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Chemical Industry Standard of the People's Republic of China
HG2311—92
Ethephon Technical
Published on June 1, 1992
Ministry of Chemical Industry of the People's Republic of China
Implemented on January 1, 1993
Chemical Industry Standard of the People's Republic of China
Ethephon Technical
Subject Content and Scope of Application
HG2311—92
This standard specifies the technical requirements, test methods, inspection rules, and marking, packaging, transportation and storage requirements for ethephon technical. This standard applies to the synthesis of phosphite from ethylene oxide and phosphorus trichloride, molecular rearrangement at high temperature, and acid hydrolysis to obtain ethephon technical.
Active ingredient: ethephon
Chemical name: 2-chloroethylphosphonic acid
Structural formula:
CICH2CH2
Molecular formula: C2HCIOP
Relative molecular mass: 144.45 (according to the international relative atomic mass in 1989)2
Cited standards
GB1604
GB1605www.bzxz.net
GB3796
3 Technical requirements
Preparation of standard solution for titration analysis (volume analysis) of chemical reagents Rules for acceptance of pesticides
Sampling method for commercial pesticides
General rules for pesticide packaging
3.1 Appearance: colorless liquid to light brown liquid or white to light brown solid. 3.2
The technical material of ethephon shall meet the following index requirements: (m/m)
Ethephon content, %
Acidity (calculated as HC1), %
Water-insoluble matter, %
Test method
4.1 Determination of ethephon content
Approved as first-class product by the Ministry of Chemical Industry of the People's Republic of China on June 1, 1992
Qualified product
Implemented on January 1, 1993
4.1.1 Summary of method
HG2311-92
The solid sample is heated and dissolved, weighed, esterified with diazomethane, and separated and determined by gas chromatography using p-nitrochlorobenzene as internal standard solution, 10% SE-30/GasChromQ chromatographic column and hydrogen flame ionization detector. 4.1.2 Reagents and solutions
Saturated solution of diazomethane ether: see Appendix A for preparation; acetone (GB686): analytical grade;
Ethephon standard sample with known content;
p-Nitrochlorobenzene: internal standard;
Carrier: CasChromQ150~180um (80~100); Stationary phase: SE-30:
Chloroform (GB682): analytical grade.
4.1.3 Preparation of internal standard solution
Weigh 5g of p-nitrochlorobenzene and add it to a 100mL volumetric flask, dilute to the mark with acetone, and prepare a 50mg/mL internal standard solution. 4.1.4 Instruments
Gas chromatograph: with FID detector;
Chromatographic column: 2000mm×3mm (inner diameter) glass or stainless steel column, filled with 10% SE-30/GasChromQ150~180um (80～100 mesh).
4.1.5 Operation steps
4.1.5.1 Preparation of chromatographic column
a. Coating of stationary liquid
Weigh 1.00g SE-30 in a 100mL round-bottom flask, add 40mL chloroform to dissolve. Heat and reflux on a water bath for 2h to completely dissolve SE-30, slowly add 10g dry GasChromQ (150～180μum) through a clean glass funnel to soak the carrier in the solution. After leaving at room temperature, transfer all the SE-30 solution and the carrier to the evaporator. Slowly drive off the solvent under the infrared lamp in the fume hood, and turn the carrier three times with a steel spoon to make it evenly coated. Then move it to a 90-100℃ oven and bake it for 30 minutes. b. Filling of the chromatographic column
Connect a small funnel to the inlet of the cleaned and dried chromatographic column, fill the outlet with an appropriate amount of glass wool and wrap it with gauze, connect it to the vacuum pump through a rubber tube, then turn on the vacuum pump and slowly pour the filler from the funnel, and keep tapping the column wall to make the filler fill the chromatographic column evenly and tightly. Remove the chromatographic column, plug the glass wool at the inlet, and press it appropriately to keep the filler from moving. c. Aging of the chromatographic column
Connect the inlet of the chromatographic column to the vaporization chamber of the gas chromatograph, and do not connect the outlet to the detector. Raise the nitrogen flow rate of about 10mL/min in stages to 240℃, and age it at this temperature for 10h. After cooling, connect the outlet of the column to the detector. 4.1.5.2 Gas chromatography operating conditions
Temperature:
Column chamber 160℃;
Vaporization chamber 190℃;
Detector temperature 200℃;
Gas flow rate:
Carrier gas ((N,) 14mL/min;
Hydrogen (H2) 35mL/min;
Air 580mL/min;
Injection volume:
Retention time:
Peak 1 ethephon methyl ester about 4.4min;
Peak 2 internal standard about 6.4min.
