CS258827B1 - Oxygen Production Method O ((/ g)) - Google Patents

Abstract

A method of producing singlet oxygen O2 ?Δ9) by the reaction of chlorine with an alkaline solution of hydrogen peroxide in a bubbling generator, the essence of which is that gaseous chlorine is introduced into a layer of non-gasified alkaline peroxide solution with a height of 1 to 5 cm. Longer-term operation of the generator with a solution layer of the specified thickness can be ensured by continuous supply of an alkaline peroxide solution or simultaneous solutions of hydrogen peroxide and hydroxide and by removing part of it from the reaction space. The solution is particularly suitable for the preparation of singlet oxygen for an oxygen-iodine laser.

Description

The present invention relates to a process for the production of oxygen O ( ^X Ag) by reacting chlorine with alkaline solutions of hydrogen peroxide in a bubbling chemical generator. Singlet oxygen O, (£, g) is also used in chemical lasers based on the transfer of energy from the O ₂ (Ag) molecule to the iodine atom

O ₂ ( ^X Ag) + I ( ² P3 / 2> ---- i * I ^: P1 / 2) + ° 2 ⁽³ ^> U »

For this purpose, singlet oxygen is produced in chemical generators by the reaction of chlorine gas with alkaline solutions of hydrogen peroxide, the active component of which are perhydroxyl ions

Cl ₂ + HOj ---- Cl + HCl + O ₂ ( ^X Ag) (2)

The chemical detection of singlet oxygen directly in the liquid phase revealed that the yield of this reaction was practically 100% (G. N. Hays, G. A. Fisk: IEEE J. Quant. Electron.

QE-17, 1883 (1981)). However, most chemical generators produce singlet oxygen with significantly lower current yields.

For design simplicity and reliability, the most commonly used singlet oxygen generators are bubbling generators in which chlorine gas is introduced into the alkaline hydrogen peroxide solution at low partial pressure. Typical oxygen pressures in chemical generators of this type range from 40 to 400 Pa and singlet oxygen yields (percentage of O ₂ ( ^X Ag) to total oxygen) are typically 30 to 45%.

An analysis of the activity of the chemical generators has revealed that the relatively low yields of O ₂ ( ^X Ag) in the bubbling generators are due to the fact that chlorine gas is introduced under a layer of alkaline peroxide solution which is usually 7 to 8 cm high. the order of magnitude exceeding the working pressure in the gas phase of chemical generators. As a result, the diffusion path of chlorine and the resulting singlet oxygen from the gas-liquid interface is extended, thereby increasing the loss of singlet oxygen by inactivating it in solution.

Also, losses of singlet oxygen in the gas phase caused by the course of the reaction.

0 ₂ (g g) ---- Ο ₂ ( ^Χ g) + O ₂ ( ³ g) (3) are at the bottom. The bubbling chemical generator is approximately two orders of magnitude higher than above the solution due to hydrostatic pressure.

The above-mentioned disadvantages are greatly reduced by the solution according to the invention, which is concerned with a process for the preparation of an oxygen (III) by reacting chlorine with alkaline peroxide solutions in a bubbling generator. The principle of the invention consists in introducing chlorine gas into a layer of alkaline peroxide solution in the height of 1 to 5 cm. In order to ensure the long-term operation of the generator, it is expedient to have an alkaline peroxide solution continuously introduced into the reaction space and to remove part of the solution sq from the reaction space.

By using an ungassed solution layer of only 1 to 5 cm in height, the partial pressure of the reacting chlorine and the resulting oxygen is significantly reduced, thereby significantly reducing the losses of singlet oxygen in both the liquid and gaseous phases. Thus, the yields of singlet oxygen are increased to 60-80%.

The bubbling chemical singlet oxygen generator can be operated as a periodic one in which an alkaline peroxide solution is impregnated and then chlorine is introduced until the perhydroxyl ions in the solution are depleted. A more preferred solution is a continuous solution in which an alkaline solution of peroxide or simultaneously an aqueous solution of hydrogen peroxide and a hydroxide solution is continuously fed into the space in which the reaction with chlorine takes place and part of the solution is removed from this space.

This solution avoids the disadvantage of a small volume of reacting solution at a low solution height.

The importance of the invention lies in the fact that by increasing the yield of singlet oxygen, the power of the oxygen ion lasers using said generators is substantially increased.

E.g. increasing the singlet oxygen yield from 40 to 65% increases the laser power twice.

The process according to the invention and the effect it achieves are illustrated by the following results.

Example

Chlorine gas was introduced into the bubbling-type chemical generator at a rate of 0.4 mmol / s. The pressure in the gas space of the generator was 120 Pa. When changing the solution height in the generator, the yield of singlet oxygen in the gas stream measured at a location 2 m away from the generator varied according to the following table.

Table

Height of gas-free 130 108 86 43 21 solution (mm)

Yield 0 ( ^{* 1 2} g), 20 36 45 60 68 (%)

Claims (2)

A process for the production of oxygen (g) by reacting chlorine with an alkaline solution of hydrogen peroxide in a bubbler generator, comprising introducing chlorine gas into an alkaline solution of hydrogen peroxide, characterized in that the height of the bed of non-gasified alkaline hydrogen peroxide solution is within 1 to 5 cm. 2. A process according to claim 1, wherein the height of the layer in the range of 1 to 5 cm of alkaline hydrogen peroxide solution is given by the continuous supply of alkaline hydrogen peroxide solution or simultaneously by supply of hydrogen peroxide and hydroxide and removal of a portion of the spent solution from the reactor.