DE582044C - Process for the production of practically sulfur-free phenolate liquor - Google Patents

Description

Process for obtaining practically sulfur-free phenolate lye. Recently the phenol content of the ammonia water accumulating in the coking plants is to a large extent made usable. The ammonia water is washed with benzene for this purpose to transfer the phenols into benzene. This phenol-containing benzene then becomes the phenols are removed by washing with caustic soda and further processing fed to pure products.

It has been shown that the phenolate liquor produced in this way is very heavily contaminated by sulfur compounds that come from the ammonia water come; the extraction of the pure products from the phenolate in the presence of sulfur but is associated with considerable difficulties, so that z. B. a phenolate liquor, in which more than 50% of the total alkali is bound to sulfur, for further processing is not to be depreciated on phenols. Immediately with the washing out of the phenols Caustic soda, at the same time all impurities, such as hydrogen sulfide, Carbon disulfide, cyano compounds and the like are included, but the permissible maximum limit on total sulfur always exceeded, so that it is necessary is to remove the sulfur from the phenol-containing solution before treatment with sodium hydroxide solution To get benzene out to get a phenolate liquor, its further processing on pure phenols is not disturbed by the presence of sulfur compounds. It has now been found that it is advantageous to use the sulfur-contaminated phenol-containing Benzene can be pre-cleaned by washing with sodium carbonate solution before the phenols be extracted with caustic soda.

The liberation of the phenolic benzene from the sulfur compounds, without taking out phenol at the same time, sodium carbonate solution is used reached smoothly. This was not to be expected without further ado, for it was known that Sodium carbonate solution dissolves phenols; On the other hand, it was probably also known that the phenols can only be resolved slowly. But it was not known that in the presence of hydrogen sulfide practically no phenols at all go into the sodium carbonate solution. On the contrary, it sodium sulfide solutions had been found to dissolve phenols. That's why it was assume that as a result of the uptake of hydrogen sulfide by the. Sodium carbonate solution the ability of the carbonate solution to dissolve phenols that are present in small amounts is, would be reinforced. But that this is not the case, but the opposite, enables the present procedure to be carried out. Attempt = it will be ok kg of phenol-benzene with 0.2% phenol with 100 g of 10% sodium carbonate solution Treated at room temperature. After allowing the sodium carbonate solution to settle and draw off will the phenols were washed out of the phenol-benzene with 60 g of 20% sodium hydroxide solution. After settling, the phenolate is drawn off.

The sulfur content of the phenolate liquor is 0.2% of what is present Sodium hydroxide calculated. In the sodium carbonate solution, 40 mg of phenol, the are o, 2 0, f. of the phenol present. Experiment 2 As above, 10 kg Phenol-benzene treated immediately with 60 g of a 20% sodium hydroxide solution. After sitting down the phenolate is drawn off.

The sulfur content of the phenolate based on sodium hydroxide present calculated is 7.3%. Experiment 3 10 kg of benzene, hydrogen sulfide by sodium hydroxide solution and phenol are free, are given an addition of o.200 pure phenol-cresol and are then with ioo. g pure = o above sodium carbonate solution treated. After this Remove zoo mg phenol = 10 /, of the existing in the sodium carbonate solution Phenol found.

From these experiments it appears i. that the removal of the impurities by the sodium carbonate solution means that the phenolate liquor obtained afterwards is largely free of sulfur (experiment i against 9,); 2. that by treating the phenol-benzene with sodium carbonate solution in the presence of hydrogen sulfide, practically no phenols go into the sodium carbonate solution (experiment i versus 3).

The present procedure has the advantage over other processes that the sodium carbonate solution used for desulphurization can be regenerated very easily by heating or passing gases through. EXAMPLE The process can be carried out on a large scale as follows: The phenol-benzene contaminated by sulfur compounds runs through line a to a roller pump b; Before the pump, 100% sodium carbonate solution is added to the benzene through a funnel. When passing through the pump, the benzene and carbonate solution are thoroughly mixed and the benzene is largely desulphurized. The benzene carbonate mixture is then pressed up through the line d into the separating vessel s, in which the sodium carbonate solution separates from the benzene. The desulphurized benzene flows off through c, the carbonate solution through l to the pan P, in which it is regenerated by heating to 70 to 80 °. The pan P includes the column k and the cooler v, which have the purpose of recovering benzene that has been entrained by the sodium carbonate solution.

The effect of the procedure is indicated by the numbers below: Sulfur content of the benzene before entering the desulphurizer 62 mg / l, Sulfur content of the benzene after leaving the desulfurization apparatus o, 2 mgfl, sulfur content of the phenolate liquor 0.0404.

Claims (1)

PATENT CLAIM: - Process for obtaining practically sulfur-free phenolate liquor from sulfur compounds and benzene containing phenols, characterized in that the benzene is first treated with sodium carbonate solution and then in a known manner with sodium hydroxide solution: