CN113387981B

CN113387981B - Synthesis method of diethyl phosphite

Info

Publication number: CN113387981B
Application number: CN202110691280.5A
Authority: CN
Inventors: 费存; 姜长新
Original assignee: Liaoning Dopp Agriculture And Chemistry Co ltd
Current assignee: Liaoning Dopp Agriculture And Chemistry Co ltd
Priority date: 2021-06-22
Filing date: 2021-06-22
Publication date: 2022-12-02
Anticipated expiration: 2041-06-22
Also published as: CN113387981A

Abstract

The invention relates to a method for synthesizing diethyl phosphite, which comprises the steps of loading triethyl phosphite into a stirring reactor, heating to 70-80 ℃ within 30-60 minutes, adding water into the stirring reactor under the stirring condition, heating and reacting, wherein the molar ratio of the triethyl phosphite to the water is 1. The method is prepared by directly reacting triethyl phosphite with water, does not need a solvent or a catalyst compared with the traditional process, and has mild reaction and higher yield which can reach more than or equal to 99 percent; the raw materials are easy to obtain, and the production cost can be effectively reduced. The method has the advantages of simple operation, no side reaction in the reaction process, good product purity which can reach more than 99 percent, low cost, safety, environmental protection and suitability for industrial production.

Description

Synthesis method of diethyl phosphite

Technical Field

The invention belongs to the field of organic synthesis of fine chemical intermediates, and particularly relates to a synthesis method of diethyl phosphite.

Background

Diethyl phosphite is an important organic synthesis intermediate, and can be used as an intermediate to prepare a flame retardant plasticizer; also can prepare organophosphorus insecticide and acaricide; can also be used for preparing phosphate with special requirements and preparing metal corrosion inhibitor.

So far, two methods for preparing diethyl phosphite are mainly available, namely a direct esterification method of phosphorous acid and ethanol, a method for synthesizing diethyl phosphite by reacting phosphorous trichloride and absolute ethanol, wherein the first method has low esterification yield, is restricted by various factors and is not suitable for industrialization, and the second method needs a large amount of solvent or synthesizes a target product under an acidic condition, but the method is used for large-scale industrial production, but the method is used for raw material PCl ₃ The purity requirement is high, otherwise, potential safety hazards can be caused; in addition, side reactions can occur in the production process, and a large amount of byproduct hydrochloric acid is generated, so after the synthesis is completed, desorption and distillation are needed, incomplete treatment can directly lead to the over-standard acid value of the product, the yield of the product is influenced, the operation is difficult, and the production cost is increased.

Disclosure of Invention

The invention aims to provide a novel synthesis method of diethyl phosphite, which utilizes triethyl phosphite and water to synthesize diethyl phosphite under the conditions of low temperature and no solvent, and has the advantages of easily obtained raw materials, simple operation, low cost, safety, environmental protection, high yield and the like, and the byproduct ethanol can be reused for preparing the raw material triethyl phosphite.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a novel synthesis method of diethyl phosphite comprises the following specific steps:

putting triethyl phosphite into a stirring reactor, heating to 70-80 ℃ within 30-60 minutes, adding water into the stirring reactor under the stirring condition, heating and reacting, wherein the molar ratio of the triethyl phosphite to the water is 1, keeping the temperature for 60 minutes after the water is added, carrying out chromatographic analysis, controlling the triethyl phosphite to be less than or equal to 0.3%, starting a receiving bottle, carrying out reduced pressure rectification, distilling to remove low-boiling-point ethanol, stopping rectification, and pressurizing a reaction bottle to normal pressure by using nitrogen to obtain diethyl phosphite.

In a preferred embodiment, the temperature is gradually increased and the reaction is carried out at a rate of 4.0 ℃ per hour.

In a preferred scheme, the water can be added in a dropwise manner or in a one-time manner.

In the preferred scheme, when water is added dropwise, the water is added dropwise at a constant speed for 60 minutes.

In a preferred scheme, the vacuum degree is 0.095MPa when the vacuum rectification is carried out.

In a preferred embodiment, the triethyl phosphite has a purity of 99.5%.

In a preferred embodiment, the water is distilled water, purified water or softened water.

