Diethyl oxalate for industrial use (3)

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The non-polar components in the sample are extracted by carbon tetrachloride , and the free acid is extracted by water to separate the organic phase from the water phase, and then the acid content in the water phase is titrated with an alkali standard titration solution

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Separation funnel: 250mL capacity

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Weight reduction method Weigh about 20g of the sample (accurate to 0.

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The content X ₂ of acid ( calculated as H ₂ C ₂ O ₄ ) expressed in mass percentage is calculated according to formula (2):

In the formula: V—the volume of the sodium hydroxide standard titration solution consumed by the titration sample, mL;

c ₂ —The actual concentration of sodium hydroxide standard titration solution, mol/L;

m ₂ —the mass of the sample, g;

0.

Take the arithmetic mean of the two parallel determination results as the determination result

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4 Determination of moisture

Weigh about 2g of the sample (accurate to 0.
01g) and measure it according to "Chapter 7 Direct Coulometric Titration" in GB/T6283-1986
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Take the arithmetic mean of the two parallel determination results as the determination result
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The difference between the two parallel determination results shall not exceed 0.
01%
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5 Determination of evaporation residue

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1 Method summary

After the sample is heated and evaporated to dryness, it is dried at (110±2)°C and weighed until the mass is constant
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2 Instruments and equipment

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2.
1 Evaporating dish: made of materials such as platinum, quartz or borosilicate glass, with a capacity of 100 mL
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2 Electric furnace: the power of the wire is 300W
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3 Voltage regulating transformer
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3 Analysis steps

Place the evaporating dish in an oven, heat it at (110±2)°C for 1h, take it out, put it in a desiccator to cool for 45min, and weigh it until the mass is constant
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Weigh about 50g of the sample (accurate to 0.
1g), place it in a constant-weight evaporating dish, place it on an electric furnace with an asbestos board, and heat it with a control voltage of 120V～130V, and evaporate to dryness in a fume hood.
Less than 30min
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Remove the evaporating dish from the electric furnace, wipe the outside of m with lens paper, and place it in a pre-heated oven at (110±2)℃, heat it for 2h, take it out, put it in a desiccator to cool for 45min, and weigh it.
To constant quality
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4 Expression of analysis results

The evaporation residue content X ₃ expressed in mass percentage is calculated according to formula (3):

In the formula: m ₄ -the mass of evaporation residue, g;

m ₃ —the mass of the sample, g
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Take the arithmetic mean of the two parallel determination results as the determination result
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The difference between the two parallel determination results shall not exceed 0.
002%
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5 Inspection rules

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1 All items specified in this standard are type inspection items, among which ester content, distillation test, acidity, and moisture are ex-factory inspection items
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Under normal circumstances, type inspection will be carried out once every half a month
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2 Diethyl oxalate for industrial use should be inspected by the quality inspection department of the manufacturer
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The manufacturer shall ensure that all manufactured products meet the requirements of this standard
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Each batch of products should be accompanied by a quality certificate in a certain format, which includes the product name, product grade, manufacturer name, factory address, batch number or production date and the number of this standard
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3 The user has the right to check and accept the products received in accordance with the provisions of this standard
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Any objections should be raised to the manufacturer within half a year after receiving the product
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4 Diethyl oxalate for industrial use shall be a batch of homogeneous products of the same quality (the quality of each batch shall not exceed 20t); or a batch of one production unit can be filled
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5 The number of sampling units shall be determined in accordance with 6.
6 of GB/T6678-1986
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The sampling technique should meet the requirements of GB/T6680
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When sampling, the insertion depth of the sampling glass tube is not less than 3/4 of the barrel to ensure that the sample taken is representative of the upper, middle, and lower layers
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The total sample volume is not less than 800 mL, and the mixture is evenly mixed and then packed into two clean, dry 500 mL glass bottles with a ground mouth
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Affix the label and indicate the product name, product grade, batch number, sampling date and the name of the sampler
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One bottle is for inspection, the other is sealed and kept for two months for future reference
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6 The test result is judged according to the rounding value comparison method in GB/T1250
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If one of the inspection results does not meet the requirements of this standard, samples should be taken from twice the number of packaging units for re-inspection, and canned products should be sampled at multiple points for inspection
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Even if only one index does not meet the requirements of this standard as a result of the re-inspection, the whole batch of products is unqualified
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6 Marking, packaging, transportation and storage

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1 The packaging container of diethyl oxalate for industrial use should have a firm and clear mark, which includes the product name, trademark, manufacturer name, site, net content, batch number, number of this standard, and the "drug" mark specified in GB190 And GB/T191 stipulates the signs of "being afraid of the sun", "being afraid of rain" and "temperature limit" (the temperature shall not be higher than 60℃)
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2 Diethyl oxalate for industrial use should be put into clean and dry 200L closed steel drums or galvanized iron drums
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The net weight per barrel is 200kg
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3 The storage and transportation temperature of diethyl oxalate for industrial use shall not be higher than 60℃, and shall be protected from moisture, rain, fire and oxides; the transportation shall comply with the regulations for the transportation of dangerous goods
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7 Security

Industrial diethyl oxalate is an organic liquid with certain toxicity
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It reacts with oxidants and has the risk of burning; it is decomposed by high heat or burning to liberate toxic gases; it is easily hydrolyzed into acids and alcohols in the body, causing strong corrosiveness and irritation.
Its prominent symptoms are breathing disorders and muscle tremors
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Care should be taken to avoid inhalation of vapors and contact with skin
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