What is ketene
Vinyl ketone is a kind of organic compound. It is the simplest one. Its molecular formula is CH2 = C = O. it is a poisonous gas at room temperature. It is very unstable. It can only be preserved at low temperature. When it is at 0 ℃, it can polymerize to form dimer diethylene ketone. The two π bonds in vinyl ketone are in the form of orthogonal, and their chemical properties are very active. They can react with many substances containing active hydrogen. They are important intermediates in organic synthesis.
Preparation method of vinyl ketone
The common method of preparing vinyl ketone is to pass the acetone vapor into the pipe with the temperature of 650 ~ 800C, to make it decompose and produce vinyl ketone and methane. In the presence of trace triethyl phosphate, acetic acid can dehydrate to form ketene at a pressure of 100-400mm Hg and a temperature of 700-800 ℃. When the mixture of acetylene and oxygen (molar ratio 2:1) is kept at 98 ~ 107 ℃ and kept on ZnO / CaO / ago catalyst supported on silica gel for one second, vinyl ketone can be directly produced. Ketene is mainly used in the synthesis of chemical basic raw materials and reagents.
The liquid ring vacuum pump used in vinyl ketone production has the following advantages at least:
Liquid ring vacuum pump can operate continuously for a long time. Because transformer oil is used as circulation medium, transformer oil can not only produce oil ring to form vacuum and lubricate pump body, so liquid ring pump not only solves the problem that dry pump needs regular maintenance, but also can operate without fault for a long time due to the low failure rate of vulnerable parts of pump body itself;
The liquid ring vacuum pump is an isothermal compression process. Due to the extremely unstable nature of ketene, it greatly reduces the waste of materials. Whether it is a reciprocating pump or a slide valve pump, due to the temperature rise of gas during compression, a large number of substances such as diethylene ketone and acetic anhydride will be produced, and when the temperature is too high, a lot of Coke will be produced;
It is safer to use liquid ring vacuum pump for production. Because of the working principle of liquid ring vacuum pump itself, it will not have frequent cylinder flushing or cylinder leakage events like reciprocating pump, which greatly avoids the risk of cooling brine entering the system, and greatly reduces the sudden failure of vacuum pump, resulting in the sudden drop of system vacuum or even the leakage of vinyl ketone;
The use of liquid ring vacuum pump is more environmentally friendly, low noise and small pollution, without frequent maintenance, reducing the discharge of vinyl ketone.