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Preparation technology of diazomethane

A preparation process, diazomethane technology, applied in the preparation of organic compounds, preparation of urea derivatives, organic chemistry, etc., can solve the problem of high cost of diazomethane equipment, and achieve the effect of low cost

Active Publication Date: 2019-08-02
ASYMCHEM LAB TIANJIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] The main purpose of the present invention is to provide a kind of preparation technology of diazomethane, to solve the problem of high equipment cost of preparing diazomethane in the continuous process in the prior art

Method used

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  • Preparation technology of diazomethane
  • Preparation technology of diazomethane

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preparation example Construction

[0031] The preparation process of the present application does not use expensive water removal membranes or equipment, and can obtain a diazomethane solution with extremely low water content at a relatively low cost, which can directly react with water-sensitive materials or systems;

[0032] Using low-cost, non-toxic N-methylurea as the starting material, the MNU obtained by continuous preparation can be directly prepared in the second step of continuous diazomethane without separation and purification, reducing the exposure to carcinogenic and allergenic materials MNU risk, and compared with most reactions using Diazald as the diazomethane precursor, the cost is lower and the three wastes are less;

[0033] The unique properties of continuous equipment (small reaction system and much higher heat exchange rate than batch equipment) make the reaction conditions more severe, but the safety is higher than that of batch reactions;

[0034] The unique properties of the continuous ...

Embodiment 1

[0047] Configure the feeding system A: Add 100g of N-methylurea to the feeding bottle A, add 100ml of water, slowly add 266g of 37% hydrochloric acid, and stir until dissolved.

[0048] Configure feeding system B: Add 1750mL 2-Me-THF into feeding bottle B.

[0049] Configure feeding system C: Add 140g of sodium nitrite to feeding bottle C, add 400ml of water, and stir until dissolved.

[0050] Configure feeding system D: Add 600mL 2-Me-THF into feeding bottle D.

[0051] Configure the mixing system E: Add potassium bicarbonate to the mixing bottle E, add 654ml of water, and stir until dissolved.

[0052] Equipment preparation: Add about 500ml of tap water to the first extraction column to half the column height; add about 200ml potassium bicarbonate aqueous solution to the second extraction column to 1 / 4 of the column height.

[0053] Fill the 200ml first PTFE coil reactor with tap water to 23-27°C (target temperature 25°C), after the temperature has stabilized for 10 minute...

Embodiment 2

[0065] The difference from Example 1 is that during the process of liquid separation and water removal, the upper yellow organic phase overflowed into a CSTR at -50°C and stirred for 40 minutes to freeze and remove water. The water solidified into ice at a low temperature to separate from the system. The organic solution of methane overflows through the overflow port with filter screen.

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Abstract

The invention provides a preparation technology of diazomethane. The preparation technology comprises the following steps: S1, with N-methylurea as a raw material, continuously preparing an N-methyl-N-nitrosourea-containing first product system in a continuous reactor; S2, extracting and reversely extracting the first product system continuously to obtain an N-methyl-N-nitrosourea solution; S3, performing a continuous reaction on the N-methyl-N-nitrosourea solution and an alkali solution in the continuous reactor to obtain a diazomethane-containing second product system; S4, performing continuous skimming and freezing water removal on the second product system to obtain the diazomethane. The N-methylurea is used as the raw material, a 2-methyltetrahydrofuran solution of MNU is obtained through a completely continuous reaction and posttreatment, and then an anhydrous diazomethane solution is directly obtained through a completely continuous reaction and posttreatment; through water removal by a freezing technology, use of an expensive semipermeable membrane or liquid-liquid separator is avoided, so that the cost is lower.

Description

technical field [0001] The invention relates to the field of diazomethane preparation, in particular to a preparation process of diazomethane. Background technique [0002] Diazomethane is a yellow gas with a strong pungent smell, soluble in ethanol and ether, and will explode when heated, met with fire, rubbed or hit. It is very active and can undergo various types of reactions. It is an important reagent in organic synthesis. It is mainly used for the methylation reaction of carboxyl groups, phenolic hydroxyl groups, enols, etc., and for the homologous of ketones and carboxylic acids in the preparation of diazoketones. Chemical reactions, 1,3 dipolar cycloaddition reactions, etc. Also, because of its low molecular weight, the reaction involving diazomethane is atomically efficient and nitrogen is the only by-product after the reaction. [0003] However, due to its strong carcinogenicity, toxicity and high explosive potential, the preparation and control of diazomethane i...

Claims

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Application Information

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IPC IPC(8): C07C245/16
CPCC07C245/16C07C273/18C07C275/68
Inventor 洪浩卢江平张恩选申慰闫红磊张震
Owner ASYMCHEM LAB TIANJIN
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