Method for producing organic tellurium compound and method for producing vinyl polymer

Abstract

Provided is a method for producing an organic tellurium compound that enables the production of an organic tellurium compound in high yield using metallic tellurium as a source material and produces less amount of side products. A method for producing an organic tellurium compound includes the steps of: (A) reacting metallic tellurium with a compound represented by a general formula (1) below; and (B) reacting a compound obtained by the step (A) with an organic halogen compound, the metallic tellurium having a copper content of less than 100 ppm,
M(R.sup.1)m   Formula (1)
where R.sup.1 represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, M represents an alkali metal or an alkaline earth metal, m represents 1 when M is an alkali metal, and m represents 2 when M is an alkaline earth metal.

Claims

1. A method for producing an organic tellurium compound, the method comprising the steps of: (A) reacting metallic tellurium with a compound represented by formula (1) below; and (B) reacting a compound obtained by the step (A) with an organic halogen compound, the metallic tellurium having a copper content of not less than 0.1 ppm and less than 100 ppm and an oxygen content of not less than 0.1 wt. % and less than 3 wt. %,
M(R.sup.1)m   Formula (1) where R.sup.1 represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, M represents an alkali metal or an alkaline earth metal, m represents 1 when M is an alkali metal, and m represents 2 when M is an alkaline earth metal.

2. The method for producing an organic tellurium compound according to claim 1, wherein the organic halogen compound is at least one selected from the group consisting of a compound represented by formula (2-1) below and a compound represented by formula (2-2) below, ##STR00009## where R.sup.2 and R.sup.3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R.sup.4 represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group or a propargyl group, and X.sup.1 represents a halogen atom, ##STR00010## where R.sup.5 and R.sup.6 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, X.sup.2 represents a halogen atom, R.sup.7 represents an alkylene group having 1 to 8 carbon atoms, an arylene group, an amide group or an ester group, n is an integer of 2 to 4, and R.sup.8 represents a divalent single bond or a divalent organic group when n is 2, represents a trivalent organic group when n is 3, and represents a tetravalent organic group when n is 4.

3. The method for producing an organic tellurium compound according to claim 1, wherein a usage rate of the compound represented by the general formula (1) is 0.5 mol to 1.5 mol per mole of the metallic tellurium.

4. The method for producing an organic tellurium compound according to claim 1, wherein a usage rate of the organic halogen compound is 0.5 mol to 6 mol per mole of the metallic tellurium.

5. The method for producing an organic tellurium compound according to claim 1, wherein a specific surface area of the metallic tellurium is 0.5 m.sup.2/g to 2.0 m.sup.2/g.

6. The method for producing an organic tellurium compound according to claim 1, wherein the step (A) is performed by suspending the metallic tellurium in a solvent.

7. A living radical polymerization initiator being an organic tellurium compound obtained by the method according to claim 1.

8. A method for producing a vinyl polymer, the method comprising the step of polymerizing a vinyl monomer by living radical polymerization using the organic tellurium compound obtained by the method according to claim 1 to synthesize a vinyl polymer.

9. A vinyl polymer produced by the method for producing a vinyl polymer according to claim 8.

10. The method for producing an organic tellurium compound according to claim 1, wherein the steps (A) and (B) are performed under an inert gas atmosphere.

Description

EXAMPLES

(1) Hereinafter, a detailed description will be given of the present invention with reference to examples, but the present invention is not limited to these examples.

(2) The oxygen content of metallic tellurium was obtained by measuring the tellurium content with an X-ray fluorescence spectrometer (trade name: ZSX Primus II, manufactured by Rigaku Corporation) and making a calculation regarding the remaining component as oxygen.

(3) The copper content of metallic tellurium was measured, after the heating of the metallic tellurium to melt with nitric acid, with an ICP mass spectrometer (trade name: PlasmaQuant MS Elite, manufactured by Analytik Jena). Specifically, 0.5 g of metallic tellurium was weighed accurately to 0.1 mg into an asking Teflon (registered trademark) vessel and moist-heated to melt at 240° C. for 10 minutes in 5 mL of 69% high-purity nitric acid with a microwave sample preparation system (trade name: START D, by Milestone General), thus completely dissolving metallic tellurium in nitric acid. The solution was fixed to a volume of 50 mL with ultrapure water and 1 mL of sample was taken from the solution, diluted 20-fold with ultrapure water, and measured in terms of copper content with an ICP mass spectrometer.

