Dichloromethane is mainly used in film production and medicine in China. Among them, the consumption for film production accounts for 50 percent of the total consumption, the pharmaceutical industry accounts for 20 percent of the total consumption, the detergent and chemical industry accounts for 20 percent of the total consumption, and other aspects account for 10 percent. Industrial dichloromethane is generally prepared by reaction of natural gas and chlorine gas. It is an excellent organic solvent and is often used to replace flammable products (such as petroleum ether and diethyl ether). In addition, because the toxicity is very small, and the recovery after poisoning is faster, so it can be used as an anesthetic.

     The physical and chemical properties
     Dichloromethane is a compound formed by replacing two hydrogen atoms in methane molecule with chlorine. The molecular formula is CH2Cl2, and the molecular weight is 84.93. Colorless, transparent, volatile liquid having an ether-like odor and sweet taste. Insoluble in water, soluble in ethanol and ether. Is a non-flammable low boiling point solvent, commonly used in place of flammable petroleum ether, ether, etc. Dichloromethane is slightly soluble in water, and most commonly used organic solvents are mutually soluble, and other chlorine-containing solvents, diethyl ether, ethanol can also be miscible in any proportion. Dichloromethane can be quickly dissolved in phenol, aldehyde, ketone, glacial acetic acid. Pure methylene chloride without flash point, methylene chloride and gasoline containing such as volume, solvent naphtha or toluene solvent mixtures is non-flammable, however, when the methylene chloride and acetone or methanol liquid to 10:1, mixing ratio, the mixture has a flash point, vapor and air form explosive mixture, explosion limit of 6.2% ~ 15.0% (volume). Dichloromethane is the least toxic of methane chlorides, and its toxicity is only 0.11% of carbon tetrachloride toxicity.

     Here, to highlight the point, we all know that chlorine-containing compounds are generally toxic, our methylene chloride is also. Although it has been mentioned above that methylene chloride is the least toxic of methane chlorides, but if the human body accidentally exposed to it, how should we deal with and prevent?

     When the human body is exposed to methylene chloride, it will generally have the following symptoms:
The vapour of dichloromethane is anesthetic, a large number of inhalation can cause acute poisoning, nasal pain, headache, vomiting and other symptoms. Chronic intoxication may cause dizziness, fatigue, loss of appetite, impaired hematopoietic function and decreased red blood cells. If methylene chloride is splashed directly into the eye, it is painful and corrosive. Exposure to very high concentrations can lead to loss of consciousness and death.

Preventive measures:
A direct gas mask (half mask) should be worn when the concentration of dichloromethane in the air exceeds the standard. In case of emergency rescue or evacuation, wear air breathing apparatus.

First aid measures
In case of skin contact, immediately remove contaminated clothing and thoroughly rinse skin with soapy water and clean water; Eye contact: Lift eyelid, rinse with running water or normal saline. Other circumstances are not described in this paper.

On the nature of methylene chloride and so on is briefly introduced here, then take you to look at the methylene chloride as a chemical commodity in the industry some of the situation

Price movements over the years
From the price chart over the years, it is not difficult to find that methylene chloride has experienced a change from high to low, and then a small rise from the low, and then all the way up. From October 2015 to March 2016, the price of methylene chloride was low and kept falling. Mainly because of the rapid growth of capacity, but downstream demand did not rise as promised. An increase in spare capacity is the main reason for the fall in prices. The production capacity of methylene chloride increased, but the growth rate of production and apparent consumption did not achieve the synchronous growth, the oversupply situation is more prominent.

Since 18 years ago, the excess capacity has been gradually consumed, the price trend is relatively stable, and the overall trend is on the rise. Mainly related to equipment maintenance and supply contraction of some manufacturers. At the same time, the downstream industry product price is high, the acceptance of methylene chloride manufacturers to raise the price is still there, and the arrival of summer to promote refrigerant into the sales season, but also for raw material methylene chloride price to provide support. In addition, in the environment of blue sky protection, chemical raw materials can be said to be "rare things are expensive", and most chemical raw materials rise with the tide, which is also one of the reasons for the rise of methylene chloride price.

Market supply and demand
      At present, the supply and demand of methylene chloride in the world are basically balanced, but due to the unbalanced development between products and countries and regions, the increase and decrease of its future production also varies from region to region. Because the United States, Western Europe, Japan successively exports some environmental protection laws and regulations, strictly control the emission, recycle as much as possible, the United States and other developed countries and regions consumption is expected to decline year by year, and other countries and regions of the world, such as eastern Europe, the Middle East, Asia and Latin America and the developing countries to the demand of methylene chloride will maintain rapid growth