Boron trifluoride is an important catalyst widely used in organic synthesis and petrochemical industry. It is widely used in many organic chemical reactions such as alkylation, polymerization, isomerization, addition, synthesis and decomposition. The reason why it has such a wide range of applications in catalytic reactions is that the boron electron layer structure has a strong tendency to form complexes, which is very important to produce catalytically active structures in acidic catalysis. In many reactions, boron trifluoride based catalysts are more active than inorganic acid metal halide catalysts without causing adverse side reactions. As a catalyst, BF3 can be used in various forms, such as in gaseous form alone, or in combination with many types of inorganic and organic additives and in its complex application. At the same time, it can be recycled by distillation or chemical methods, and reused by refining. BF3 and its compounds are used as curing agents in epoxy resins, and are also widely used in the dyeing of polymerase fibers and the manufacture of alcohol-soluble phenolic resins.

1. Catalysts for organic synthesis

BF3 plays a catalytic role in many organic synthesis. For example, in the industrial production of medium molecular weight PIB, BF3 catalytic system can not only simplify the production device, shorten the production cycle, reduce the labor intensity, but also significantly improve the yield of PIB.

2. Ion boronizing

The term "boronizing" first appeared in the literature in 1917, but detailed information about the boronizing treatment and the characteristics of the boronizing layer did not appear until more than 50 years later. Boronizing, or boronization, is an austenite chemical heat treatment applied to black and non-ferrous metal materials to form a hardened layer containing boride on the surface. The hardness of boronizing layer is up to 2000HV, and it has good wear resistance and corrosion resistance. Because boron trifluoride is easier to operate, does not need to be heated on the gas path, it is more evenly distributed in the furnace, and because of its high boron content, it is often used as the carrier gas of boron in ionizing boronizing.

3. Used as rapid curing agent at room temperature

BF3 is a rapid curing agent for epoxy resin at room temperature. BF3 as curing agent should be packaged separately from epoxy resin and should be used as required. During operation, the ratio error affects the bonding quality and the process is complicated. At present, BF3 is made into micro capsules by selecting solid substances with different melting points as wrapping materials, and the interaction between epoxy resin and BF3 is blocked by the capsule wall, so that a single component product can be made and stably stored. The release temperature is selected by the melting point of the capsule material, at which BF3 curing agent is released from the capsule material, which is mixed with the epoxy resin to promote its rapid curing. The flexibility of cured epoxy resin can be improved by selecting the viscosity and molecular chain length of the capsule material.

4. Application in the field of nuclear technology

Trimethyl borate was formed by the reaction of boron trifluoride -10- ether complex with calcium chloride, and then hydrolyzed. After steam concentration, the high purity borate obtained could be used as neutron moderator in nuclear reactors.

Certain complexes of BF3 enrich 10B in the form of 10 BF3, which can be used to separate boron isotopes. 10BF3 can be used as a neutron absorption medium in the proportional neutron counter in nuclear technology and for the control of nuclear reactors.

5. Ion implantation source for semiconductor device manufacturing process

Boron trifluoride is used as ion implantation source in semiconductor device manufacturing process, which can improve the performance of semi-allogenic devices.

When a group V atom is doped into a crystal of group IV silicon atoms in the periodic table, it can conduct electricity due to the extra free electron in the outer shell. We refer to the group V impurity as the N-type impurity and to the atom that generates the free electron as the donor. When group III atoms are doped, in contrast to the above situation, holes appear due to the lack of an electron. In this hole, neighboring electrons can jump in and can move in sequence. This group III impurity is called a P-type impurity, and the atom that produces the hole is called the acceptor.

Typically, phosphorus and arsenic are used as N-type impurities and boron as P-type impurities. This impurity is called a dopant, and the process of adding a dopant is called a dopant. Usually, the doping ratio is 106-107 silicon atoms doped with 1 impurity to form a conductive region.

Methods of doping include thermal diffusion and ion implantation. Thermal diffusion method is to put the silicon wafer in a diffusion furnace, heated to about 1000℃ in the impurity gas temperament, then the impurity atoms will diffuse into the silicon crystal, thus forming a conductive zone. The gases commonly used in the thermal diffusion method are ethylborane (B2H6) for the P-type and phosphine (PH3) and hydrogen arsenide (AsH3) for the N-type.

Ion implantation is a technique that ionizes impurity atoms in a vacuum, accelerates them in an electric field, and then drives the ions into the crystal. The gases used in ion implantation are boron trichloride (BF3), phosphine and hydrogen arsenide. Ion implantation is less affected by impurities because it has an internal mass analyzer to select the required ions. In addition, the amount of ion implantation can be controlled by electric field adjustment, and the concentration and position of ion implantation can be adjusted, so it is superior to the thermal diffusion method.

6. Metallurgy and welding

BF3 can prevent the oxidation of magnesium and its alloys in molten casting, and is used as a flux in welding magnesium. It is also used as a component of surface boronization treatment agent for steel or other metals, and as a lubricant for cast steel. In the arc welding of titanium, if BF3 is involved, the weld will have strong impact resistance.

7. Synthesis of ethborane

Boranes can be prepared from BF3. It reacts with alkali metal hydrides to form ethoborane. Reaction with Grignard reagent yields organoborides

8. Medical treatment

With technological advances in the medical field, new antibiotic drugs are constantly being developed. The synthesis process of these new antibiotic drugs requires boron trifluoride gas as a catalyst.