Process for the reductive preparation of formate salts of organic phosphine compounds

Abstract

The application relates to the field of new organic phosphine functional material chemicals, and discloses a reaction technology for reducing organic phosphine halogen bond P-X into phosphine hydrogen bond P-H under the action of formic acid or formate. The process technology has the characteristics of outstanding production safety, low cost, economic competitiveness and environmental friendliness. The prepared organic phosphine compound is a key raw material for photo-curing initiators, phosphorus-containing monomers and resins, organic phosphine flame retardants, pesticides, medicines, electronic chemicals and the like.

Description

[Technical Field]

[0001] This invention relates to the field of organophosphorus functional new materials and chemicals, and for the first time discloses a reaction technology for reducing organophosphorus halogen bonds (PX) to phosphorus hydrogen bonds (PH) under the action of formic acid or formate. This process technology boasts outstanding production safety, low-cost economic competitiveness, and environmental friendliness. The resulting organophosphorus compounds are key raw materials for photocuring initiators, phosphorus-containing monomers and resins, as well as organophosphorus flame retardants, pesticides, pharmaceuticals, and electronic chemicals. [Background Technology]

[0002] Organophosphorus compounds are versatile functional chemicals that are of great industrial significance as raw materials, intermediates, or end-products in fields such as photocuring initiators, phosphorus-containing monomers and resins, as well as organophosphorus flame retardants, pesticides, pharmaceuticals, and electronic chemicals.

[0003] For example, in the photocuring initiator industry, some monofunctional or difunctional acylphosphine (oxy) compounds, such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide (trade name TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (trade name TPO-L), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (trade name 819), are well-known highly efficient photoinitiators for radiation-dependent polymerization systems containing olefinic unsaturated groups. In the functional monomer and resin industry, phosphorus-containing acrylates are excellent adhesion promoters. In the flame retardant field, organophosphine compounds are representative of emerging low-smoke, halogen-free products, such as diphenylphosphine oxide and DOPO. In the agrochemical field, numerous organophosphine compounds, represented by glyphosate and glufosinate, are highly efficient and low-toxicity leading commercial products.

[0004] The most inexpensive and readily available organophosphorus precursors in industry are typically substances containing phosphorus-halogen (PX) characteristic oxidation state chemical bonds (where X represents a halogen atom), such as phosphine trichloride PCl3, phosphorus tribromide PBr3, phenylphosphine dichloride PhPCl2, diphenylphosphine chloride Ph2PCl, and methylphosphine dichloride MePCl2. The reduction of these PX characteristic oxidation state chemical bonds, especially to the corresponding highly reactive PH bond substances, usually requires strong reducing agents, such as metals, metals and hydrogen, metal hydrides (e.g., lithium aluminum hydride, aluminum hydride), boranes, silanes, etc. The reducing agents involved are expensive, the conditions are harsh, and the process safety risks are significant (e.g., Chinese patent CN1211388).

[0005] Given the outstanding practical value of organophosphorus hydrogen compounds, the industry has been continuously exploring new preparation processes that are more cost-competitive and safe and environmentally friendly. [Summary of the Invention]

[0006] This application discloses for the first time a novel preparation process for a series of organophosphorus compounds with the structural formulas R1PH2 and R1R2PH, as shown in formulas (I-III). These processes are initiated from corresponding starting materials, phosphine halides R1PX2 and R1R2PX, either separately or simultaneously, and compounds with the structural formula [HCO2]. n The formate of Q is prepared by direct action under the following conditions: Where X is chlorine, fluorine, bromine, or iodine; Q is hydrogen, or an n-valent metallic or non-metallic cation; n takes the integer value between 1 and 6; Metal cations refer to the cation forms of metallic elements in the periodic table, while non-metal cations refer to the cation forms of ammonia, quaternary ammonium, or quaternary phosphine. R1 or R2 are independent of each other and contain 1-24 carbon atoms (denoted as C) with monovalent or divalent oxidation states. 1 -C 24 (hereinafter the same) straight-chain or branched alkyl or C 3 -C 12 Cycloalkyl or alkoxy; or monovalent or divalent C 4 -C 24 Substituted or unsubstituted aryl or heteroaryl or aryloxy groups; The conditions are at least one of solvent, temperature, pressure (or vacuum), and additives.

