QB/T 2623.3-2003 Soap test method Determination of total alkali content and total fatty matter content in soap
Some standard content:
ICS71.100
Classification number: Y43
Request number: 13169-2004
Light Industry Standard of the People's Republic of China
QB/T2623.3-2003
Replaces QB/T3750-1999
Test methods of soaps
Determination of total alkali content and total fatty matter content in soaps(ISO685:1975,Analysis of soaps-—Determinationof total alkali QB/T2623.3—2003 This standard is the third standard in the QB/T2623 series of standards "Test methods for soap". This series of standards consists of eight standards, and the names of the standards are as follows: QB/T2623.1 Test methods for soap Determination of free alkali content in soap QB/T2623.2 Test methods for soap Determination of total free alkali content in soap QB/T2623.3 Test methods for soap Determination of total alkali content and total fatty matter content in soap QB/T2623.4 Test methods for soap Determination of moisture and volatile matter content in soap Oven method Test methods for soap Ethanol insoluble in soap Determination of total alkali content in soap QB/T2623.5
QB/T2623.6
OB/T2623.7
Test method for soap Determination of nitrogen content in soap Titration method Test method for soap Determination of unsaponifiable and unsaponifiable matter in soap QB/T2623.8 Test method for soap Determination of phosphate content in fertilizer This standard is a revision of QB/T3750-1999 "Determination of total alkali salt and total fatty matter content in fertilizer". This standard is revised and adopted ISO685:1975 "Analysis of soap - Determination of total alkali content and total fatty matter content" (English version). This standard is redrafted based on ISO685:1975. According to my country's national conditions and laboratory verification, this standard has been modified when adopting the international standard. These technical differences are marked with a straight single line in the right margin of the page where they are related. A list of technical differences and their reasons is given in Appendix A for reference. For ease of use, this standard has also made the following editorial changes: a) "this international standard" is changed to "this standard"; b) the decimal point "", is used instead of the return sign "", which is used as a decimal point; c) the foreword of the international standard is deleted.
Appendix A of this standard is an informative appendix.
This standard is proposed by the China Light Industry Federation. This standard is under the jurisdiction of the National Surfactant Detergent Standardization Center. This standard is drafted by the National Detergent Quality Supervision and Inspection Center (Taiyuan). The main drafters of this standard are Liang Hongyan and Yan Fang. This standard was first issued as the national standard GB/T7457-1987 in March 1987, and was converted into the light industry standard QB/T3750-1999 in April 1999. This is the first revision. From the date of implementation, this standard replaces the light industry standard QB/T3750-1999 "Determination of total alkali content and total fat content in soap" issued by the former State Bureau of Light Industry.
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1 Scope
QB/T2623.3-2003
Test methods for soap
Determination of total alkali content and total fat content in soap This standard specifies a method for simultaneously determining the total alkali content and total fat content in soap. This standard applies to soaps with fatty acid salts as active ingredients, but does not apply to colored soaps and compound soaps. 2 Normative references
The clauses in the following documents become clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard. GB/T601-2002 Preparation of standard titration solutions for chemical reagents GB/T603-2002 Preparation of preparations and products used in test methods for chemical reagents QB/T2623.1-2003 Test methods for soaps Determination of free caustic content in soaps 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Total alkali
refers to the sum of all silicates, carbonates and hydroxides of alkali metals, and alkalis combined with fatty acids and resin acids that can be titrated under specified conditions. The results can be expressed as a percentage of sodium hydroxide or potassium hydroxide, depending on whether it is sodium soap or potassium soap. 3.2
Total fatty matter
refers to the water-insoluble fatty matter obtained by decomposing soap with inorganic acids under specified conditions. In addition to fatty acids, total fatty matter also includes unsaponifiable matter, glycerides and some resin acids in soap.
dried sodium soap
refers to the sodium salt form of total fatty matter.
