Preparation method of fluoroacetic acid for forensic science quantitative and qualitative use

Abstract

The invention discloses a preparation method of fluoroacetic acid for forensic science quantitative and qualitative use. The preparation method comprises the following steps of (I) preparing crude sodium fluoroacetate; (II) preparing the fluoroacetic acid. According to the preparation method of the fluoroacetic acid for forensic science quantitative and qualitative use provided by the invention, the yield is high, and the prepared fluoroacetic acid has high purity, can be directly used as a standard substance or a reference substance, and meets the requirement on forensic science poison analysis in real life.

Description

technical field

[0001] The invention relates to the field of forensic toxicology analysis. More specifically, it relates to a method for preparing fluoroacetic acid used in the field of forensic toxicology analysis. Background technique

[0002] Due to the great toxicity of fluoroacetic acid, it was banned by the relevant departments in 2003; however, due to its obvious effect in killing rodents in agricultural production, it is still sold in the market, especially on the stalls in the rural market, resulting in homicides and suicides Cases remain. In order to accurately identify whether the poison exists in the body, it is necessary to use standard or reference substances for qualitative and quantitative detection; however, the standard substances of the above two substances cannot be purchased from the market. For inspection and identification, it is urgent to synthesize and prepare sodium fluoroacetate and fluoroacetic acid used in the field of forensic toxicology analy...

Examples

Embodiment 1

[0029] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the steps of: (1) preparing crude sodium fluoroacetate;

[0030] (1-1) Dissolve 141 mmol, 13.6 mL of ethyl fluoroacetate or methyl fluoroacetate in 240 mL of ethanol;

[0031] (1-2) Add 155mmol and 6.2g of NaOH, and stir at 50°C for 12 hours to form a white precipitate;

[0032] (1-3) Remove the solvent under reduced pressure to dryness to obtain crude sodium fluoroacetate solid, wash the obtained crude sodium fluoroacetate solid with 30 mL of methyl tert-butyl ether three times, remove organic impurities and unreacted raw materials, and dry;

[0033] (II) preparing fluoroacetic acid;

[0034] (2-1) adding crude sodium fluoroacetate to hydrochloric acid with an HCl concentration of 3 mol / L, adjusting the pH value of the solution to 4, and adding NaCl to saturation;

[0035] (2-2) were extracted 4 times with 100mL methyl tert-butyl ether, and the organic layer ...

Embodiment 2

[0038] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the following steps:

[0039] (1) preparing crude sodium fluoroacetate;

[0040] (1-1) Dissolve 13.6mL (141mmol) of ethyl fluoroacetate or methyl fluoroacetate in 200mL of methanol;

[0041] (1-2) Add 6.72g (168mmol) of NaOH, stir at room temperature for 20 hours, and slowly form a white precipitate;

[0042] (1-3) Then the solvent was removed under reduced pressure to dryness to obtain crude sodium fluoroacetate, and the obtained crude sodium fluoroacetate solid was washed three times with 30 mL of methyl tert-butyl ether to remove organic impurities and unreacted raw materials, and dried.

[0043] (II) preparing fluoroacetic acid;

[0044] (2-1) Dissolving the crude sodium fluoroacetate in hydrochloric acid with an HCl concentration of 3mol / L, and adding NaCl to saturation;

[0045] (2-2) Then extract 4 times with 100mL methyl tert-butyl ether respectively,...

Embodiment 3

[0048] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the following steps:

[0049] (1) preparing crude sodium fluoroacetate;

[0050] (1-1) Dissolve 13.6 mL (141 mmol) of ethyl fluoroacetate or methyl fluoroacetate in 200 mL of a mixed solution of isopropanol and n-butanol, the volume ratio of isopropanol and n-butanol is 1:1;

[0051] (1-2) Add 6.72g (168mmol) of NaOH, stir at room temperature for 20 hours, and slowly form a white precipitate;

[0052] (1-3) Then, the solvent was removed under reduced pressure to dryness to obtain crude sodium fluoroacetate, and the obtained crude sodium fluoroacetate solid was washed three times with 30 mL of methyl tert-butyl ether to remove organic impurities and unreacted raw materials, and dried.

