1、July 2015 Translation by DIN-Sprachendienst.English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 7
2、5.080; 75.100!%D9.“2332211www.din.deDDIN ISO 6618Petroleum products and lubricants Determination of acid or base number Colour-indicator titration method (ISO 6618:1997),English translation of DIN ISO 6618:2015-07Minerallerzeugnisse und Schmierstoffe Bestimmung von Sure- oder Basenzahl Farbindikator
3、-Titration (ISO 6618:1997),Englische bersetzung von DIN ISO 6618:2015-07Produits ptroliers et lubrifiants Dtermination de lindice dacide ou de lindice de base Mthode par titrage en prsence dun indicateur color (ISO 6618:1997),Traduction anglaise de DIN ISO 6618:2015-07SupersedesDIN 51558-1:1979-07ww
4、w.beuth.deDocument comprises 19 pagesIn case of doubt, the German-language original shall be considered authoritative.07.15Contents Page National foreword . 3 National Annex NA(informative) Bibliography. . 4 National Annex NB (informative) Guidance on using Annex B Determination of pHr-range _ ofp-n
5、aphtholbenzein indicator 5 NB.1 General . 5 NB.2 Reagents aqnd materials (ISO 6619:1988, Clause 4 applies analogously) . 5 NB.3 Apparatus (ISO 6619:1988, Clause 5 applies analogously) 7 NB.4 Preparation of electrode system . 8 1 Scope . 9 2 Normative references 9 3 Definitions . 10 4 Principle . 10
6、5 Reagents and materials 10 6 Apparatus . 12 7 Preparation of used oil sample. 12 8 Determination of acid number . 12 9 Determination of base number 13 10 Determination of strong acid number 13 11 Calculation . 13 12 Expression of results 14 13 Precision 14 14 Test report 15 Annex A (normative) Spec
7、ification for p-naphtholbenzein 16 A.1 Appearance 16 A.2 Chloride content 16 A.3 Solubility 16 A.4 Minimum absorbance 16 A.5 pH range . 16 Annex B (normative) Determination of pHr range of p-naphtholbenzein indicator 17 B.1 Scope . 17 B.2 Definition . 17 B.3 Principle . 17 B.4 Reagents and materials
8、 17 B.5 Apparatus . 18 B.6 Preparation of electrode system . 18 B.7 Standardization of apparatus . 18 B.8 Procedure 19 B.9 Expression of results 19 2IDIN ISO 6618:2015-07A comma is used as the decimal marker. National foreword This document (ISO 6618:1997) has been prepared by Technical Committee IS
9、O/TC 28 “Petroleum products and lubricants”. The responsible German body involved in its preparation was the DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-06-84 AA Gemeinschaftsausschuss NA 062-06-42 AA/NA 062-06-61 AA of the Fachausschuss M
10、inerall- und Brennstoffnormung (FAM). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent rights. The DIN Standards corresponding to the International Standards
11、referred to in this document are as follows: ISO 3696 DIN ISO 3696 ISO 3771 DIN 51639-1 Amendments This standard differs from DIN 51558-1:1979-07 as follows: a) the content of DIN 51558-1 has been adopted in ISO 6618; b) an informative national Annex NB has been included providing essential guidance
12、 based on ISO 6619. Previous editions DIN DVM 3658: 1932-11 DIN DVM 3658 = DIN 53658: 1936-02 DIN 51558: 1955x-06 DIN 51558-1: 1975-08, 1979-07 3IDIN ISO 6618:2015-07National Annex NA (informative) Bibliography DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN 5163
13、9-1, Testing of lubricants Test methods Part 1: Determination of total base number ISO 6619:1988, Petroleum products and lubricants Neutralization number Potentiometric titration method 4IDIN ISO 6618:2015-07National Annex NB (informative) Guidance on using Annex B Determination of pHr-range of p-na
14、phtholbenzein indicator NB.1 General Knowledge of some of the information in ISO 6619:1988 is necessary in order to apply DIN ISO 6618. Because ISO 6619 will not be adopted in full as a national standard, the above-mentioned information which is necessary to apply Annex B of the present document is
15、given below, with some explanatory notes. In case of doubt, refer to ISO 6619. NB.2 Reagents and materials (ISO 6619:1988, Clause 4 applies analogously) NB.2.1 2,4,6-Trimethylpyridine, (-Collidine) (CH3)3C5H2N (molar mass = 121,18 g/mol) conforming to the following requirements: Distillation range:
16、168 C to 170 C; Refractive index, 20Dn : 1,498 2 0,000 5; Colour: colourless Store the reagent over activated alumina and keep it in a brown glass bottle. WARNING 2,4,6-Trimethylpyridine is hazardous if swallowed, breathed or spilled on skin or eyes. Wear chemical safety goggles, neoprene or rubber
17、gloves and apron. Use only in a well-ventilated hood, or wear an approved respirator or a supplied-air respirator. NB.2.2 3-Nitrophenol, NO2C6H4OH (molar mass = 139,11 g/mol) conforming to the following requirements: Melting point: 96 C to 97 C; Colour: pale yellow Store the reagent in a brown glass