4 Test method
Unless otherwise specified, only reagents of confirmed analytical grade and distilled or deionized water or water of equivalent purity shall be used in the analysis. 4.1 Principle
Soap is decomposed with a known volume of standard inorganic acid, the precipitated fatty matter is separated by extraction with petroleum ether, and the perhydrochloric acid in the aqueous solution is titrated with a standard sodium hydroxide solution to determine the total alkali content. After evaporating the petroleum ether in the extract, the residue is dissolved in ethyl alcohol and the fatty acids are neutralized with a standard potassium hydroxide solution. Ethanol is evaporated and the soap formed is weighed to determine the total fatty matter content. 4.2 Reagents and materials
a) Acetone (GB/T686);
b) Petroleum ether (HG/T31003), boiling range 30℃～60℃, no residue; 95% ethanol (GB/T679), freshly boiled and cooled, neutralized with alkali to be neutral to phenol; e)
QB/T2623.3—2003
Sulfuric acid (GB/T625) or hydrochloric acid (GB/T622), c(-H,SO) or c(HCI)=1mol/L standard titration solution, prepared and calibrated according to 4.3 or 4.2 of GB/T6012002; e)
Sodium hydroxide (GB/T629), c(NaOH)=1mol/L standard titration solution, prepared and calibrated according to GB/T601 ～2002, prepared according to 4.1.1, methyl orange solution (4.2.g) as indicator, calibrated with sulfuric acid or hydrochloric acid (4.2.d): Potassium hydroxide (GB/T2306), c (KOH) = 0.7 mol/L ethanol standard titration solution, prepared and calibrated according to f)
4.24 in GB/T601-2002;
methyl orange, 1g/L solution, prepared according to 4.1.4.8 in GB/T603-2002: g)
phenol (GB/T10729), 10g/L indicator solution, prepared according to 4.1.4.22 in GB/T603-2002: i) thymol blue (GB/T15353), 1g/L indicator solution, prepared according to 4.1.4.12 in GB/T603-2002. 4.3 Apparatus
Ordinary laboratory apparatus and
4.3.1 Beaker, tall type, 100mL.
Separatory funnel, 500mL or 250mL.
4.3.3 Benzene measuring cylinder, equipped with ground glass stopper, Φ39mm, height 350mm, 250mL. 4.3.4 Water bath, temperature controllable.
4.3.5 Oven, controllable at (103±2)℃. 4.3.6 Soxhlet extractor.
4.4 Preparation and storage of samples
Prepare and store in accordance with the provisions of 3.4 of QB/T2623.1-2003. 4.5 Procedure
The same sample shall be measured in duplicate.
4.5.1 Test portion
Weigh the soap sample (accurate to 0.001g), refer to the following: 1. Laundry soap: 5g:
(Semi) transparent soap: 4.5g:
Toilet soap: 4.2g.
4.5.2 Determination
Solubility test portion (4.5.1) In 80mL hot water. Stir with a glass rod until the test sample is completely dissolved, then transfer it to a separatory funnel (4.3.2) or an extraction cylinder (4.3.3) with a warm temperature. Wash the beaker with a small amount of hot water, and add the washing water to the separatory funnel or extraction cylinder. Add a few drops of methyl orange solution (4.2.g), and then while shaking the separatory funnel or benzene extraction cylinder, accurately add a certain volume of sulfuric acid or hydrochloric acid standard titration solution (4.2.d) from the burette to make an excess of about 5mL. Cool the contents of the separatory funnel or extraction cylinder to about 30℃~40℃, add 50mL of petroleum ether (4.2.b), cover the stopper, hold the stopper tightly and slowly invert the separatory funnel or extraction cylinder, gradually open the stopcock of the separatory funnel or the stopper of the extraction cylinder to release the pressure, then close it, shake gently, and release the pressure again. Repeat the shaking until the water layer is transparent, and let it stand to separate. When using a separatory funnel:
Put the lower water layer into the second separatory funnel (4.3.2) and extract with 30mL of non-oil ether (4.2.b). Repeat the above operation, collect the water layer in a conical flask, and combine the three petroleum ether extracts in the first separatory funnel. When using an extraction volume:
Use the siphon effect to draw the non-oil ether layer into the separatory funnel (4.3.2) as completely as possible. Repeat the extraction twice with 50mL of petroleum ether (4.2.b), and add the three petroleum ether benzene extracts into the separatory funnel. Transfer the water layer to the conical flask as completely as possible, wash the benzene extract with a small amount of water, and add the washing water to the conical flask. Add 25mL of water and shake the petroleum ether benzene extract several times until the washing liquid is neutral to the methyl orange solution (4.2.g). Generally, three washes are sufficient.