Chromatogram (see Figure 1)
HG2311-92
Figure 1 Chromatogram after ethephon methylation
Analysis operating conditions can be adjusted according to different types of Make appropriate adjustments to the instrument to obtain the best results. 4.1.5.3 Preparation of standard solution
Weigh about 0.06g (accurate to 0.0001g) of standard sample containing ethephon and add it to a 50mL conical flask with a ground mouth. Add diazomethane ether solution in an ice bath until it turns yellow. Put the stopper on and shake it in an ice bath for 30 minutes until the yellow color does not disappear. Use nitrogen to blow away the ether and diazomethane in a 30℃ water bath, accurately add 2mL of internal standard solution, and shake well. 4.1.5.4 Preparation of test sample
Same as 4.1.5.3.
4.1.5.5 Determination
Inject several injections of standard solution according to the gas chromatography conditions in 4.1.5.2 until the peak area ratio of two adjacent injections changes by no more than 1.5%, and then inject in the following order. || tt||a. Standard solution;
Test solution;
c. Test solution;
d. Standard solution.
Use a 10uL microsyringe to inject 1uL each time with two injections of test sample and two injections of standard sample, so that the peak area ratio does not change by more than 1.5%, otherwise repeat the injection.
4.1.5.6 Calculation
Average the obtained peak area ratios of a, d and b, c respectively, and calculate the mass percentage content of ethephon r1 according to formula (1): a1
Wherein: -
The average value of the peak area ratio of ethephon methyl ester to the internal standard in the standard solution; The average value of the peak area ratio of ethephon methyl ester to the internal standard in the test solution; -The mass of the ethephon standard, g;
The mass of the ethephon test sample, name;
w —Mass percentage of ethephon standard sample, %4.1.5.7 Allowable difference
The difference between two parallel determination results should be less than 1.5%. 4.2 Determination of acidity
4.2.1 Reagents and solutions
Distilled water should meet the requirements of grade 3 water in GB6682: HG2311-92
Sodium hydroxide (GB629) standard titration solution: c(NaOH)=0.1mol/L, prepared according to GB601; phenol ethanol solution: 1g/L, prepared according to GB603. 4.2.2 Determination steps
Weigh 0.2g of the sample (accurate to 0.0001g) in a 100mL beaker, add 25mL of distilled water to dissolve the sample, and titrate with sodium hydroxide standard titration solution until the phenol changes color, which is the end point, and perform a blank test at the same time. 4.2.3 Calculate the mass percentage of
acidity (in terms of HCl) 2 according to formula (2): c(V,-V.)-
wherein·c-
actual concentration of standard sodium hydroxide titration solution, mol/L;X0.0365X100
the volume of standard sodium hydroxide titration solution consumed when measuring the sample, mL:V? --the volume of standard sodium hydroxide titration solution consumed when measuring the blank, mL:1-the mass percentage of ethephon, %;ms
the mass of ethephon sample, g;
the mass of hydrochloric acid equivalent to 1.00mL standard sodium hydroxide titration solution [c(NaOH)=1.000mol/L) expressed in grams;
the mass of ethephon equivalent to 1.00mL standard sodium hydroxide titration solution Cc(NaOH)=1.000mol/L) expressed in grams.
4.3 Determination of water-insoluble matter
4.3.1 Instruments
Weighing bottle;
G3 sand core crucible, average pore size 20-30um; oven, 150±2℃;
100mL Buchner suction flask and filter joint.