18、 bottle. WARNING 3-Nitrophenol is hazardous if swallowed, breathed or spilled on skin or eyes. Wear chemical safety goggles, neoprene or rubber gloves and apron. Use only in a well-ventilated hood, or wear an approved respirator or a supplied-air respirator. 5IDIN ISO 6618:2015-07NB.2.3 Propan-2-ol,
19、 anhydrous, conforming to the following requirement: less than 0,1 % (m/m). If an adequately dry agent cannot be procured, it can be dried by distillation through a multiple plate column, discarding the first 10 % (V/V) of material distilling overhead and the residue of about 10 % (V/V). Drying can
20、also be accomplished using molecular sieves such as Linde Type 4AN1), by passing the solvent upward through a molecular sieve column using one part of molecular sieve per ten parts of solvent. NB.2.4 Hydrochloric acid, c(HCl) = 0,2 mol/l standard volumetric alcoholic solution. Prepare in accordance
21、with NB.2.4.1 or use commercially available solution. Standardize in accordance with NB.2.4.2. NB.2.4.1 Preparation Mix 18 ml of concentrated HCl density at 20 C = 1,19 g/ml with 1 l of propan-2-ol (NB.2.3). NB.2.4.2 Standardization Standardize frequently enough to detect changes of 0,000 5 mol/l, p
22、referably by electrometric titration of 8 ml 0,1 ml of the 0,2 mol/l alcoholic KOH-solution (NB.2.5.1) diluted with 125 ml of carbon dioxide-free water. NB.2.5 Potassium hydroxide, c(KOH) = 0,2 mol/l standard volumetric alcoholic solution. Prepare in accordance with NB.2.5.1 or use commercially avai
23、lable solution. Standardize in accordance with NB.2.5.2. NB.2.5.1 Preparation Add 12 g to 13 g of solid KOH to approximately 1 I of propan-2-ol, anhydrous, (NB.2.3) in a 2-litre conical flask. Boil the mixture gently for 10 min and stir the solution until KOH is completely dissolved. Add at least 2
24、g of barium hydroxide Ba(OH)2 and again boil gently for 5 min to 10 min. Allow to cool to room temperature, and then to stand for two days. Filter the supernatant liquid through a fine sintered-glass or porcelain filtering funnel; avoid unnecessary exposure to carbon dioxide during filtration. Store
25、 the solution in a chemically resistant dispensing bottle out of contact with cork, rubber or saponifiable stopcock lubricant and protected by a guard tube containing soda lime or nonfibrous soda silicate absorbent. Glass bottles are not recommended for storage. NB.2.5.2 Standardization Standardize
26、frequently enough to detect changes of 0,000 5 mol/l, preferably by electrometric titration against 0,2 g to 0,3 g of pure potassium acid phthalate (5.9) (dried at 105 C for 2 h) weighed with an accuracy of 0,000 2 g and dissolved in approximately 100 ml of carbon dioxide-free water. N1) National fo
27、otnote: Linde Type 4A is an example of a suitable product available commercially. This information is given for the convenience of users of this standard and does not constitute an endorsement by DIN of this product. 6IDIN ISO 6618:2015-07NB.2.6 Buffer stock solution A, acidic buffer solution (pHr =
28、 4,0) Accurately weigh 24,2 g 0,1 g 2,4,6-Trimethylpyridine (NB.2.1) and transfer to a 1-litre volumetric flask containing 100 ml of anhydrous propan-2-ol (NB.2.3). Using a 1-litre graduated cylinder, add to the flask, while continuously stirring its contents, (150/c1) ml 5 ml 0,2 mol/l alcoholic HC
29、l solution (NB.2.4) (c1being the exact molarity concentration of the HCl solution as found by standardization). Dilute to the 1000 ml mark with anhydrous propan-2-ol (NB.2.3) and mix thoroughly. Use within one month. NB.2.7 Buffer stock solution B, basic buffer solution (pHr = 11,0) Accurately weigh
30、 27,8 g 0,1 g of 3-Nitrophenol (NB.2.2) and transfer to a 1-litre volumetric flask containing 100 ml of anhydrous propan-2-ol (NB.2.3). Using a 1-litre graduated cylinder, add to the flask, while continuously stirring its contents, (50/c2) ml 1 ml 0,2 mol/l alcoholic KOH solution (NB.2.5) (c2being t
31、he exact molarity concentration of the KOH solution as found by standardization). Dilute to the 1000 ml mark with anhydrous propan-2-ol (NB.2.3) and mix thoroughly. Use within one month. NB.2.8 Titration solvent Add 500 ml of toluene and 5 ml of water to 495 ml of propan-2-ol (NB.2.3). The titration
32、 solvent should be made up in large quantities, and its blank value determined daily by titration prior to use. NB.3 Apparatus (ISO 6619:1988, Clause 5 applies analogously) NB.3.1 pH meter The potentiometer shall operate with an accuracy of 0,005 V and a sensitivity of 0,002 V over a range of at lea
