SU1157797A1 - Method of producing solutions of cyclopentadiene ionic compounds - Google Patents

Abstract

1. METHOD FOR OBTAINING SOLUTIONS OF IONIC COMPOUNDS OF CYCLOPENTADIENE of general formula 1 + n (), Kt where Kt is a cation, electropositive metal or tetraalkylammonium; p is an integer equal to the metal valency of cyclopentadiene in an organic solvent medium, characterized in that, in order to simplify the process, the latter is carried out by electrolysis with a solution of cyclopentadiene in an anhydrous aprotic solvent on an iron cathode in the presence of a background electrolyte, using as an anode electrically positive metal. (L, 2. The method according to Claim 1, which means that the electrolysis is carried out with the separation of the cathode space from the anode diaphragm, which uses a cation-exchange membrane.; L 1 h1

Description

This invention relates to a process for the preparation of solutions of ionic compounds of cyclopentadiene (CPD) of general formula 1.

(SN;), Kt,

where Kt is an electropositive metal cation, or tetraalkammonium,

n is an integer equal to the valence of the metal,

which are used in the synthesis of various derivatives of CPD compounds having a wide range of applications,

The cyclopentadiene derivatives, especially cyclopentadiene derivatives of metals, are used as catalysts for the stereospecific polymerization of olefins, stabilizers and additives to motor and jet fuels, antiseptics, fungicides.

Electrochemical methods for the synthesis of CPD ionic compounds are unknown. There are two messages from the electrochemical synthesis of a metal-organic; ferrocene cyclopentadiene compounds consisting in the electrolysis of solutions of cyclopentadienyl thallium or cyclopentadiene in aprotic solvents on an iron anode in the presence of a background electrolyte. Ojj, HaKo, these methods cannot be considered as methods for the synthesis of compounds of the general formula (CgHy) Kt.

A known method for producing solutions of ionic compounds of cyclopentadiene of formula I, for example magnesium dicyclopentadienyl, consists in the methylation of cyclopentadiene with metallic magnesium in tetrahydrofuran in the presence of compound 5 of tetravalent titanium.

The disadvantages of this method:

the complexity of the process associated with the presence of large quantities of side products resulting from the use of threefold excess of metallic magnesium and tetravalent titanium compounds and the hydrogenation of the CPD to cyclopentane (1/3 of the initial CPD is consumed), as well as the duration of the process (maximum yield ( Su.H5) is reached only after 2 days;

use of scarce tetravalent titanium compounds;

972

explosion and fire hazards of the process, due to the nature of tetrahydrofuran and metal derivatives of cyclopentadiene.

The aim of the invention is to simplify the process technology by reducing the yield of by-products and increasing its productivity, and

also reducing its explosion and fire hazards.

The goal is achieved by the described method of obtaining solutions of ionic compounds of cyclopentadiene with the general form

1 by electrolysis of a solution of cyclopentadiene in an anhydrous aprotic solvent on an iron cathode in the presence of a background electrolyte using as an anode

electropositive metal.

Preferably the electrolysis is carried out with the separation of the cathode space from the anode diaphragm, c. which use the cation-exchange membrane. Halide muds of tetraalkylammonium are used as the background electrolyte. The electrolysis is carried out in anhydrous aprtonic solvents, mainly in acetonitrile CHjCN. The cathode is any metal or alloy resistant to cathodic polarization.

The mechanism for the electrochemical synthesis of compounds of formula 1 is

in the cathode reduction of CZC to the cyclopentadienyl anion and metal anodnomissolution:

+ e

40 "b

CgHj + H

. ,, -pe ,, + h Anode: Me anode.s-Me

-P

n CjH + Me 2

(s, n;) Kt

In the case of the diaphragm method, when no anodic dissolution of the metal occurs, Kt is the tetraalkylammonium cation AIK (cation of the background Q electrolyte).

If compounds having a reactivity are introduced into the reaction medium. a single halogen atom, such as RX, RV ECh, Xn, where R is alkyl, R is alkyl, aryl, E-Si, Sn, Ge; Me-Fe, Co, Ti, N1, Cr or other metals; X-SG, Br, the corresponding derivatives of cyclopentadiene are formed.

(s, n;) “Kt” A halogen-containing compound can be introduced in two ways: after the electrochemical generation of ionic compounds, the CPE; during electrochemical synthesis. Due to technological considerations, the second method is preferable, since the yield of the derivatives of the JRC in this case is higher (see examples 1,2,6,7). The low yield of products in the first case seems to be associated with partial interaction with the solvent. The by-products of the reaction are hydrogen, as well as halogen (Clj, wm, Br) (diaphragm method) or metal halides (diaphragm method). The number of metal halides forming strictly corresponds to the amount of electricity missed. The process is carried out at a temperature of 20-50 C. The synthesis at a temperature below 20 ° C is inexpedient, since this leads to a decrease in the electrical conductivity of the electrolyte solution, a rise in voltage on the terminals of the electrolyzer and correspondingly to unreasonable energy consumption. The upper temperature limit is the boiling point temperature of cyclopentadiene (42.5 ° C). As aprotic solvents, in addition to CHjCN, I can use I dimethyl sulfoxide, dimethyl formimide, pyridine, and others. Inert to diclopentadiene and its derivatives. Example 1. Synthesis of ethylcyclopentadiene - SdNuSuN; A solution of 12.5 ml of cyclopentadiene; and 1.03 g (0.1 mol) () 4MBr in 38.5 ml of CHjCN are subjected to electrolysis on an iron cathode and a magnesium anode at a current density (C) of 0.1 A / cm and a temperature of 25-30 ° C. After 10–15 mi after the current is switched on, ethyl bromide is started to be added dropwise to the reaction medium.