Note: After each washing, let it stand for at least 5 minutes. The water layer can be released only when there is a clear interface between the two liquid layers. After the last washing water is released, turn the separatory funnel sharply, but do not turn it upside down, so that the contents can swirl to remove the water droplets attached to the wall. 2
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Quantitatively collect the washing liquid of the petroleum ether extract into the conical flask containing the water layer liquid. 4.5.3 Determination of total alkali
QB/T2623.3-2003
Use methyl orange solution (4.2.g) as an indicator and titrate the mixture of the acid water layer and the washing water with sodium hydroxide standard titration solution (4.2.e). 4.5.4 Determination of total fat content
Carefully transfer the washed petroleum ether solution (4.5.2) into a weighed flat-bottom flask. Filter through dry filter paper if necessary. Wash the separatory funnel 2-3 times with a small amount of petroleum ether. Filter the washing liquid into the flask. Be careful to prevent the petroleum ether from evaporating during the filtering operation. Make sure that the petroleum ether thoroughly washes the filter paper. Collect the washing liquid into the flask. Use a Soxhlet extractor (4.3.6) on a water bath (4.3.4) to extract almost all the petroleum ether. Dissolve the residue in 10 mL of ethanol (4.2.c), add 2 drops of phenolic acid solution (4.2.h), and titrate with potassium hydroxide ethanol standard titration solution (4.2.f) until a stable light pink color is reached as the end point. Record the volume consumed.
Note: If the color of the colored soap will interfere with the end point of the phenol peptide indicator, thymol blue indicator (4.2.i) can be used. Ethanol is evaporated on a water bath. When the ethanol is almost evaporated, rotate the flask to form a thin layer of potassium soap on the flask wall. Rotate the flask, add about 5 mL of acetone (4.2.a), slowly rotate on a water bath to evaporate the acetone, and repeat the operation 1 to 2 times until there is no obvious wet mark at the mouth of the flask, so that the potassium soap is pre-dried. Then heat in an oven at (103 ± 2) ℃ to constant weight, that is, heat for 4 hours for the first time and 1 hour each time thereafter. After cooling in a desiccator, weigh until the difference between two consecutive weighings is no more than 0.003g. 4.6 Calculation of results
4.6.1 Total alkali content
4.6.1.1 Calculation method and formula
a) The total alkali content in soap is expressed as the mass percentage of sodium hydroxide (NaOH, %) for sodium soap and calculated according to formula (1): Total alkali content (NaOH, %) = 0.040 × (V × -V) × 100m
The total alkali content in soap is expressed as the mass percentage of potassium hydroxide (KOH, %) for potassium soap and calculated according to formula (2): b)
0. 056×(V×c.-×c)×100
Total alkali content (KOH%)=
Wherein:
Vo—the volume of the acid standard solution added in the determination, mLCo
-the molar concentration of the acid standard solution used, mol/L;-the volume of the sodium hydroxide standard titration solution consumed, mL:m
-the molar concentration of the sodium hydroxide standard titration solution used, mol/L;-the millimole mass of sodium hydroxide expressed in grams in the test, g/mmol;0.056--the millimole mass of potassium hydroxide expressed in grams in the test, g/mmol;m
the mass of the test portion, g.
The arithmetic mean of the results of two parallel determinations is expressed to one decimal place as the determination result. The total alkali content can also be expressed as the number of millimoles per gram (mmol/g), such as formula (3): Total alkali content=×c. -V×c
4.6.1.2 Precision
(1)
(3)
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 0.2%, provided that the difference shall not exceed 5% if it exceeds 0.2%.
4.6.2 Total fat content
4.6.2.1 Calculation method and formula
The total fat content in soap is expressed as mass percentage and is calculated according to formula (4): 3
QB/T2623.3-2003
Total fat (%) = [m-(V×c×0.038)]xm.