[0007] Preferably, X is chlorine; Preferred [HCO2] n The values ​​of Q are HCO2H, (HCO2H)5(NEt3)2, HCO2NH4, HCO2(NHR1R2R3), HCO2Na, HCO2K, HCO2Li, HCO2Cs, (HCO2)2Ca, (HCO2)3Al, (HCO2)2Zn, (HCO2)2Ba, (HCO2)2Mg, and (HCO2)3Fe; among which, the value of R3 is the same as that of R1. More preferably [HCO2] n The values ​​of Q are HCO2H, HCO2NH4, HCO2Na, HCO2K, HCO2Li, HCO2Cs, (HCO2)2Ca, (HCO2)2Mg, (HCO2)3Al, HCO2(HNEt3), HCO2(HNBu3), (HCO2H)5(NEt3)2, (HCO2H)2(Me2N-CH2CH2-NMe2)2; The solvent is selected from at least one of substituted or unsubstituted aromatic hydrocarbons containing 1-24 carbons, straight-chain or branched aliphatic hydrocarbons, (sulfoxide) sulfones, amides, ethers, esters, ketones, nitriles, carboxylic acids, water, amines, carbonates, ionic liquids, and supercritical carbon dioxide.

[0008] In some preferred embodiments of the present invention, the solvent is selected from at least one of dimethyl sulfoxide, dimethyl sulfone, benzyl sulfoxide, benzyl sulfone, cyclobutane sulfoxide, cyclobutane sulfone, trichlorosilane, dichloromethane, dichloroethane, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, chloroform, carbon tetrachloride, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetonitrile, ethylbenzene, diethylbenzene, chlorobenzene, dichlorobenzene, anisole, nitrobenzene, heptane, hexane, petroleum ether, dioxane, tetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, propylene glycol methyl ether acetate, triethylamine, tributylamine, dimethylisopropylamine, pyridine, N,N-tetramethylethylenediamine, N-alkylmorpholine, N-alkylpyrrole, N,N-dimethylformamide, formylmorpholine, N,N-diethylformamide, and N-methylpyrrolidone.

[0009] In this invention, the reaction may also be carried out by using only a small amount or even no conventional "solvent", but by solid-phase heating and / or grinding of the raw materials, and / or ultrasonic and / or microwave irradiation to promote the reaction.

[0010] The temperature is -70℃ to 300℃. Preferably, the temperature is -30℃ to 200℃.

[0011] The pressure is 0.001 atm-200 atm. Preferably, the pressure is 0.1 atm-100 atm.

[0012] The additives refer to reaction promoters, synergists, catalysts, oxidants, polymerization inhibitors, reducing agents and / or functional auxiliaries; based on the molar amount of the reaction raw materials, the amount of the additives used is the catalytic amount or equivalent amount or superequivalent amount (0-100 equivalents).

[0013] One preferred embodiment of reaction (I) is reaction (IV), consisting of phenylphosphine dichloride and formate [HCO2]. n Q is prepared by direct reduction reaction under the following conditions: One preferred embodiment of reaction (II) is reaction (V), which involves diphenylphosphine chloride and formate [HCO2]. n Q is prepared by direct reduction reaction under the following conditions: One preferred embodiment of reaction (III) is reaction (VI), consisting of a mixture of phenylphosphine dichloride and diphenylphosphine chloride, and formate [HCO2]. n Q involves a one-pot reduction reaction under the specified conditions to simultaneously prepare phenylphosphine and diphenylphosphine: As is known to those skilled in the art, alkylphosphine and acyl chloride can be readily prepared into corresponding acylphosphine alkylates under alkaline conditions. These intermediates can then be oxidized to generate so-called mono- or diacylphosphine oxides, which are well-known photoinitiator chemicals, particularly commercial products such as TPO, TPO-L, and 819.

