We, especially as chemical industry practitioners, often say that structure determines properties. For example, allotropes refer to elemental substances composed of the same single chemical element but with different properties. The same element has different physical and chemical properties due to its arrangement.

Coal, diamond, fullerene, and their constituent elements are all carbon.

Isomers are compounds with the same molecular formula but different atomic arrangements. Simply put, the phenomenon of compounds having the same molecular formula but different structures is called isomerism; Compounds with the same molecular formula but different structures are isomers of each other. Although many isomers have similar properties, overall their chemical properties are different. In organic chemistry, isomers can be substances of the same class (containing the same functional groups) or substances of different classes (containing different functional groups). Ethanol and methyl ether, both composed of C2H60, have completely different properties.

It can be roughly understood that in the field of lubricants, the same type of oil, such as hydraulic oil, can be classified as biodegradable or non biodegradable.

The so-called biodegradation refers to the continuous elimination of materials from the body through dissolution, enzymatic hydrolysis, cell phagocytosis, and other processes during tissue growth. The repaired tissue completely replaces the position of the implanted material, and there is no residual property of the material in the body.

Specifically for lubricants, biodegradable, also known as environmentally friendly, refers to green oil products.

A typical example is that over 80% of the hydraulic oil used in forest mining in Sweden and Germany is green hydraulic oil.

Generally, mineral oil has poor biodegradability and does not decompose even after being exposed to air for 3 years, while green oil products can be degraded into carbon dioxide and water by active microorganisms within 18-28 days.

At present, several major lubricating oil products such as general two-stroke engine oil, chainsaw oil, hydraulic oil, machining lubricants, and food processing machinery lubricants are increasingly using environmentally friendly products.

The International Organization for Standardization (ISO) adopted the ISO/DIS 15380 draft quality standard for green hydraulic oil in June 2000. Divide green hydraulic oil into: ① HETG, environmentally acceptable triglycerides; ② HEPG, environmentally acceptable polyether; ③ HEES, environmentally acceptable synthetic esters; There are four series, including poly (alpha olefin) synthetic oil, that are acceptable in the HEPR environment. Each series contains four viscosity grades: 22, 32, 46, and 68.

There is no unified standard for green hydraulic oil products worldwide, and generally it is required that their biodegradation rate be greater than 80%.

Green hydraulic oil mainly tests its biodegradability and toxicity.

The types of biodegradation tests are divided into ① attenuation test, ② indirect test, and ③ continuous test.

AFNOR-T-90-302, CEC-L-33-T-93, CLOSEDBOTTLE, and others are commonly used in Yuan Jian's experiments;

Indirect testing includes the SCAS method;

There are ROL-ROHEN and KARLSRUHER methods for continuous testing.