The dry sodium soap content in soap is expressed as mass percentage and is calculated according to formula (5): Dry soap (%) = [m-(V×x0.016)]×100m.
Wherein:
-Mass of dry sodium soap, g:
V-Volume of potassium hydroxide ethanol standard titration solution consumed in neutralization, mL-Molar concentration of potassium hydroxide ethanol standard titration solution used, mol/L;-Difference in millimolar mass of potassium and hydrogen atoms expressed in grams in the test (i.e. 0.039-0.001), g/mmol: 0.038
0.016-Difference in millimolar mass of potassium and sodium atoms expressed in grams in the test (i.e. 0.039-0.023), g/mmol; mo-Mass of test portion, g.
The arithmetic mean of the results of two parallel determinations is expressed to the integer as the determination result. 4.6.2.2 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 0.2%, provided that the difference shall not exceed 5% if it exceeds 0.2%.
4.7 Test report
The test report shall include the following:
a) reference to the method used;
b) analysis results and method of expression;bzxz.net
any abnormal phenomena observed during the measurement;
any operations not included in this standard or optional;
test date.
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Appendix A
(Informative Appendix)
Technical differences between this standard and ISO685:1975 and their causes Table A.1 lists the technical differences between this standard and ISO685:1975 and their causes Table A.1 Technical differences between this standard and ISO685:1975 and their causes Article number of this standard
This standard
The concentration of the standard titration solution of potassium hydroxide in ethanol is 0.7 mol/
Add thymol blue indicator
List three reference amounts of samples Weigh the test portion and dissolve it in 80 mL of hot water
Cool the separating funnel or extract Take the material in the container and bring it to about 30℃~40℃. Add 50mL of petroleum ether. When using a separatory funnel, use petroleum ether and 30mL of benzene. Use a Soxhlet extractor on a water bath to almost extract all the petroleum ether. Dissolve the residue in 10mL of ethanol. Add the note "The colored soap can be titrated with thyme blue indicator". Add about 5mL of two ketones, slowly evaporate the acetone on a water bath, and repeat the operation 1 to 2 times. Heat and dry in a (103±2) oven for 4h the first time and 1h each time thereafter until constant weight.
Specifies repeatability
Adds total lipid content to dry sodium electrochemical calculation formula (5)
Specifies repeatability
Article number
ISO685:1975
Potassium cyanide standard solution of about 1N ethanol
Weigh 5g of laboratory sample
Dissolve the test portion in 100mL of hot water
Cool and allow to about 25℃
Add 100mL of petroleum ether
When using a separatory funnel, extract with 50mL of petroleum ether
Evaporate almost all of the petroleum alcohol on a water bath, and conduct the test under a cold nitrogen
flow or air flow.
Dissolve the residue in 20mL of ethanol
Add an unmeasured amount of acetone
Heat at (103±2)℃ to constant weight
Heat for 15min each time until constant
Specified reproducibility
Only one table method: total fat
matter is calculated as fatty acids
Specified reproducibility
QB/T2623.3-2003
Reduce experimental error
Determine color Electricity needs to be used to control the consumption of sodium hydroxide-ethanol standard solution so that it is not too much or too little. 80mL of water can meet the test to prevent the acidified fat from agglomerating. Too much petroleum ether is not conducive to the later work. Too much petroleum ether is not conducive to the later exploration. Volatile petroleum ether pollution. 10mL of ethanol has met the test.
Necessary in the test
Not conducive to the unification of exploration
No constant weight time is specified, which is not conducive to the unification of operation
Work often needs
Work often needs
Work often needs
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People's Republic of China
Light Industry Industry Standard
Soap Test Method
Determination of Total Alkali and Total Fatty Content in Soap QB/T 2623. 3-2003
Published by China Light Industry Press
Editorial and Publishing Committee of Light Industry Standardization Address: No. 12 Guanghua Road, Chaoyang District, Beijing
(3rd Floor, Building 1, China National Pulp and Paper Research Institute) Ministry Code: 100020
Telephone: (010) 65811585
Copyright reserved. Infringements must be investigated
Book Number: 155019-2606
Print Quantity: 1-200 copies
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