[0014] It is particularly important to emphasize that, due to the fundamental differences in the principles of chemical conversion technologies, the previous method of directly reducing a mixture of phenylphosphine dichloride and diphenylphosphine chloride to phenylphosphine and diphenylphosphine in a "one-pot" manner was either too costly or impossible. Therefore, the method disclosed in this invention has significant industrial implications. As shown in reaction formula (VII), it is the first time that a "one-pot" method has been achieved to prepare monoacylphosphine oxide TPO and diacylphosphine oxide 819 from a mixture of phenylphosphine dichloride and diphenylphosphine chloride. This is an unprecedented technological breakthrough in the industry.

[0015] The conditions preferably include an alkaline accelerator, and the preferred alkaline accelerator is a tertiary amine or sodium tert-butoxide; [O] is an oxidizing agent, and the preferred oxidizing agent is hydrogen peroxide, oxygen, or peroxide.

[0016] We will explain further in the embodiments.

Detailed Implementation Methods

[0017] The essence of the invention is further illustrated below with reference to specific embodiments: Example: Under nitrogen protection and at room temperature, 68 mg of dry sodium formate was added to a flask, followed by 5 mL of freshly distilled anhydrous n-hexane and 0.22 g of diphenylphosphine chloride. The mixture was heated and stirred at 70°C for 8 hours. After cooling to room temperature, triphenylphosphine was added to the mother liquor under a nitrogen atmosphere as an internal standard for quantitative analysis. The phosphorus NMR spectrum was measured using a closed J-Young Tube, yielding diphenylphosphine in 84% yield.

[0018] 31 P-NMR (400 MHz, δ): -40.2 ppm.

[0019] Repeat the above experiment, except that anhydrous sodium formate (HCO2Na) was replaced with an equimolar amount of anhydrous ammonium formate (HCO2NH4), to obtain diphenylphosphine in 52% yield.

[0020] The above experiment was repeated, except that anhydrous sodium formate (HCO2Na) was replaced with an equimolar amount of commercially available (HCO2H)5(NEt3)2 adduct, to obtain diphenylphosphine in 28% yield.

[0021] Example: Under nitrogen protection and at room temperature, 136 mg of dry sodium formate was added to a flask, followed by 5 mL of freshly distilled anhydrous n-hexane and 0.18 g of phenylphosphine dichloride. The mixture was heated and stirred at 70°C for 8 hours. After cooling to room temperature, triphenylphosphine was added to the mother liquor under a nitrogen atmosphere as an internal standard for quantitative analysis. The phosphorus NMR spectrum was measured using a closed J-Young Tube, yielding phenylphosphine in 52% yield.

[0022] 31 P-NMR (400 MHz, δ): -124.2 ppm.

[0023] The above experiment was repeated, except that anhydrous sodium formate (HCO2Na) was replaced with an equimolar amount of commercially available (HCO2H)5(NEt3)2 adduct, to obtain phenylphosphine in 66% yield.

[0024] Example: Under nitrogen protection and at room temperature, 0.22 g of carefully dried sodium formate was added to a flask, followed by 12 mL of freshly distilled anhydrous n-hexane, and 0.4 g of diphenylphosphine chloride and phenylphosphine dichloride (1 mmol each). The mixture was heated and stirred at 70 °C for 10 hours. After cooling to room temperature, triphenylphosphine was added to the mother liquor under a nitrogen atmosphere as an internal standard for quantitative analysis. The phosphorus NMR spectrum was measured using a closed J-Young Tube, yielding diphenylphosphine in 86% yield and phenylphosphine in 54% yield.