4.3.2 Determination steps
Wash and dry the G3 sand core crucible to constant weight, accurate to 0.0001g. Weigh 5g of sample (accurate to 0.0001g), add 50mL of distilled water to a 100mL beaker, shake vigorously, dissolve the soluble matter completely, and transfer all to the glass. Filter with a vacuum pump, wash the residue with distilled water, 25mL each time, wash 3 times in total, and drain. Bake the crucible and the residue in a 105℃ oven to constant weight (accurate to 0.0001g).
4.3.3 Calculation
The mass percentage of water-insoluble matter: Calculate as-
According to formula (3): m4-
-The mass of the sand core crucible after constant weight, 8;
The total mass of the crucible and water-insoluble matter after constant weight, ;-The mass of the sample, g.
5 Acceptance rules
5.1 The acceptance rules shall be in accordance with GB1604.
5.2 The sampling method shall be in accordance with GB1605.
6 Marking, packaging, transportation, storage
HG2311-92
6.1 The packaging marking of ethephon technical shall comply with the relevant provisions of GB3796 General Rules for Pesticide Packaging. The packaging shall have the standard number, trademark, production license (or production permit) number and pesticide registration number. The packaging shall be packed in plastic barrels, and the net weight of each piece shall not exceed 100kg. 6.2 During storage and transportation, it should be handled with care.
6.3 This product must not come into contact with alkaline substances, and cannot be mixed with other pesticides and fertilizers for stacking and use; it must be strictly protected from the sun and rain, and maintained with good ventilation; it must not be mixed with food, seeds, and feed, and avoid contact with the skin, prevent inhalation through the mouth and nose, and must comply with the provisions of GB190 Dangerous Goods Transport Regulations.
A12-Preparation of nitroso-2-methylurea
HG2311—92
Appendix A
Preparation of diazomethane
(Supplement)
In a weighed 250mL flask, add 13.5g of methylamine hydrochloride, then add 67g of water, then add 40.2g of urea, reflux slowly for 2h45min, then reflux vigorously for 15min, cool to room temperature, add 20.2g of sodium nitrite, and cool the entire solution to 0℃. Add 80g of ice to a 1L beaker and cool in an ice-salt bath, then add 13.3g of concentrated sulfuric acid, and add the freshly prepared methyl urea-nitrite while stirring so that the temperature does not exceed 0℃. The addition takes about 1h.
Nitrosomethylurea forms a crystalline foamy precipitate floating on the surface, which is immediately filtered by suction and pressed dry, then washed with a small amount of ice water. The resulting crystals are dried in a vacuum dryer at a temperature not exceeding 4°C. 2 Preparation of diazomethane
Put 60mL of 50% potassium hydroxide aqueous solution and 200mL of ether in a 500mL round-bottom flask, cool the mixture to 0°C, then add 20.62-nitroso-2-methylurea while shaking, and install a condenser on the flask for distillation. The lower end of the condenser is connected to a receiving tube, which is immersed in the 40mL ether liquid in a 250mL conical flask through a double-hole rubber stopper. The conical flask is placed in an ice-salt bath for cooling. The released gas is passed into the second 40mL ether that is also cooled to below 0℃. The reaction flask is placed in a 50℃ water bath to reach the boiling point of ether. It is shaken from time to time. The ether is evaporated until the distillate becomes colorless. Usually, the distillate becomes colorless after 2/3 of the acetaldehyde is evaporated. In any case, the ether cannot be evaporated to dryness. The ether solution in the receiver is combined, which contains 5.3-5.9g of diazomethane.
Additional remarks:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of the Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Element Institute of Nankai University, and Shanghai Pengpu Chemical Plant and Jiangsu Huaiyin Electrochemical Plant participated in the drafting. The main drafters of this standard are Zhu Changshou, Yan Bingwen, Chen Yong, Yang Zuoliang, Li Maoqing, Liang Qinying and Wang Qinsun.
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