33、st 0,5 V when used with the electrodes specified in NB.3.2 and NB.3.3 and when the resistance between the electrodes falls within the range of 0,2 M and 20 M. The meter and the titration apparatus shall be protected from stray electrostatic fields so that no permanent change in the meter readings ov
34、er the entire operating range is produced by touching, even with a grounded lead, any part of the electrodes, the electrode lead, the titration stand or the meter. Manual potentiometers with or without recorder or automatic potentiometers can be used. NB.3.2 Glass electrode The body of the electrode
35、 shall be made of a chemically resistant glass tube and, at a temperature of 25 C, shall have a resistance within the range of 100 M and 1 000 M. The wire leading to the potentiometer shall be properly shielded. NB.3.3 Reference electrode, Calomel electrode Connection between the reference electrode
36、 and the solution is made by a potassium chloride bridge. NOTE The use of single-rod glass electrodes has been found suitable. NB.3.4 Stirrer, mechanical stirrer, equipped with a glass, propeller-type stirring paddle. If electrical stirring apparatus is used, it shall be grounded so that connecting
37、or disconnecting the power to the motor will not produce a permanent change in meter reading during the course of the titration. NB.3.5 Titration apparatus NB.3.5.1 Burette, 10 ml capacity, graduated in 0,05 ml divisions, and calibrated with an accuracy of 0,02 ml. The burette shall have a glass sto
38、pcock and shall have a tip that extends 100 mm to 130 mm beyond the stopcock. The burette shall have a guard tube containing a CO2-absorbing indicator solution. NB.3.5.2 Titration beaker, 250 ml capacity, made of borosilicate glass. 7IDIN ISO 6618:2015-07NB.3.5.3 Titration stand, suitable for suppor
39、ting the electrodes, burette and stirrer. NB.4 Preparation of electrode system Preparation, maintenance and use of the electrode system should be in accordance with the manufacturers instructions or ISO 6619:1988-12, Clause 7. 8IDIN ISO 6618:2015-07Petroleum products and lubricants - Determination o
40、f acid or base number - Colour-indicator titration method WARNING -The use of this International Standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of t
41、his International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies a colour-indicator titration method for the determination of acidic or basic constituents in petroleum
42、 products and lubricants soluble in mixtures of toluene and propan-2-01. It is applicable for the determination of acids or bases whose dissociation constants in water are greater than 10-g; extremely weak acids or bases whose dissociation constants are less than IO-9 do not interfere. Salts react i
43、f their hydrolysis constants are greater than 10-g. NOTE 1 In new and used oils, the constituents considered to have acidic characteristics include organic and inorganic acids, esters, phenolic compounds, lactones, resins, salts of heavy metals, and additives such as inhibitors and detergents. Simil
44、arly, constituents considered to have basic properties include organic and inorganic bases, amino compounds, salts of weak acids (soaps), basic salts of polyacidic bases, salts of heavy metals, and additives such as inhibitors and detergents. The method is not suitable for measuring the basic consti
45、tuents of many basic additive-type lubricating oils, for which IS0 3771 can be used. This International Standard indicates relative changes that occur in an oil during use under oxidizing conditions. Although the titration is made under definite equilibrium conditions, the method does not measure an
46、 absolute acidic or basic property that can be used to predict performance of an oil under service conditions. NOTES 2 No general relationship between bearing corrosion and acid or base number is known. 3 Oils, such as many cutting oils, rustproofing oils, and similar compounded oils, or excessively
47、 dark-coloured oils, that cannot be analysed by this method owing to obscurity of the colour-indicator end-point, can be analysed in accordance with IS0 6619. The acid or base numbers obtained by this colour-indicator method may or may not be numerically the same as those obtained by IS0 6619, but t
48、hey are generally of the same order of magnitude. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
49、 revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. 9IDIN ISO 6618:2015-07IS0 3696: 1987, Water for analytical laboratory use - Specification and test methods. IS0 6619:1988, Petroleum products and lubricants - Neutralization number - Po ten tiome tric titration method.