[0025] Example: Under nitrogen protection and at room temperature, 16 mL of toluene solution containing 0.76 mmol of diphenylphosphine and 0.5 mmol of phenylphosphine was placed in a Schlenk flask, and 0.13 g of sodium tert-butoxide was added. 2 mL of toluene solution containing 0.34 g of mesityleneformyl chloride was added dropwise with repeated stirring. After the addition was complete, the reaction was stirred for 3 hours. The pH of the system was adjusted to approximately 3 with dilute sulfuric acid. 2.2 mmol of 30% hydrogen peroxide aqueous solution was added under light-protected conditions. After complete oxidation, the reaction solution was diluted with 30 mL of toluene. The organic phase was washed three times successively with semi-saturated brine and water. The organic phase was dried over anhydrous sodium sulfate, concentrated, and eluted by silica gel column chromatography to obtain 0.24 g of TPO and 0.18 g of 819, a pure pale yellow powder.

[0026] It should be emphasized that the above embodiments are merely exemplary and not limiting. Based on the disclosure of this application, any adjustments or changes to the reaction conditions or parameters that a person skilled in the art might normally adopt will not deviate from the spirit of the invention. The scope of protection of this patent shall be determined by the relevant claims.

Claims

1. A method for preparing organophosphorus compounds with structural formulas R1PH2 and R1R2PH, as shown in formulas (I-III), comprising, respectively, or simultaneously, starting materials of phosphine halides R1PX2 and R1R2PX, and [HCO2] n The formate of Q or HCO2H is directly prepared under the reaction conditions: ； Where X is one of chlorine, fluorine, bromine, and iodine; R1 or R2 are independent of each other and are monovalent C. 4 -C 24 Non-substituted aryl groups; The aforementioned [HCO2] n Q is HCO2NH4, HCO2(NHR1) ’ R2 ’ R3 ’ One of the following: (HCO2Na), (HCO2K), (HCO2Li), (HCO2Cs), (HCO2)2Ca, (HCO2)3Al, (HCO2)2Zn, (HCO2)2Ba, (HCO2)3Fe, wherein R1 ’ R2 ’ R3 ’ Independent of each other are monovalent compounds containing C 1 -C 24 Straight-chain or branched alkyl groups; The reaction conditions are at least one of the following: solvent, temperature, and pressure. The solvent is n-hexane; The temperature is 70 ℃-200 ℃; The pressure is 0.1 atm-100 atm.

2. The method according to claim 1, wherein one embodiment of formula (I) is reaction (IV), consisting of phenylphosphine dichloride and formate [HCO2]. n Q. Phenylphosphine is prepared by direct reduction reaction under the reaction conditions: 。 3. The method according to claim 1, wherein one embodiment of formula (II) is reaction (V), consisting of diphenylphosphine chloride and formate [HCO2]. n Q. Diphenylphosphine is prepared by direct reduction reaction under the reaction conditions: 。 4. The method according to claim 1, wherein one embodiment of formula (III) is reaction (VI), comprising a mixture of phenylphosphine dichloride and diphenylphosphine chloride and formate [HCO2]. n Q. A one-pot reduction reaction is carried out directly under the reaction conditions to simultaneously prepare phenylphosphine and diphenylphosphine: 。 5. The application of the phenylphosphine and diphenylphosphine prepared according to claim 1 or 4 in the preparation of photoinitiator 819 and TPO, wherein phenylphosphine and diphenylphosphine obtained by direct reduction of a mixture of phenylphosphine dichloride and diphenylphosphine chloride are condensed with mesitylene benzoyl chloride to prepare the corresponding di- and monofunctional acylphosphine alkyl groups, and then oxidized with an oxidizing agent to obtain photoinitiator 819 and TPO; wherein the reaction conditions include a base promoter, said base promoter being a tertiary amine or sodium tert-butoxide; [O] is an oxidizing agent, said oxidizing agent being one of hydrogen peroxide, oxygen, and peroxidizing acid: 。

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