[0053] (II) preparing fluoroacetic acid;

[0054] (2-1) Dissolving the crude sodium fluoroacetate in hydrochloric acid with an HCl concentration of 3mol / L, and adding NaCl to sa...

technical field

[0001] The invention relates to the field of forensic toxicology analysis. More specifically, it relates to a method for preparing fluoroacetic acid used in the field of forensic toxicology analysis. Background technique

[0002] Due to the great toxicity of fluoroacetic acid, it was banned by the relevant departments in 2003; however, due to its obvious effect in killing rodents in agricultural production, it is still sold in the market, especially on the stalls in the rural market, resulting in homicides and suicides Cases remain. In order to accurately identify whether the poison exists in the body, it is necessary to use standard or reference substances for qualitative and quantitative detection; however, the standard substances of the above two substances cannot be purchased from the market. For inspection and identification, it is urgent to synthesize and prepare sodium fluoroacetate and fluoroacetic acid used in the field of forensic toxicology analy...

Examples

Embodiment 1

[0029] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the steps of: (1) preparing crude sodium fluoroacetate;

[0030] (1-1) Dissolve 141 mmol, 13.6 mL of ethyl fluoroacetate or methyl fluoroacetate in 240 mL of ethanol;

[0031] (1-2) Add 155mmol and 6.2g of NaOH, and stir at 50°C for 12 hours to form a white precipitate;

[0032] (1-3) Remove the solvent under reduced pressure to dryness to obtain crude sodium fluoroacetate solid, wash the obtained crude sodium fluoroacetate solid with 30 mL of methyl tert-butyl ether three times, remove organic impurities and unreacted raw materials, and dry;

[0033] (II) preparing fluoroacetic acid;

[0034] (2-1) adding crude sodium fluoroacetate to hydrochloric acid with an HCl concentration of 3 mol / L, adjusting the pH value of the solution to 4, and adding NaCl to saturation;

[0035] (2-2) were extracted 4 times with 100mL methyl tert-butyl ether, and the organic layer ...

Embodiment 2

[0038] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the following steps:

[0039] (1) preparing crude sodium fluoroacetate;

[0040] (1-1) Dissolve 13.6mL (141mmol) of ethyl fluoroacetate or methyl fluoroacetate in 200mL of methanol;

[0041] (1-2) Add 6.72g (168mmol) of NaOH, stir at room temperature for 20 hours, and slowly form a white precipitate;

[0042] (1-3) Then the solvent was removed under reduced pressure to dryness to obtain crude sodium fluoroacetate, and the obtained crude sodium fluoroacetate solid was washed three times with 30 mL of methyl tert-butyl ether to remove organic impurities and unreacted raw materials, and dried.

[0043] (II) preparing fluoroacetic acid;

[0044] (2-1) Dissolving the crude sodium fluoroacetate in hydrochloric acid with an HCl concentration of 3mol / L, and adding NaCl to saturation;

[0045] (2-2) Then extract 4 times with 100mL methyl tert-butyl ether respectively,...

Embodiment 3

[0048] A method for preparing fluoroacetic acid for qualitative and quantitative use in forensic science, comprising the following steps:

[0049] (1) preparing crude sodium fluoroacetate;

[0050] (1-1) Dissolve 13.6 mL (141 mmol) of ethyl fluoroacetate or methyl fluoroacetate in 200 mL of a mixed solution of isopropanol and n-butanol, the volume ratio of isopropanol and n-butanol is 1:1;

[0051] (1-2) Add 6.72g (168mmol) of NaOH, stir at room temperature for 20 hours, and slowly form a white precipitate;

[0052] (1-3) Then, the solvent was removed under reduced pressure to dryness to obtain crude sodium fluoroacetate, and the obtained crude sodium fluoroacetate solid was washed three times with 30 mL of methyl tert-butyl ether to remove organic impurities and unreacted raw materials, and dried.

[0053] (II) preparing fluoroacetic acid;

[0054] (2-1) Dissolving the crude sodium fluoroacetate in hydrochloric acid with an HCl concentration of 3mol / L, and adding NaCl to sa...