer yield in 30 minutes is 59%.

Thus, the proposed method allows to simplify and accelerate the process of obtaining solvates of REE chlorides, since the stages of additional introduction of monohydric alcohol and soaking a suspension of solvate of REE chloride for 6 hours are excluded, and azeotropic distillation does not require the use of vacuum equipment. The catalysts obtained on the basis of solvates synthesized by the proposed method have high activity.

Claims (1)

A method for producing alcohol solvates of rare-earth chloride chlorides, comprising mixing an aqueous rare-earth chloride with a monohydroxy alcohol, distilling an azeotropic mixture and then distilling off the excess alcohol in the presence of liquid paraffin with a boiling point of 220-270 ° C in a rotary-film evaporator, which consists in mixing is carried out at a molar ratio of alcohol: rare earth element equal to 100 ÷ 200: 1, and azeotropic distillation is carried out at normal pressure.