Some standard content:
National Standard of the People's Republic of China
Fluoromethane
Trlchioromethane for industrial use1Subject content and scope of application
GB 4118-92
Replaces GB411883
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, storage and transportation of industrial chloroform. This standard applies to chloroform produced by methane chlorination method, acetaldehyde method, triacetaldehyde alkaline hydrolysis method and photochlorination method. This product is mainly used as raw material for monochloromonochloromethane, solvent, pharmaceutical and synthetic fragrance. Formula: CHCI
Relative molecular mass 119.378 (according to the 1987 international relative atomic mass) 2 Reference standards
Packaging, storage and transportation pictorial symbols
GB 191
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB 601
GB3143
Determination of color of liquid chemical products (Hazen unit - platinum-cobalt color number) Determination of acidity in industrial liquid chloromethane products Titration method GB4120.3
GB 4120.5
Determination of micro-basic water content in industrial liquid chloromethane products Single point method Packaging, marking, storage, transportation and inspection rules for industrial liquid chloromethane products GB 4120. 6
Determination of water content in chemical products Karl Fischer method (general method) GB6283
GB 6678
GB 6680wwW.bzxz.Net
3 Technical requirements
General rules for sampling of chemical products
General rules for sampling of liquid chemical products
Liquids with clear appearance, no suspended matter, and no mechanical impurities. 3.1
3.2·The technical indicators of industrial trichloromethane shall meet the requirements of Table 1. Table 1
Chroma (Pt-Co), No.
Acidity (in HCI), %
Water, %
Acetaldehyde, %
1,1-difluoroethane, %
Carbon tetrafluoride, %
Approved by the State Bureau of Technical Supervision on April 24, 1992Superior products
First-class products
Qualified products
1993-0 2-01 Implementation
Ethanol, %
Chloroacetaldehyde, %
GB4118—92
Continued Table 1
Superior Products
Qualified Products
3.3Acetaldehyde only tests the trichloromethane produced by the acetaldehyde method, 1,1-dichloroethane only tests the trichloromethane produced by the methane chlorination method, dichloroacetaldehyde only tests the trichloromethane produced by the trichloroacetaldehyde alkaline hydrolysis method; ethanol! Tests the trichloromethane produced by the trichloroacetaldehyde alkaline hydrolysis method and the stabilizer. 4 Test Methods
The reagents and water used in this standard, unless otherwise specified, refer to analytical reagents and laboratory distilled water or water of equivalent purity. 4.1 Determination of chromaticity
Carry out according to the method specified in GB3143.
4.2 Determination of acidity
Perform the method specified in GB4120.3. 4.3 Determination of moisture
Perform the method specified in GB4120.5. If there is a dispute between the supply and demand parties, the method specified in GB6283 shall be used as the arbitration method. 4. 4 Determination of acetaldehyde—
4.4.1 Principle
4.4.2 Reagents and solutions
Alkaline hydrolysis titration method
CCI,CHO+NaOH--CCI,H+CHOONa
NaOH+1/2H,S0,—-91/2NaSO,+H,04.4.2.1.0.01g/mlL phenolic acid ethanol solution; 4.4.2.2 Standard titration solution of sodium hydroxide (NaOH) = 0.mol/L); 4.4.2.3 Standard titration solution of sulfuric acid rc (1/2H,S0) -0.1mul/L): 4.4.3 Apparatus
250mL two-corner flask; 10mL pipette; ? burettes each for acid and alkali. 4.4.4 Analysis steps
Accurately pipette 10.0 mL of sample into a conical flask containing about 80 mL of distilled water. After shaking, add 3 drops of phenolic acid indicator and a micronized standard titration solution of sodium hydroxide (c(Nat)H2O)-0.1 mol/L (do not record the reading) to make the solution appear light red. Then, accurately add 25.00 mL of 0.1 mol/L NaOH standard titration solution from the burette, shake well and let stand for 2 min, then add 3 drops of phenol, and finally titrate with sulfuric acid standard titration solution (c(deficient H,SO,) = 0.1 mol/L) until it turns light red, and record the reading. 4. 4. 5 Calculate
(cV/ — c,V2) × 0.147 4 × 10010.0×1.48
blue chloroacetaldehyde mass percentage content;
ci, t: — are the actual concentrations of sodium hydroxide and sulfuric acid standard titration solutions, mol/L; V, V are the consumed volumes of sodium hydroxide and sulfuric acid standard titration solutions, mL; 0.147 4-
Mass of aldehyde;
Density of chloroethylene-chloroform in g/cm°, equivalent to 1.00ml sodium hydroxide standard titration solution e(NaOH)=1.000mol/L.
4.5 Determination of purity and components
This method uses the alkoxylation method, GB 4118—92
The components in chloroform produced by chloroacetaldehyde alkaline hydrolysis, acetaldehyde method and photochlorination method are detected by thermal conductivity detector and the content of each component is calculated by normalization method.
