Preparation method for chromatographic grade N,N-dimethyl formamide

A dimethylformamide, chromatographic-grade technology, applied in the separation/purification of carboxylic acid amides, organic chemistry, etc., can solve the problem of high ultraviolet absorbance, and achieve the effects of high product purity, separation of impurities, and significant economic benefits.

Active Publication Date: 2012-06-27
天津市康科德科技有限公司
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Problems solved by technology

Due to the high ultraviolet absorbance, it cannot meet the needs of relevant scientific research experiments. Therefore, this kind of N,N-dimethylformamide must be further prepared to make its various technical indicators reach the indicators of high-purity chromatographic grade before it can be used.

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  • Preparation method for chromatographic grade N,N-dimethyl formamide

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Embodiment 1

[0020] A preparation method of chromatographic grade N, N-dimethylformamide, the steps are as follows:

[0021] (1) The raw material N,N-dimethylformamide (content is about 99.5%) is passed through a calcium hydride adsorption column with a particle size of 5mm to 10mm, the column volume is 4 / 5 of the column length, and the flow rate is about 50mL / min, N, N-dimethylformamide raw material is in full contact with calcium hydride, absorbs impurities such as moisture in it, and waits for the adsorption effluent to pass the inspection (that is, the indicators of the effluent are close to the technical index requirements of the chromatographic level, and the specific technical index requirements See table 1.) and enter the next step operation;

[0022] (2) Put the adsorption liquid in step (1) into a still, add 5% aluminum oxide (weight ratio) in the still, and pre-fire at 500-600° C. for about 1 hour. Distill under reduced pressure at a pressure of 5-10mmHg to further dehydrate a...

Embodiment 2

[0025] A preparation method of chromatographic grade N, N-dimethylformamide, the steps are as follows:

[0026] (1) The raw material N,N-dimethylformamide (content is about 99.5%) is passed through a calcium hydride adsorption column with a particle size of 10 mm to 15 mm. The amount of calcium hydride packed into the column is 4 / 5 of the column length, and the flow rate is about 140mL / min, N,N-dimethylformamide raw material is fully contacted with calcium hydride, absorbs impurities such as moisture in it, and waits for the adsorption effluent to pass the inspection (that is, the indicators of the effluent are close to the technical indicators of the chromatographic level, and the specific technology The index requirements are shown in Table 1.) and enter the next step;

[0027] (2) Pour the above-mentioned adsorption effluent into a still, add about 20% alumina (weight ratio) in the still, pre-burn at 500-600°C for about 2 hours, and distill under reduced pressure under a pr...

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Abstract

The present invention relates to a preparation method for chromatographic grade N,N-dimethyl formamide. The method comprises the following steps that: (1) a raw material N,N-dimethyl formamide flows through a calcium hydroxide adsorption column; (2) the N,N-dimethyl formamide after the adsorption and alumina are subjected to vacuum distillation, wherein the distillation is performed under a condition of 5-10 mmHg; (3) the distilled liquid is filtered by using a 0.45 mum microporous filtration membrane, and is subjected to bottling and storing through nitrogen filling to obtain the chromatographic grade N,N-dimethyl formamide. According to the present invention, the N,N-dimethyl formamide with the content of about 99.5% is adopted as the raw material, the calcium hydride column is adopted to adsorb the water and other impurities in the N,N-dimethyl formamide, the alumina is adopted to presinter to the temperature of 500-600 DEG C, and the vacuum distillation treatment is performed, such that the N,N-dimethyl formamide product with the purity more than 99.9% is prepared through the treatments of adsorbing, drying, and vacuum distillation, and the product can meet the chromatographic grade (HPLC) N,N-dimethyl formamide application requirements of the user.

Description

Technical field: [0001] The invention belongs to the technical field of chemical industry and relates to a preparation method of an organic solvent, in particular to a preparation method of chromatographic grade N,N-dimethylformamide. Background technique: [0002] N, N-dimethylformamide is the most widely used amide solvent, such as reagents for non-aqueous titration, solvents for vinyl resin and acetylene; organic synthesis, photometry, gas chromatography stationary liquid; separation and analysis of C2-C5 hydrocarbons; Separation of normal and isobutene-[1] and cis and trans-butene-[2]; analysis of pesticide residues; organic synthesis, etc. However, the content of commercially available N,N-dimethylformamide reagents is only about 99.5%, and the main impurities are water, trace amounts of ethanol, primary amines, secondary amines and other impurities. Because the ultraviolet absorbance is high, it cannot meet the needs of relevant scientific research experiments. Theref...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/03C07C231/24
Inventor 宋金链张玉芝
Owner 天津市康科德科技有限公司
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