JPH03177313A - Device for producing boron trichloride - Google Patents

Abstract

PURPOSE:To continuously feed aluminum trichloride and boron trifluoride to advance reaction and obtain high-purity boron trichloride in high yield by provid ing a constitution in which aluminum trichloride and boron trifluoride do not exist as a solid phase in the same vessel of a device for subjecting aluminum trichloride to vapor phase reaction with boron trifluoride. CONSTITUTION:Metal aluminum mass is packed in a generator 2 of continuous generating device of aluminum trichloride consisting of a heater 1, generator 2, chloride introducing tube 2, aluminum supply port 4 and an aluminum trichlo ride flow tube 5 and preliminarily heated with the heater 1. Chloride and boron trifluoride are respectively fed from an introduce tube 3 into the generator 2 and from an introduce tube 7 into a pre-heated vapor phase reactor 6 each by a definite amount of continuously synthesize boron trichloride. The resultant boron trichloride is fed through an aluminum fluoride separator 8, low boiling point purifying tower 10 and high-boiling point purifying tower 11 into a storage tank 12. Aluminum fluoride is discharged through a discharge rotary valve 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a production apparatus for producing highly pure boron trichloride, which is used as a raw material for boron nitride production or as an etching agent for semiconductors.

[Prior art]

The conventional method for producing boron trichloride is J, 4m.

Chem, Soc, + vol. 62, p. 1257 (194
There is a method in which solid aluminum halide is reacted with boron trifluoride at a sublimation temperature, as described in ``Inoganikku Synthesis, Vol. 13, pp. 27-30.However, in this method, halogen are chlorine and bromine.In this method, aluminum trihalide is heated to its sublimation temperature and reacted with boron trichloride in the same container to obtain boron trihalide.

In this method, ↓ 0.5 mol of aluminum trichloride is sublimed, and a reaction using 2 mol of boron trifluoride, which is in large excess over the reaction equivalent, is carried out in the same container, and the yield per aluminum trichloride is 80. % of boron trichloride, but the yield per boron trichloride is extremely low at 20%. Using this method requires equipment for recovering or removing unreacted boron trifluoride. However, boron trifluoride is an extremely difficult gas to collect, and boron fluoride ions in the collection liquid are difficult to react with calcium ions, requiring special chemical treatment for wastewater treatment.

Due to the problems mentioned above, this reaction has not been used as an industrial method for producing boron trichloride to this day. After examining this reaction in detail from a divine perspective, the inventors discovered that the reason why it is not used in industrial production methods is as follows. In other words, since aluminum trichloride exists as a solid phase in the same container as boron trifluoride, the reaction progresses on the sublimation surface, and the reaction continues because the aluminum fluoride produced coats the solid surface. prevent.

[Problem 8 to be solved by the invention] The present invention enables the synthesis of high-yield, high-purity boron trichloride by continuously supplying aluminum trichloride and boron trifluoride in a gas phase to advance the reaction. The goal is to develop manufacturing equipment.

[Means to solve the problem]

The present inventors synthesized the gaseous aluminum trichloride of the generator by continuously feeding solid or molten aluminum with chlorine, hydrogen chloride, and/or a chlorine compound that reacts with aluminum, or We have developed an apparatus for producing boron trichloride by heating and sublimating aluminum chloride to generate gaseous aluminum trichloride, which is reacted with boron trifluoride in a gas phase reactor.

[Structure and operation of the invention]

The present invention relates to a manufacturing apparatus for synthesizing boron trichloride by continuously reacting aluminum trichloride and boron trifluoride in a gas phase. That is, a container filled with solid aluminum is heated, usually preferably to 180-600'C;
When passed through a chlorine compound that reacts with chlorine, hydrogen chloride, and/or aluminum, the reaction easily occurs, and aluminum trichloride is continuously generated as a gas at a reaction rate of approximately 100%. The reaction proceeds continuously by introducing this gas phase aluminum trichloride into a gas phase reactor consisting of a tubular empty column and introducing boron trifluoride from the other side. The reaction rate between the gas phases is extremely fast and the reaction yield is approximately 100%.

In the present invention, not only the embodiment in which vapor phase aluminum trichloride is produced by the above method and used as it is, but also the embodiment in which solid aluminum trichloride is sublimated to generate vapor phase aluminum trichloride is similarly applicable. It is.

The solid aluminum fluoride, which is a by-product of the reaction between the gaseous aluminum trichloride and boron trifluoride, is introduced into a separator located at the bottom of the tubular column that separates the gaseous and solid phases.