(4) The specific surface area of metallic tellurium was measured by the BET method with a surface area analyzer (trade name: TriStar II 3020, manufactured by Shimadzu Corporation).

(5) <Production of Organic Tellurium Compound>

Example 1

(6) Under a nitrogen atmosphere, 6.38 g (50 mmol) of metallic tellurium (oxygen content: 2%, copper content: 1 ppm) was suspended in 50 mL of tetrahydrofuran. An amount of 34.4 mL (55 mmol) of n-butyl lithium (1.6 M solution thereof in hexane) was added slowly (over 10 minutes) dropwise into the obtained suspension on ice (at 0° C.). The obtained reaction solution was stirred on ice (at 0° C.) until metallic tellurium completely disappeared (for 20 minutes). An amount of 10.7 g (55 mmol) of ethyl-2-methyl-2-bromo-propionate was added into the reaction solution on ice (at 0° C.) and the mixture was stirred on ice (at 0° C.) for 2 hours. After the end of the reaction, the reaction solution was returned to room temperature (23° C.), 20 mL of water and 15 mL of ethyl acetate were added to the reaction solution, the mixture liquid was stirred for 5 minutes, then allowed to stand still, and thus separated into two layers, and a water layer as a heavy liquid was withdrawn. Similar liquid separation by water washing was repeated twice and an ethyl acetate layer as a light liquid was concentrated in vacuum, thus obtaining 13.28 g of oily matter.

(7) When analyzed with .sup.1H-NMR (trade name: AVANCE 500, manufactured by Bruker Corporation), the oily matter was ethyl-2-methyl-2-n-butyltellanyl-propionate (hereinafter referred to as “BTEE”) (yield: 88%) and dibutyl telluride (Bu.sub.2Te) (yield: 4.0%). The results are shown in Table 1.

Examples 2 to 8

(8) The same operation as in Example 1 was performed except that metallic tellurium having exhibited an oxygen content and a copper content shown in Table 1 in the measurements with the X-ray fluorescence spectrometer and the ICP mass spectrometer was selected and used in place of metallic tellurium in Example 1, so that an oily matter was obtained. The results are shown in Table 1. The measurements with the X-ray fluorescence spectrometer and the ICP mass spectrometer were conducted in the same manners as in Example 1.

Comparative Examples 1 to 2

(9) The same operation as in Example 1 was performed except that metallic tellurium having exhibited an oxygen content and a copper content shown in Table 1 in the measurements with the X-ray fluorescence spectrometer and the ICP mass spectrometer was selected and used in place of metallic tellurium in Example 1, so that an oily matter was obtained. A slight amount of metallic tellurium remained in the reaction solution after dropwise addition of n-butyl lithium. The results are shown in Table 1. The measurements with the X-ray fluorescence spectrometer and the ICP mass spectrometer were conducted in the same manners as in Example 1.

(10) TABLE-US-00001 TABLE 1 Source Material Yields of (Metallic Tellurium) Reaction Products oxygen content copper content SSA BTEE Bu.sub.2Te (%) (ppm) (m.sup.2/g) (%) (%) Ex. 1 2 1 1.2 88 4.0 Ex. 2 2 3 1.2 92 2.2 Ex. 3 2 14 1.2 94 0.8 Ex. 4 2 17 1.2 94 0.8 Ex. 5 2 21 1.2 94 2.3 Ex. 6 2 36 1.2 92 2.9 Ex. 7 2 55 1.2 86 4.6 Ex. 8 2 83 1.2 87 5.1 Comp. 3 100 1.2 71 13.2 Ex. 1 Comp. 2 102 1.2 76 11.1 Ex. 2

(11) <Production of Vinyl Polymer>

(12) Using each of the organic tellurium compounds (oily matters) obtained in Examples 1 to 8, methyl acrylate was polymerized by living radical polymerization, thus obtaining vinyl polymers. It was visually confirmed that all the obtained vinyl polymers were not colored.

(13) Using each of the organic tellurium compounds obtained in Comparative Examples 1 to 2, methyl acrylate was polymerized by living radical polymerization, thus obtaining vinyl polymers. It was visually confirmed that all the obtained vinyl polymers were colored.