4.5.1 Materials and reagents
4.5.1.1 Carrier gas: hydrogen. Purity better than 99.5%. 4.5.1.2 Carrier: 6201 carrier, particle size 0.20~0.28mm, 0.15~0.20mm. 4.5 .1.3 Stationary liquid: dibutyl phthalate and ethylene glycol 2000. 4.5.1.4 Solvent: acetone.
4.5.2 Instruments
4.5.2.1 Gas chromatograph: equipped with a thermal conductivity detector (using hydrogen as carrier gas, the sensitivity to benzene is better than 800mV·mL/mg). 4.5.2.2 Injector: micro-injector.
4.5.2.3 Chromatographic column: 3m long, 3~4mm inner diameter stainless steel Steel column. 4.5.3 Analysis steps
4.5.3.1 Stationary phase, weigh 5.0g of ethylene glycol 2000 (column 1); 1.0g of ethylene glycol 2000 (column 2) in a 250mL beaker, use acetone as solvent, and heat on a water bath to completely dissolve it. Then weigh 15.0g of dibutyl phthalate (column 1) and 19.0g of dibutyl phthalate (column 2). Mix the two. Then slowly pour 100g of 6201 carrier into each, Make it completely wet and evenly coated. After the solution evaporates, move it to an infrared lamp for drying.
4.5.3.2 Filling and loading amount of the chromatographic column: plug the outlet of the chromatographic column with a little glass wool or copper mesh, then suck from the outlet, and load the stationary phase into the chromatographic column under gentle vibration. For a stainless steel column with an inner diameter of 3mm, the loading amount is about 3g/m. 4.5.3.3 Aging of the chromatographic column: Pass the carrier gas and age the chromatographic column at 90~100℃ for 8h. 4.5.3.4
Typical chromatographic conditions, as shown in Table 2:
Vaporization temperature,
Detection temperature.℃
Column temperature,
Carrier gas flow rate, ml./min
Bridge voltage, mA
Injection volume μL
Record only range, mV
Column No. 1
Users can adjust the chromatographic conditions appropriately, but should obtain appropriate separation. Column No. 2 is generally suitable for samples with poor separation of dichloromethane and 1,1-dioxane Column No. 2
4.5.3.5 Determination: Start the instrument, and inject the sample after the chromatographic operating conditions are stable. The retention time and relative adjusted retention time of each component, as well as the chromatogram are shown in Table 3, Table 4, Figure 1, and Figure 2. Group
Trans-1,2-dichloroethylene
Dichloromethane
1,1-dichloroethane
Carbon tetrachloride
Title 1,2-dichloroethylene
Trichloromethane
1,2-dichloroethane
Trans-1,2-dichloroethylene
Dichloromethane
1,1-dichloroethane
Sulfonic acid tetraoxide
Cis 1,2-Dichloroethylene
Chloroform
GB 4118—92
Continued Table 3
Chromatogram of each dimension on DBP:PEG:62U1=15t5:100 column Figure 1
1—Air; 2—Acetaldehyde 13—Trans-1,2-difluoroethane: 4—Ethanol; 5—Dichloromethane, 6—1,1-difluoroethane, 7—Carbon tetrachloride: 8—Cis-1,2-dichloroethylene; 9—Chloroform; 10—1,2-3-fluoroethane
GB4118—92
Figure 2 Chromatogram of each component on DBP:PEG:6201=19:1:10U column. 1-air; 2-trans-1,2-dichloroethylene=3-difluoromethane+4-11-dichloroethane; 5-carbon tetrachloride: 6-cis-1,2-dichloroethylene, 7-trifluoromethane 4.5.4 Calculation
4.5.4.1 Determine the peak area of each component in trichloromethane and calculate the mass percentage content of each component by normalization method according to formula (2) r;. ,A,) ×(100 - r)
where: f—-relative positive factor of component i, A,—peak area of component i; cm;
—→ mass percentage content of trifluoroacetaldehyde (4.4). 4.5.4.2 The correction factors of each component on the thermal conductivity detector are shown in Table 5. Table 5
Trans-1,2-chloroethylene
Dichloromethane
1,1-dichloromethane
Carbon tetramine
Chloroform
1,2-difluoroethylene
1,2-dichloroethane
4.5.5 Allowable error
GB 4118-92
The difference between the results of two parallel determinations for trichloromethane content shall not exceed 0.2%, and the arithmetic mean shall be taken as the determination result. 5 Inspection rules, packaging, marking, storage and transportation shall be carried out in accordance with the provisions of GB4120.6.
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Beijing Research Institute of Chemical Industry of the Ministry of Chemical Industry. This standard was jointly drafted by the Beijing Research Institute of Chemical Industry, Shanghai Fluorine and Alkali General Factory Electrochemical Plant, Sichuan Honghe Chemical General Factory, etc. The main drafters of this standard are Yang Junqing, Li Lanqing, Wei Changjie, Zhang Jianhui and Ye Xuezhai. This standard adopts the Soviet national standard [OCT20015-74 "Technical Conditions for Industrial Trifluoromethane".
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