DE1567484C - Process for the one-step production of chlorine and sulfuric acid - Google Patents

Description

1 567 4B4

Liquid detected in the empty condenser at the exit of the furnace. The results are in the following Table I compiled for a contact time of 3 seconds.

Table I.

Before the catalysis oven After the catalysis oven and after absorption

450C 480C

500 C

510'C

gMol / h ......!

HCl,% ..

g mol / hour

Cl ₂ ,%

gMol / hr ....

Yield,

based on the HCl used

based on SO ₃

8.6 0.457

12.9 0.674

0.28 0.013

6.1

0.243

72% 97.2% 0.32 .:
0.015

sense

6.6
0.266

78.9%
96.8%

0.34
0.0155

6.4
0.256

76.1%
96.6%

0.35 0.016

6.3

0.252

74.6% 96.5%

It should be noted that there is no longer any HCl present in the exit gas. The hydrochloric acid that has not been converted to chlorine is in the form of condensed HSO ₃ Cl. The chemical analysis of the condensate after the catalytic furnace corresponds to an acid, the density of which fluctuates from 1.78 to 1.80, including most of the unreacted HCl in the form of HSO ₃ Cl and part of the

Table II

SO ₂ + O ₂ + 2 HCl

H ₂ SO ₄ + Cl ₂

sulfuric acid formed. Part of this acid is _{condensed with the HSO 3} CI, the other part is retained in the absorber.

35

Example 2

40

: The same gas mixture as in Example 1 was used, but a device was added to the apparatus in order _{to condense the HSO 3} Cl formed more effectively and to add a suitable amount of water (4 to 5 g / hour under the test conditions) to this liquid. The air used, to which the _{water required for the decomposition of HSO 3} Cl was added in the form of steam, flowed through a space which was sprinkled with condensate in the upper part. The hydrochloric acid formed by the decomposition of the HSO ₃ Cl was taken away from the Luff, to which the starting gases SO ₂ (101 / hour) and HCl (15 1 / hour) were then added.

The analyzes were carried out under the conditions mentioned in Example 1 (by gas-liquid chromatography) performed.

Concentrated sulfuric acid (96 to 97%) was taken off at the foot of the column in which the HSO _{3 Cl was decomposed.} This acid containing virtually no more HCl (content below 0.1%).

The results for the conversion of HCl to chlorine are given in Tables below for a contact time of slightly less than 3 seconds. The analyzes of the gas mixture before the reaction show that about 20 to 30% of the original HCl was circulated. SO ₂ , percent by volume ..
g mol / hour ..........

HCl, percent by volume.

g mol / hour

Chlorine, percent by volume

g mol / hour

yield

% HCl

% SO ₂ ..

Before the
Catalysis furnace

8.6
0.457

12.9
0.674

After the catalytic furnace, decomposition of HSO ₃ Cl and absorption

460 C

0.38 0.0162

480 ^ C

0.44 0.018

Indeterminable traces

8 0.32

94.9 94.5

8.2 0.326

96.8 94

It was also found that the unconverted hydrochloric acid is not completely in the Acid was located, which was withdrawn from the device, in which the decomposition of the chlorosulfonic acid was made. Part of the chlorosulfonic acid is therefore not condensed and with the sulfuric anhydride held in the absorber.

Claims (6)

Patent claims: 1. Process for the one-step production of Chlorine and sulfuric acid by the simultaneous oxidation of hydrochloric acid and sulfur dioxide in the presence of a vanadium-containing oxidation catalyst, characterized in that one is essentially off Gas mixture consisting of sulfur dioxide, hydrochloric acid and an oxygen-containing gas, in which the concentration of sulfur dioxide is slightly more than 1 mole per 2 moles of hydrochloric acid is, at temperatures in the range between 400 and 600C, preferably at normal pressure with a catalyst made of vanadium compounds and alkali and / or hard alkali Stalls and / or their oxides insists on an inert iiger, brings into contact, the gaseous product, which also contains small amounts of sulfur dioxide as well as chlorine and sulfuric acid hydride, cools and thereby liquefies sulfuric acid id chlorosulphonic acid, separates the chlorosulphonic acid and absorbs the sulfuric anhydride in the sulfuric acid and the gaseous chlorine wins. ^: ■. · - ■ · ■ .. ■■■ ·. '· .- ■■ -'^; - ^r '■' ■■■■ 2. The method according to claim 1, characterized in that a catalyst is used which contains 3 to 15 percent by weight of vanadium, calculated as V ₂ O ₅ . 3. Process according to Claim 1 or 2, characterized in that a catalyst is used which, in addition to vanadium pentoxide, also contains 5 to 20 percent by weight of alkali metal oxides, calculated as K ₂ O. 4. The method according to claim 1 to 3, characterized in that the gas mixture 1 to 20 seconds, preferably 3 to 10 seconds, brought into contact with the catalyst. 5. The method according to claim 1 to 4, characterized in that the sulfur dioxide in gaseous starting mixture partially replaced by sulfuric anhydride. 6. The method according to claim 1 to 5, characterized in that the separated chlorosulfonic acid is decomposed with water, the hydrochloric acid formed in the process is returned to the starting mixture and the SO ₃ formed is removed in the form of sulfuric acid. 109 6Λ7 151