Preparation method of sulfide heavy metal trapping agent C2H4N2S4

Abstract

The invention discloses a preparation method of sulfide heavy metal trapping agent C2H4N2S4. Cyclohexanol and acetone are prepared according to a certain volume ratio and used as a mixed solvent, carbon disulfide is dissolved in the mixed solvent to obtain a carbon disulfide mixed solution, the carbon disulfide mixed solution is slowly added in hydrazine hydrate in dropwise mode under stirring state according to a certain molar ratio, reaction is performed at a certain temperature, suction filtration is performed on reaction products, a filter cake is washed through absolute ethyl alcohol, and C2H4N2S4 can be obtained. The method selects cyclohexanol to replace ethylene glycol, can greatly reduce dosage of cyclohexanol in the mixed solvent, simultaneously improves product yield, and reduces production cost of C2H4N2S4.

Description

technical field

[0001] The invention relates to a preparation method of a sulfide heavy metal trapping agent, in particular to a preparation method of a sulfide heavy metal trapping agent tetrathiocarbamic acid. Background technique

[0002] Although my country's environmental protection has made positive progress, the severe environmental situation remains unchanged. The long-term accumulated environmental contradictions have not been resolved, especially the discharge of heavy metal pollutants exceeds the capacity of the environment, seriously endangering the health of the people. In recent years, the discharge of various heavy metal wastewater has caused serious pollution of soil and water, which has aroused widespread concern at home and abroad.

[0003] The traditional pH adjustment precipitation method treats wastewater containing heavy metal ions, that is, by adding alkaline chemicals such as sodium hydroxide, sodium carbonate, and lime, the wastewater is adjusted to...

Examples

Embodiment 1

[0029] A preparation method of sulfide heavy metal trapping agent tetrathiocarbamic acid, as follows:

[0030] At 32°C, dissolve 30 mL of carbon disulfide in a mixed solvent of 5 mL of cyclohexanol and 5 mL of acetone, and slowly add dropwise to a three-necked flask of 34 mL of 80% (wt%) hydrazine hydrate (density 1.019 g / mL) , stirred and reacted for 2.5 h, the reaction product was suction-filtered, and the filter cake was washed with absolute ethanol to obtain tetrathiohydrazine, a heavy metal chelating and trapping agent, with a conversion rate of carbon disulfide of 85.48%.

[0031] The infrared IR and nuclear magnetic NMR characterization results of the prepared product are as follows:

[0032] IR(KBr disk, cm -1 ): 3315 s(ν-N-H), 3377 w (ν-S-H), 1088 m (ν-N-C=S), 1122 and 1347 ss (ν-C=S), 1515 ss (δ–N-N-), 1450 m (νC-N), 958 m (νC-S).

[0033] 1 H NMR (D 2 O, 500 MHz) δ(ppm): 1.87 (SH, 2H), 2.15 (-NH, 2H).

Embodiment 2

[0035] In this example, tetrathiocarbamic acid was prepared in the same manner as in Example 1, except that the ratio of raw materials and process parameters were changed. See Table 1 for details of process conditions and results.

Embodiment 3

[0037] In this example, tetrathiocarbamic acid was prepared in the same manner as in Example 1, except that the ratio of raw materials and process parameters were changed. See Table 1 for details of process conditions and results.

[0038] Table 1

[0039] Process parameters Example 1 Example 2 Example 3 Carbon disulfide / mL 30 30 30 Hydrazine hydrate / mL 34 31 29 Cyclohexanol / mL 5 3.4 10 Acetone / mL 5 16.6 5 Mixed solvent / mL 10 20 15 Reaction temperature / ℃ 32 30 35 Reaction time / h 2.5 2 3 Carbon disulfide conversion % 85.48 92.96 87.51

technical field

[0001] The invention relates to a preparation method of a sulfide heavy metal trapping agent, in particular to a preparation method of a sulfide heavy metal trapping agent tetrathiocarbamic acid. Background technique

[0002] Although my country's environmental protection has made positive progress, the severe environmental situation remains unchanged. The long-term accumulated environmental contradictions have not been resolved, especially the discharge of heavy metal pollutants exceeds the capacity of the environment, seriously endangering the health of the people. In recent years, the discharge of various heavy metal wastewater has caused serious pollution of soil and water, which has aroused widespread concern at home and abroad.

[0003] The traditional pH adjustment precipitation method treats wastewater containing heavy metal ions, that is, by adding alkaline chemicals such as sodium hydroxide, sodium carbonate, and lime, the wastewater is adjusted to...

Examples

Embodiment 1

[0029] A preparation method of sulfide heavy metal trapping agent tetrathiocarbamic acid, as follows:

[0030] At 32°C, dissolve 30 mL of carbon disulfide in a mixed solvent of 5 mL of cyclohexanol and 5 mL of acetone, and slowly add dropwise to a three-necked flask of 34 mL of 80% (wt%) hydrazine hydrate (density 1.019 g / mL) , stirred and reacted for 2.5 h, the reaction product was suction-filtered, and the filter cake was washed with absolute ethanol to obtain tetrathiohydrazine, a heavy metal chelating and trapping agent, with a conversion rate of carbon disulfide of 85.48%.

[0031] The infrared IR and nuclear magnetic NMR characterization results of the prepared product are as follows:

[0032] IR(KBr disk, cm -1 ): 3315 s(ν-N-H), 3377 w (ν-S-H), 1088 m (ν-N-C=S), 1122 and 1347 ss (ν-C=S), 1515 ss (δ–N-N-), 1450 m (νC-N), 958 m (νC-S).

[0033] 1 H NMR (D 2 O, 500 MHz) δ(ppm): 1.87 (SH, 2H), 2.15 (-NH, 2H).

Embodiment 2

[0035] In this example, tetrathiocarbamic acid was prepared in the same manner as in Example 1, except that the ratio of raw materials and process parameters were changed. See Table 1 for details of process conditions and results.

Embodiment 3

[0037] In this example, tetrathiocarbamic acid was prepared in the same manner as in Example 1, except that the ratio of raw materials and process parameters were changed. See Table 1 for details of process conditions and results.

[0038] Table 1

[0039] Process parameters Example 1 Example 2 Example 3 Carbon disulfide / mL 30 30 30 Hydrazine hydrate / mL 34 31 29 Cyclohexanol / mL 5 3.4 10 Acetone / mL 5 16.6 5 Mixed solvent / mL 10 20 15 Reaction temperature / ℃ 32 30 35 Reaction time / h 2.5 2 3 Carbon disulfide conversion % 85.48 92.96 87.51

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