how we can test acidity number ASTMD-974 for motor oil or base oil?

Question

i dont know how to get acidity number in motor oil and how can reduce the number and what is the method to prepare solution for test?

Answer 1

If you mean unused motor oil, it won't have a TAN (Total Acid Number) it'll have a TBN (Total Base Number) as motor oils have alkaline detergent/dispersent additive packs. You perform a TBN titration.

Regardless, the titration dynamic is similar.

The acid number (or "neutralization number" or "acid value" or "acidity") in chemistry is the mass of potassium hydroxide in milligrams that is required to neutralize one gram of chemical substance. The acid number is a measure of the amount of carboxylic acid groups in a chemical compound for instance a fatty acid. In a typical procedure a known amount of sample dissolved in organic solvent is titrated with a solution of potassium hydroxide with known concentration and with phenolphthalein as a color indicator.



ASTM D 974
Title:
Standard Test Method for Acid and Base Number by Color-Indicator Titration



ASTM International



Publication Date:
Nov 1, 2004



Scope:


(Footnote *)

This test method covers the determination of acidic or basic constituents (Note 1) in petroleum products(Footnote 2) and lubricants soluble or nearly soluble in mixtures of toluene and isopropyl alcohol. It is applicable for the determination of acids or bases whose dissociation constants in water are larger than 10−9; extremely weak acids or bases whose dissociation constants are smaller than 10−9 do not interfere. Salts react if their hydrolysis constants are larger than 10−9.

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 addition agents such as inhibitors and detergents. Similarly, 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 addition agents such as inhibitors and detergents.

NOTE 2 - This test method is not suitable for measuring the basic constituents of many basic additive-type lubricating oils. Test Method D 4739 can be used for this purpose.

This test method can be used to indicate 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 absolute acidic or basic property that can be used to predict performance of an oil under service conditions. No general relationship between bearing corrosion and acid or base numbers is known.

NOTE 3 - Oils, such as many cutting oils, rustproofing oils, and similar compounded oils, or excessively dark-colored oils, that cannot be analyzed for acid number by this test method due to obscurity of the color-indicator end point, can be analyzed by Test Method D 664. The acid numbers obtained by this color-indicator test method need not be numerically the same as those obtained by Test Method D 664, the base numbers obtained by this color indicator test method need not be numerically the same as those obtained by Test Method D 4739, but they are generally of the same order of magnitude.

The values stated in acceptable SI units are to be regarded as the standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Footnote * - A Summary of Changes section appears at the end of this standard.

Footnote 2 - Statements defining this test method, its modification, and its significance when applied to electrical insulating oils of mineral origin will be found in Guide D 117.

Answer 2

Read The Motor Oil Bible. To quote: There are two main types of basestocks, petroleum and ynthetic. Petroleum basestocks are a purified form of crude oil and have been used as the base for automotive ubricants since motor oils were first being developed. Synthetic basestocks, on the other hand, are chemically engineered in a lab specifically for the purpose of lubrication. They are engineered from pure compounds that contain no contaminants which must be removed via purification. Synthetic oil is much better. The best is Amsoil, althought Mobil 1 is also very good. The benefits are it lasts much longer, and is cheaper in the long run. Petroleum based oil begins breaking down almost as soon as it is being used. Synthetics perform much better in real bad conditions, like if your engine is overheating, synthetic oil won't break down as soon. I read this whole book.

Answer 3

i think ph meter can be used

Answer 4

how about using a ph meter....

Answer 5

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