nRCyH ,, + KtX "

nR, + KtX

(C, H,),., - H Kt X, magnesium, which is removed from the electrolyte solution. After passing 1.18 A "h of electricity, the current is turned off and the drop of the haloalkyl continues for another 20 minutes. The total amount of ethyl bromide added is equivalent to the amount generated by stanza — Cj, Hj — in the synthesis process (determined by the amount of electricity missed, calculated on a solid-electron reduction process). The reaction mixture is then filtered off from magnesium salts and treated with pentane, the pentane solution is separated and the solvent is evaporated. 3.1 g are obtained, which makes up the output of the current and the substance 75%, bp 97-99 С (lit.: bp 96-98 ° C), and 4.04 g MdVg. (current output 100%). The process is carried out in a 100 ml glass cell; the cathode is an iron plate (steel of grade S.3), the anode is a magnesium plate with a working area of 12.5 cm, each, a voltage of 12-16 V, a distance between electrodes of 8-10 mm. During the electrolysis j, the solution is stirred with a glass blender. And pm. E 2. Synthesis of ethylcyclopentadiene. Different from. of Example 1 in that ethyl bromide is added to the cell after electrolysis in the amount of 9.6 g and the reaction mixture is kept under stirring for 1 hour. 2.44 g of C jHjCjHj are obtained, bp. 97-99 ° С (current and substance output 59%) and. 4.0 g MdVg (current output 100%). PRI me R 3. Synthesis of ethylcyclopentadiene. Differs from example 1 in that the process is carried out in dimethyl sulfoxide (daso) at the anode of aluminum. Receive, 2.0 g C H CjHj- output,%: current 48.3, substance 47.5) and 3.9 g AlBpj (current output 100%). Priker4. Synthesis of ethylcyclopentadiene. Differs from example 3 in that the process is carried out on a zinc anode. 5 Obtain 1.22 g C, (high,%: current 29.5, substance 29.0) and 3.2 g ZnBr (current output 100%. EXAMPLE 5. Synthesis of butylcyclo pentadiene -. It differs from Example 1 in that during the electrolysis process butyl bromide is added and the process is carried out at 3 A / cm and temperature. After passing 1,217 Ah of electricity, 3.92 g are obtained (yield,%: current 73, substance 72) , bp. 117-P9 ° C (lit.: pp5-P8s), and 4.0 g MdVg (current output 100%). EXAMPLE 6 Synthesis of trimethyl silyl cyclopentadiene - (CHj), SiCjH Differs from Example 1 in that trimethylchlorosilane (CH3) C5 | C1 is added and the process is carried out at 3 O, 05 A / cm. During the synthesis, magnesium chloride precipitates from the electrolyte solution. After 1,244 A. h., The solution is filtered, the salt and the mother liquor are treated with pentane, the pentane extracts are combined and the solvent is evaporated. ) 5SiCyH (yield,%: by current 99, by substance 98.5), bp 49–50 ° C / 30 mm Hg (lit., data: boiling batch mm Hg) , and 2,2 MgCI (current output 100%). EXAMPLE 7, Synthesis of Lilcyclopentadiene Trimetststi, Differs from Example 6 in that trimethylchlorosilane is added to the well after electrolysis, not 10.1 g is added and the reaction mixture is kept for 1 hour at 40 ° C and stirred. 5.19 g (CH,), (,%: current 81, substance 80.5 and 2.19 g MgCl (current output 100%) are obtained. EXAMPLE 8 Synthesis of trimethylsilylcyclopentadiene. Differs from the example 6 by the fact that the process is carried out at 20-22 C. Received .6,29 g (СН,), Si Sune (yield,%: current 98.8, substance 98.3) and 2.2 MgCl (current output 100%). EXAMPLE 9 Synthesis of trimethylsylcyclopentadiene Differs from Example 6 in that the process is carried out in a solution of 1.61 g (0.1 mol) of tetrabutylammonium bromide - (C4H,) 4N V. 31 t (CHj), Si GjHy (yield,%: on substances 76 and current 99.1) and 2.2 g MgCl, (current output 100%). EXAMPLE 10 Synthesis of trimethylsilylcyclopentad The electrolysis is carried out in a diaphragm electrolyzer at a current density of 0.05 A / cm, a temperature of 30-35 ° C and stirring of the electrolyte solution. A cation-exchange membrane is used as the diaphragm. The volume of catholyte and anolyte is 100 ml each. 12.5 ml of CPD and 1.03 g (0.1 mol) (C, Nu) of NBr in 38.5 ml of CHjCN; anolyte: solution of 1.03 g (C,., H5) of NBr in 50 ml of CHjCN. The cathode is an iron plate (working area (12.5 cm), the anode is graphite (12.5 cm). 