What is dichloromethane?!

Association, expert group, gossip, running trains with mouth full

The agency, the third party, borrows the downhill donkey, and the eyes are smeared

This account has too much content about VOCs, and I have long been ashamed to talk about it. I will mention it again after being educated

1

Dichloromethane is a good thing

Dichloromethane (dichloromethane, Methylene Chloride, referred to as DCM, CAS RN 75-09-2) has the advantages of strong solubility and low toxicity, and is used in refrigerants, medicines, pesticides, adhesives, polyurethane foaming, cleaning, lithium battery separators, food additives and other fields. Dichloromethane has two production processes: natural gas chlorination method and chloromethane chlorination method. In 2021, our country's dichloromethane production is about 1.70 million tons, export 170,000 tons, and the market size is 4.60 billion yuan.

Dichloromethane is safe. It is one of the four chlorinated methanes. It has a slight aromatic odor, a high olfactory threshold of 522mg/m ³, and is less irritating. The melting point is -97 ° C, the boiling point is 39.8 ° C, and the saturated vapor pressure is 46.5kPa (20 ° C). Dichloromethane is non-flammable. The ignition temperature is 556 ° C, and the explosion limit is 14-22%. It can only form an explosive mixture when mixed with high concentration oxygen. It is a non-flammable low-boiling point solvent under normal conditions of use. It is often used to replace flammable petroleum ethers, ether, etc. It has excellent solubility to many resins, paraffins, and fats. It is one of the low-boiling point solvents with low toxicity and good non-flammability in industrial solvents.

Dichloromethane is low toxicity, which is the least toxic of methane chloride. Rats inhaled 4.69g/m ³ air for 8 hours a day for 75 days without pathological changes. The exposure time increased, with mild liver atrophy, steatosis and cell infiltration. The maximum allowable concentration of hazardous substances in the air of the workshop in the former Soviet Union is 50 mg/m ³. The national occupational health standard "Occupational exposure limits for hazardous factors in the workplace Chemical hazardous factors" (GBZ2.1-2007) stipulates: The time-weighted average allowable concentration of dichloromethane is 200mg/m ³ - refers to the average allowable exposure concentration of a normal 8-hour working day or 40-hour working week.

2

Dichloromethane is a bad thing

Dichloromethane is famous and "notorious". One of the first 10 high-priority substances for threat and risk assessment under the US Toxic Substances Control Act (TSCA). After evaluation, it was determined that the chemical is a neurotoxin and is acutely lethal and potentially carcinogenic.

Between 1989 and 2007, dichloromethane has caused 18 deaths and 56 injuries in the European Union. On 6 May 2009, the European Union Commission adopted Decision 455/2009/EC banning the use of paint strippers containing more than 0.1% dichloromethane from 6 December 2010.

On October 27, 2017, the World Health Organization's International Agency for Research on Cancer released a preliminary list of carcinogens for reference, and dichloromethane was listed as a carcinogen in category 2A.

In 2016, a dichloromethane death occurred in the United States. The incident began when a temporary worker, while removing the coating of a bathtub in a residential bathroom, poured paint remover containing 85-90% dichloromethane into the bathtub and began scraping. The only ventilation was a partially open window. Two hours later, the apartment occupant found the worker unconscious and collapsed on the bathtub, and finally died. Since 1980, at least 85 people have died from acute exposure to dichloromethane, the E.P.A. says, most of them workers working in home improvement contracting jobs, and in some cases, they were even fully trained and equipped with personal protective equipment. Many others have experienced severe and long-term health effects, including certain cancers. On March 27, 2019, the U.S. Environmental Protection Agency (EPA) announced the latest regulations banning the production (including import), processing and addition of dichloromethane, and the use of dichloromethane in paints and paint strippers, effective November 22, 2019.

In our country, the "Industrial Structure Adjustment Guidance Catalogue" (2011 edition) began to stipulate that "paint strippers containing benzene, phenol, benzaldehyde and bis (tri) chloromethane" are "backward products".