The reaction process of the invention comprises the following steps: (CH) ₃ CH ₂ O) ₃ P+H ₂ O＝(CH ₃ CH ₂ O) ₂ POH+CH ₃ CH ₂ OH。

Compared with the prior art, the invention has the following beneficial effects:

1. the method is prepared by directly reacting triethyl phosphite with water, does not need a solvent or a catalyst compared with the traditional process, and has the advantages of mild reaction, high yield which can be more than or equal to 99 percent;

2. because the raw materials triethyl phosphite and water are easy to obtain, the production cost can be effectively reduced.

3. The method has the advantages of simple operation, no side reaction in the reaction process, good product purity which can reach more than 99 percent, low cost, safety, environmental protection and suitability for industrial production.

Drawings

FIG. 1 is a gas chromatogram of diethyl phosphite synthesized in example 1 of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described in the following combined with the specific embodiments.

Triethyl phosphite with a purity of 99.5% and demineralized water were uniformly used as starting materials in the examples according to the invention and in the comparative examples.

Example 1

In this example, as shown in Table 1, 170g (1 mol) of triethyl phosphite was charged into a reaction flask, heated to 70 to 80 ℃ and 18g (1 mol) of water was added dropwise to conduct hydrolysis reaction. Controlling the dropping speed to be about 1 hour, preserving the heat for 1 hour after the dropping is finished, analyzing, and performing reduced pressure rectification on the residual 0.24 percent of the raw material. The vacuum degree was 0.095MPa, when the temperature of the contents in the flask reached 118 deg.C, the distillation was stopped, and the reaction flask was pressurized to normal pressure with nitrogen. 139.4g of 99.52% diethyl phosphite were obtained after completion of the reaction and recovery of the product, with a yield of 99.3%. The residual mother liquor in the bottle is the product except trace impurities. The residual mother liquor in the bottle is the product except trace impurities. The gas chromatogram of diethyl phosphite is shown in FIG. 1.

The test data are as follows:

through a plurality of batches of experiments, the optimal reaction conditions are finally obtained as follows: the proportion of the phosphorous acid to the water is 1mol, the reaction temperature is 70-80 ℃, and the dropping time is 1 hour.

Example 2

In this example, the raw materials were charged into a reaction flask at one time, and the rest of the charge amount, the raw material ratio, and the like were carried out in accordance with the general procedure of example 1. The actual yield of diethyl phosphite was 99.1% with a purity of 99.11%.

Example 3

The conditions of example 2 were otherwise carried out without removing the distillation residue of example 1 from the reaction flask before the triethyl neophosphite and water were charged into the reaction flask. The actual yield of diethyl phosphite was 99.2% with a purity of 99.21%.

Comparative example 1

The procedure of 2 was followed except that the distillation residue was not separated from the product, and the actual yield was 99.3% and the purity was 99.22%.

By the method, repeated recycling experiments are carried out, and the accumulation influence of the distillation residual liquid containing trace impurities recycled to the product can be ignored.

The content of the product is as follows: using gas chromatography area normalization

Acid value of the product: the sample is firstly dissolved by ethanol, methyl red is used as an indicator, and sodium hydroxide standard solution is used for titration.

Analysis shows that the diethyl phosphite obtained by the method provided by the invention has the content of over 99 percent and the acid value lower than 0.1mg/g, and all the contents meet the requirements of industrial products.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A synthesis method of diethyl phosphite comprises the following specific steps:

putting triethyl phosphite into a stirring reactor, heating to 70-80 ℃ within 30-60 minutes, dropwise adding water at a constant speed for 60 minutes under the stirring condition, adding the water into the stirring reactor dropwise, heating and reacting, wherein the heating speed is 4.0 ℃/h, the molar ratio of the triethyl phosphite to the water is 1, after the water is added, carrying out heat preservation for 60 minutes for chromatographic analysis, controlling the concentration of the triethyl phosphite to be less than or equal to 0.3%, starting a receiving bottle, carrying out reduced pressure rectification at the vacuum degree of 0.095Mpa to remove low-boiling-point ethanol, stopping rectification, and pressurizing a reaction bottle to normal pressure by using nitrogen to obtain the diethyl phosphite.

2. The method for synthesizing diethyl phosphite of claim 1, wherein: the purity of the triethyl phosphite is 99.5%.

3. The method for synthesizing diethyl phosphite according to claim 1, wherein the method comprises the following steps: the water is distilled water, purified water or softened water.