In this separator, boron trichloride and aluminum fluoride are
Cooled to 5-100'C. Solid aluminum fluoride is deposited at the bottom of the separator and is continuously discharged from the system by a continuous discharge device, such as a rotary pulp, to recover high-grade aluminum fluoride. The gas phase boron trichloride exiting the separator is continuously introduced into the condenser and liquefied. This crude boron trichloride is introduced into a distillation apparatus, and a trace amount of low-boiling substances such as HCI, BF, and CI are removed in a low-boiling point purification column, and further introduced into a high-boiling point purification column, FeC15,5iC1
Purify by removing high boiling point substances such as No. 4. It is also possible to purify crude boron trichloride by directly introducing the gas into a distillation apparatus without separating it.

As described above, the present invention continuously generates aluminum trichloride in the gas phase, reacts it with boron trifluoride in the gas phase, performs distillation purification, obtains high-purity boron trichloride, and removes the by-product fluoride. This is a series of continuous boron trichloride production equipment that recovers aluminium.

A typical example of an apparatus for carrying out the present invention is shown in FIG. Namely, heater (1), generator (2)
, a continuous aluminum trichloride generator consisting of a chlorine inlet pipe (3), an aluminum replenishment port (4) and an aluminum trichloride replenishment port (5), and a gas phase reactor for aluminum trichloride and boron trifluoride. (6), boron trifluoride inlet pipe (7), aluminum fluoride separator (8), aluminum fluoride discharge rotary valve (9), low boiling point purification tower 0
0), a high boiling point purification tower (11), and a storage tank 02).The materials used in this equipment are nickel and hastelloy metals, which are resistant to high-temperature chlorine, in the generator (2). It is preferable to use

Further, in order to prevent part of the aluminum from melting due to reaction heat and alloying with metal such as nickel, a support tube made of ceramic such as alumina can be incorporated between the aluminum lump and the metal material. Other parts are constructed of stainless steel.

In this apparatus, a column 03 filled with aluminum solid can be provided in the aluminum trichloride discharge pipe (5). As a result, even if unreacted chlorine remains due to the reaction between aluminum and chlorine, this remaining chlorine reacts with aluminum to become aluminum trichloride, and can be completely converted to aluminum trichloride.

Further, in the case of sublimating solid aluminum chloride in the present invention, aluminum trichloride may be heated and evaporated in the reactor (2) in the apparatus shown in FIG.

〔Example] The present invention will be explained in detail by giving examples below.

Example Aluminum chloride noblenium generator (2) Approximately 7 pieces of metal aluminum (approximately 50 g pieces) with an internal diameter of 300 mm and a length of 1000 mm
Fill with 0 kg and preheat to 200-400°C with a heater (+). Nickel gas phase reactor (6) is 200-40
Preheated to 0°C, inner diameter 52.5 mm, length 400 m
It consists of m tubular empty towers. The aluminum fluoride separator is air-cooled, and the condenser during distillation is cooled to 0-4°C with a refrigerant. Chlorine was supplied to the generator in (2), and boron trichloride was supplied to the gas phase reactor in (6) using a flowmeter controller, and the boron trichloride was continuously combined for 24 hours, as shown in Table 1. Boron trichloride was obtained in yields corresponding to the synthesis conditions shown and in the grades shown in Table 2, and aluminum fluoride was recovered in the grades shown in Table 3.

No. table Analytical value of boron trichloride produced No. table Analysis of recovered aluminum fluoride

[Brief explanation of drawings]

FIG. 1 is a drawing showing a typical example of the device of the present invention. ■... Heater 8... Aluminum fluoride 2... Generator Mu separator 3...
Chlorine introduction pipe 9...Rotary valve 4...
- Aluminum replenishment port 10... Purification tower 5... Aluminum trichloride 11... Purification tower outflow pipe
12... Storage tank 6... Gas phase reactor 13... Aluminum filling 7... Boron trifluoride column introduction tube (and above)

Claims (3)

[Claims] (1) An aluminum trichloride generating reactor, a reaction vessel for reacting gaseous aluminum trichloride and boron trifluoride in a gas phase, and a condenser for condensing the produced boron trichloride. Boron chloride production equipment. (2) High purity boron trichloride characterized by being equipped with an aluminum trichloride generating reactor, a reaction vessel for reacting gaseous aluminum trichloride and boron trifluoride in a gas phase, and a distillation device for distilling the reaction product. manufacturing equipment. (3) The aluminum trichloride generation reactor is a reactor that generates aluminum trichloride by reacting aluminum with chlorine and at least one chlorine compound that can react with aluminum, or is a reactor that generates aluminum trichloride, or solid aluminum chloride. The apparatus for producing boron trichloride according to claim 1 or 2, which is a reactor that generates aluminum trichloride by sublimating aluminum.