In the early 1990s, chemists proposed the concept of "green chemistry" that is different from the traditional concept of "pollution control". It requires that any chemistry-related activity (including the use of chemical raw materials, chemistry and chemical engineering, and final products)

Both human health and the environment should be friendly.

The ideal of green chemistry is to no longer use toxic and harmful substances and no longer produce waste.

From a scientific point of view, green chemistry is an update of the basic content of chemical science; from an environmental point of view, it emphasizes the elimination of pollution from the source; from an economic point of view, it advocates the rational use of resources and energy and reduces production costs, which is in line with sustainability.

development requirements.

Basic principles of green chemistry: ① It is better to prevent and control the generation of pollution than to control the pollution caused; ② Atomic economy (the designed synthesis method should convert as much of the materials used in the reaction process into the final product as possible); ③ As long as it is feasible

, synthetic routes that are low-toxic or non-toxic to humans and the environment should be adopted as much as possible; ④ The designed chemicals should be able to retain their efficacy and reduce their toxicity; ⑤ The use of auxiliary substances (such as solvents, separation reagents, etc.) should be avoided as much as possible, such as

The use should also be non-toxic; ⑥The impact of energy consumption on the environment and economy should be taken into consideration, and energy should be used as little as possible (under normal temperature and pressure); ⑦As long as it is technically and economically feasible, the raw materials should be

Regenerated, not about to be exhausted; ⑧ Try to avoid unnecessary derivatization steps (blocking groups, protection and deprotection, etc.); ⑨ Catalysts (best possible selectivity) are better than stoichiometric reagents; ⑩ Chemical products

After completing its mission, it should be able to degrade into harmless substances and should not remain in the environment; Analytical methods should be further developed to enable real-time online tracking and control of harmful substances before they are generated; During the chemical conversion process, all

The substances and forms of substances are selected to reduce the possibility of chemical accidents (including leaks, explosions, fires, etc.) as much as possible.

The above 12 principles of green chemistry reflect the multi-faceted research work carried out in the field of green chemistry in recent years and also point out the direction of future development of green chemistry. They are gradually accepted by the international chemical community.

The concept of "atom economy" of chemical reactions is one of the core contents of green chemistry. It was first proposed by B.

M．

Professor Trost pointed out that he pointed out that a new standard should be used to evaluate the chemical process, which is the selectivity and atom economy. Atom economy should be considered

It is how many atoms of raw materials enter the product during the chemical reaction. This standard requires both saving non-renewable resources as much as possible and minimizing waste emissions.

The ideal atomic economic reaction is that the atoms in the raw material molecules are 100% converted into products without producing by-products or waste, achieving "zero emission" of waste.

The concept of "atom economy" is now generally recognized.

B.

M．

Trost won the academic award of the 1998 US Presidential Green Chemistry Challenge Award.

(2) Green chemistry in action As the direction and foundation for the future development of the chemical industry, green chemistry has attracted increasing attention from governments, enterprises and academia.

For example, the President's Green Chemistry Challenge Award was established in the United States in 1995 to reward individuals, groups or organizations that have made outstanding achievements in creative research, development and application of the basic principles of green chemistry.

It consists of 5 awards: Academic Award, Small and Medium Enterprise Award, New Synthetic Route Award, New Process Award and Safe Chemical Design Award.

The book "Theory and Practice of Green Chemistry" published in 1998 is a classic work of green chemistry, which details the definition, principles, evaluation methods and development trends of green chemistry.

Green Chemistry, an international magazine sponsored by the Royal Society of Chemistry, was first published in 1999. Its content covers various research results, reviews and other information on clean chemical production technology, and covers international topics through the application or processing of chemicals.

Academic research activities that mitigate environmental impacts.

Following the awards track of some U.S. Green Chemistry Awards, we can see the main achievements and trends of current green chemical process and technology research: ①Developing "atom-economical" reactions In recent years, developing atom-economical reactions has become a key focus of green chemistry research.

One of the hot spots.

For example, propylene oxide is an important raw material for the production of polyurethane plastics. Traditionally, the chlorohydrin method with a two-step reaction is mainly used, which not only uses potentially dangerous chlorine, but also produces a large amount of calcium chloride-containing wastewater that pollutes the environment, both at home and abroad.

We are developing a new atom-economic reaction method for catalytic oxidation of propylene to propylene oxide.

For another example, EniChem uses titanium silicon molecular sieve catalyst to react cyclohexanone, ammonia, and hydrogen peroxide to directly synthesize cyclohexanone oxime.

Atomic economic reactions that have been applied in industry still need to be continuously researched and improved from the aspects of environmental protection and technical economy.

To achieve high atom economy of the reaction, it is necessary to develop new reaction pathways and replace stoichiometric reactions with catalytic reactions. The work of BCH Company, the winner of the New Synthesis Route Award in 1997, is a good example.