10-15 minutes after the start of electrolysis, catholyte is added dropwise (CH,), SiCI, as in the example 1. After passing. 1.18 ACh of electricity, the catholyte solution is treated as in Example 6, and 6.31 g (CH), Si (yield,%: substance and current is 99.1 is obtained.) p 11. Synthesis of trimethylcyclopentadienyl tin -. (CH3) e Sn Differs from example 6 in that a saturated solution of trimethylchlorostannane - (CH), .SnCl in CHjCN is added. 7.49 g (CH,), Sn. ( output,%: by current 85.3, by substance 84), so kip 85-8 6 ° C / 10 mm Hg (lit.: boil 85 C / 100 mm Hg) and 2.19 g MgCl j (current output 100%). P 12 Synthesis of triethylcyclopentadienyl germanium (),. T., Differs from example 6 in that triethylgermanium is added - chloride (CjHy), GeC1. 7.13 g of GeCyHy are obtained (yield,%: current 83, substance 81, t. kip. 59-61 C / / 4 mm Hg (lit., data: bp 59-60 ° C / 5 mm Hg), and 2.21 g MgCl (current output 100%) . Example 13. Synthesis of ferrocene - CyU) Fe. -. : It differs from Example 6 in that anhydrous iron chloride — FeCl — is added every 5 min. After passing 1.1 A.h of electricity, 3.1 g of ferrocene (cc,%: current and substance 81) are obtained, m.p. . 172.5173 ° C lit.: so pl. 173lO, 5 ° C, and 1.95 g MgCl (current output 100%. 7 Example 14. Synthesis of ferrocene (CjHy) Fe in a diaphragm electrolyte. Differs from Example 10. In addition, anhydrous FeClj is added to the catholyte. After passing 1.12 Ah of electricity, 3.07 g of ferrocene is obtained (current and substance output 79. The obtained compounds were also identified by gas-liquid chromatography by comparing with known samples of 20% PMS-20000 on N-AW-HMDS, 1 2 m.) Example 15. Synthesis of titanium dicyclope tadienyl dichloride (CyHj) nci. A solution of 12.5 ml of 1 DIC and 1.03 g (0.1 mol) of (CjHj) NBr in 38.5 ml of CHjCN is subjected to electrolysis at an iron cathode and magnesium anode at a current density of 0.05 A / cm and a temperature of 25-30 C. After passing 1.2 Ah of electricity, the current is turned off and 4.4 g of titanium tetrachloride is added while stirring the electrolyte solution. magnesium salts. The solution is stirred for 1 hour. Then the liquid phase is filtered off, evaporated and the solid residue is treated with toluene. After distillation of toluene, floor 78; red crystals () TlClj, in the amount of 3.34 g (current and substance yield 60%), so pl. 287-289 ° C (lit., data 289 ± Zc), and 2.13 g of MgClg (current output 100%. Synthesis and allocation of the product are carried out in an atmosphere of dry argon. Example 16: Synthesis of cobalt dicyclopentadienyl chloride () CoCI differs from example 15 in that anhydrous cobalt trichloride is added in an amount of 3.7 g. 2.41 g (Cy5) 2 -CoCl is obtained (current and substance yield 65%. Found: C 53, 52 and 4.54; Co 25.80} Cl1 15.71. Calculated: C 53.45-, H 4.45; Co 26.28; C1 15.81. 2.1 g of MdSC are also obtained (yield current 100%). Thus, the proposed method of obtaining solutions of ionic compounds of cyclopentadiene of the general formula (C5Hy) Kt is a general method of synthesis of derivatives of cyclopentadiene, which advantageously differs from the prototype prostoytehnologiey, high performance, substantially smaller volume of the formed tsobochnyh products lack deficient catalysts, as well as relatively high vzrsho- and fire safety.

Claims (1)

1. METHOD FOR PRODUCING SOLUTIONS OF IONIC COMPOUNDS OF CYCLOPENTADIENE of general formula 1 (with ₅ n;) „Kt ^{+ h} , where Kt is a cation, an electropositive metal or tetraalkylammonium; η is an integer equal to the valency of the metal from cyclopentadiene in an organic solvent medium, characterized in that, in order to simplify the process technology, the latter is carried out by electrolysis with a solution of cyclopentadiene in an anhydrous aprotic solvent on an iron cathode in the presence of a background electrolyte, using as an anode electropositive _about metal. c, 2, The method of π. 1, the fact that the electrolysis is carried out with the separation of the cathode space from the anode diaphragm, which is used as a cation exchange membrane.