On January 23, 2019, dichloromethane was added to the list of toxic and hazardous air pollutants (2018)

On July 23, 2019, dichloromethane was added to the list of toxic and harmful water pollutants (first batch)

The "List of Key Control New Pollutants (2023 Edition) " prohibits the production of paint strippers containing dichloromethane, and it will be explicitly banned when opinions are solicited in 2021.

3

Dichloromethane is not a thing

Dichloromethane is not a WHO VOCs

Volatile organic compounds, commonly expressed as VOCs. According to the definition of the World Health Organization (WHO), VOCs are various organic compounds with a boiling point of 50 ° C to 260 ° C at room temperature. Dichloromethane is a low-boiling solvent with good non-flammability. The boiling point is only 39.8 ° C and less than 50 ° C. It may be gaseous at room temperature.

There are two methods for the detection of volatile organic compounds, TVOC and NMHC. I don't know which method can detect it. A fixed source emits 1100 tons per year. The NMHC automatic detection concentration of non-methane total hydrocarbons on site is very low, and the smell is also very light. It looks very efficient and environmentally friendly...

Dichloromethane Sphinx

Dichloromethane is a product of chlorinated oxidation of methane, semi-oxidation is non-flammable, has the "tetrahedral" appearance of methane, is a long-lived gaseous pollutant, and has a greenhouse effect similar to methane;

Dichloromethane also contains two chlorines, which can destroy the ozone layer. It is malignant with chlorine of Freon and Dioxin.

Dichloromethane is the first batch of "toxic and harmful air pollutants" and "toxic and harmful water pollutants" in our country.

Dichloromethane is the new favorite of the Japanese, the favorite

As mentioned earlier, Europe and the United States cannot bypass Japan. The Japanese are very smart and often have to take it. For example, the application of DCM, NMP (N-methylpyrrolidone CHNO), IPA (isopropanol), ethanol, etc. in industrial production is perfect, and sometimes I sigh at their wisdom.

Europe and the United States banned dichloromethane as paint and paint removal, our country followed suit, Japan? What will the Japanese do?

They would do something like this:

4

Dichloromethane is a magic mirror, an expert grinder

In a Japanese-funded factory in South China, the production of photosensitive drums includes coating and cleaning (paint removal), cleaning high-precision aluminum tubes into coating cylinders, coating photosensitive chemicals (containing methanol, dichloromethane, and dichloroethane solvents), removing them with dichloromethane solvent to remove excess coatings, heating and drying in a closed space, drying exhaust gas condensation recovery solvent, non-condensing activated carbon adsorption concentration desorption regeneration and recovery, in 2016, the actual purchase and use of 1,100 tons of dichloromethane that is, the emission of 1,100 tons of dichloromethane, and the 2017 VOCs comprehensive management expert review/verification was passed. When the municipal bureau leaders reviewed the summary materials, they found this "behemoth".

In-depth governance in 2022, paper emission reduction, reported emissions of 138.912 tons in 2021, and everyone is happy to complete the task.

The snake must be added eventually. In September 2022, the Division's "VOCs Deep Treatment Plan" Annex 5 is "Expert Opinions on the Irreplaceability of Coating Organic Solvents (DCM) ". "China" experts do not understand the relevant policies. "Wang Gu said right and wrong," the national standard of the group standard "has not put forward a ban on dichloromethane," and the conclusion that "based on the above, the dichloromethane currently used in the production process of OPC photosensitive drums is irreplaceable".

The "turtle expert" was seen by the "civil servants" looking for teeth all over the place, and must continue to upgrade the tiger skin as a banner. With this "irreplaceable" expert opinion of the "country" prefix, Japanese-funded factories can continue to run amok in Greater China.

Officials who engage in "deep governance" according to the services of third parties, although there is no way and no breakthrough point, as long as they have achievements, they will have the inside and face, and they can just borrow the donkey from the slope, and everyone is happy!

Association expert group, gossip, mouth full of trains

The third party of the agency borrows the donkey from the slope, and the eyes are smeared

What exactly is dichloromethane?!

A small dichloromethane, like a ghost, a human sphinx, and a mirror shredder...

When encountering dichloromethane, all experts dissolve it, all appear in their original form, and they will pay it back when they come out to mix