JPS6155190A - Refining of tar acid - Google Patents

Abstract

PURPOSE:To easily remove high-boiling heterocyclic compounds contained in a tar acid to refine it, by distilling the tar acid with sulfuric acid, an organic sulfuric acid derivative or a sulfonic acid derivative added to it. CONSTITUTION:Sulfuric acid, an organic sulfuric acid derivative or a sulfonic acid derivative is added to a tar acid, and the obtained mixture is subjected to distillation. The aforementioned tar acid refers to a tar acid which comprises a crude tar acid obtained by the neutralization and decomposition of a sodium salt of a tar acid with an acid, a refined tar acid obtained by the dehydration of and/or pitch removal from a crude tar acid, and phenol, o-cresol, m-cresol, p-cresol, xylenol, etc. obtained by the distillation of a refined tar acid, and contains basic nitrogen compounds. The acid or acid derivative is added in an amount at least equivalent to that of the tar base contained in the tar acid. The distillation temperature is preferably as low as possible; practically, distillation at a temperature at the bottom of a tower of 200 deg.C or lower under ordinary pressures or reduced pressure is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for purifying tar acid produced as a by-product from coal carbonization or coal gasification processes.

Tar acid is originally a phenol and cresol.

This is a general term for xylenols, but the tar acid contains aniline, pyridine, which is generally called tar base,
It contains basic nitrogen compounds such as phosphorus, lutidine, and quinoline and other impurities and is used as an image side, but when used as a raw material for synthetic resins and plasticizers, the above impurities are removed as much as possible. must be removed. Furthermore, for resource reasons, the source of materials for synthetic resins and the like has recently been replaced by coal-based materials rather than petroleum-based ones, so the development of a tar acid purification method has become a major issue.

[Conventional technology]

Conventionally, in order to obtain tar acid from the coal carbonization process, the raw material tar light oil, carpol oil, naphthalene oil or absorption oil is washed with a dilute caustic soda aqueous solution, thereby converting the tar acid in the raw material into its soda salt. Then, after removing the neutral oil and tar base by steaming or light oil washing, neutralization and decomposition are performed using sulfuric acid or carbon dioxide, and if necessary, other methods such as distillation are used. .

However, in the above method, relatively low boiling point bases such as pyridine are easily removed in the steaming process, but high boiling point bases such as aniline are difficult to remove. This is not desirable from an economic point of view.

[Eight Points to be Solved by the Invention] From the above viewpoint, the present invention provides a purification method for easily reducing aromatic amines and high-boiling heterocyclic compounds such as lutidine.

[Means for solving problems]

The present inventors have discovered that the above problems can be solved by adding sulfuric acid, an organic sulfuric acid derivative, or a sulfonic acid derivative to tar acid and subjecting the mixture to distillation.

The tar acid referred to in the present invention refers to crude tar acid after neutralization and decomposition of sodium tar acid salt with an acid as described in the conventional method, purified tar acid obtained by dehydrating and/or depitching crude tar acid, and purified tar. 7E/-Rou0- obtained by distilling acid
Cresol, iso-p-cresol, xylenol, etc. In other words, it refers to tar acid containing basic nitrogen compounds.

The sulfuric acid added to such tar acid is generally laurylbenzenesulfone M t P-pheno-/I/
/I/ 7 oz. organic sulfonic acid or sulfone intoxicant salt.

The amount of sulfuric acid, organic sulfuric acid or sulfonic acid derivative added is equivalent to or more than the amount of tar base, particularly basic nitrogen-containing compound, contained in tar acid.

After adding to tar acid, stir well and distillation can be started immediately. During distillation, the tar base reacts with the added sulfuric acid or the derivatives mentioned in (1) and (2) above at the distillation temperature to form high-boiling salts, which can be distilled into a pitch-like pot without distillation. It is removed as a residue.

The removal of tar bases according to the present invention takes advantage of the fact that additives and bases form salts that result in high boiling points or high decomposition temperatures. For this reason, it is desirable that the distillation temperature be as low as possible, but in practice it is preferable to distill at a bottom temperature of 200° C. or less under normal pressure or reduced pressure.

[Comparative example]

200 g of crude tar acid having the composition listed in Table 1 was added to
Charged to a flask with 0 g/g/ml, and the bottom temperature was 180°C under normal pressure.
Dehydration was carried out using a distillation column with 15 theoretical plates. That is, first, 33.5 g of water and oil were distilled from the top of the column.

Table 1 The oil component is phenol, etc., which is azeotropically distilled with water.

Then, the mixture was subjected to vacuum distillation while maintaining the bottom temperature at 180'C to reach a final pressure of 30 mHg. Pitch-like pot residue IQ remained in the flask, and 144y of dehydrated and depitched tar acid, in other words purified tar acid, made a loud noise. Note that the loss was 8.5 f.

〔Example〕

To the crude tar acid listed in Table 1, add concentrated sulfuric acid, sulfuric acid derivative, or sulfonic acid derivative in an amount equivalent to twice the basic nitrogen compound contained therein, and perform the same operation as in the above comparative example to distill purified tar acid. did. The material balance itself is not substantially different from that of the comparative example.

The types and contents of basic nitrogen compounds in the distilled purified tar acid, including the raw material crude tar acid, are listed in Table 2 (in W/kq).

Table 2 As shown in Table 2, by adding concentrated sulfuric acid or lauryl sulfate sulfonic acid derivatives and distilling it, most nitrogen cyclic compounds such as pyridine and aromatic amine compounds such as aniline can be removed. All the tar bases are removed as a pitch-like residue, and the dehydrated and depitched tar acid, that is, the purified tar acid, contains almost no tar bases.

〔Effect of the invention〕

As detailed above, according to the method of the present invention, substantially all of the basic nitrogen compounds in tar acid can be removed by the simple operation of adding a small amount of sulfuric acid or its derivatives or sulfonic acid derivatives and distilling the mixture. ; It was possible to remove it. For your reference, when sulfuric acid is added, it is thought that in addition to forming a salt with the tar base, sulfonated products with tar acid are also formed.

Claims (1)

[Claims] 1) A method for purifying tar acid, which comprises adding sulfuric acid, an organic sulfuric acid derivative, or a sulfonic acid derivative to tar acid and subjecting it to distillation. The amount added is equivalent to or more than the tar base contained in tar acid.Claim 1) The method according to claim 1)The distillation is distillation at a bottom temperature of 200°C or lessClaim 1); 2) Method of description