CS201715B1 - Process for the isolation of anhydrous non-aromatic aminoxides - Google Patents

Description

The invention relates to a process for the isolation of anhydrous non-atonatic amine oxides of the general formula

Γ'I - R, where R stands for an aliphatic chain with carbon numbers 1 and 18 and X denotes (CHg),, (CHg) _g , (CHg) g CH (CHg) _T , (CHgCHglgO, (CHgCHglgNlOjR), where R has The non-aromatic amine oxides that are currently manufactured industrially are prepared for use as more or less concentrated aqueous solutions (20 to 50%), which are closely related to their method of preparation.

It is then difficult to isolate the pure, anhydrous active substance required for certain purposes (determination of physical constants, physicochemical properties, analytical purposes, etc.) from these solutions (due to the excellent surfactant properties of the amine oxides). This disadvantage, withdrawn by isolation from aqueous solutions, is eliminated by the process according to the invention, whereby anhydrous amine oxide can be isolated from the aqueous solution by azeotropic distillation with dry benzene, a mixture of dry benzene and dry ethanol (1: 1) or with dry toluene. remove crystalline bound water.

The meted isolation was proved also in those amine oxides, commonly meted could not get rid of the water and also in those in which the crystalline bound water remained in the molecule, and the eušcní TO VétaíOYOe OMÍkátore of Ρ ^ Ο ^ θ F ^or 13 pascal, optionally, crystalline water could not be removed either by drying at 100 ° C above P 2 O 4 and at a pressure of 1.6 kPa, nor by freeze-drying.

To illustrate this method, examples are given which are generally valid for each of the above compounds.

Example 1

From the reaction mixture, which after oxidation contains 37 g of NN * -dinonylpiperazine-N, N'-dioxide, 30 ml of methanol and about 50 g of water, after distilling off water and solvent at 50 ° C and vacuum of 1.6 kPa, followed by several times Crystallization from anhydrous solvents gives the product as the dihydrate, mp 190-101 ° C, elemental analysis (calculated / found%): 064.98 / 05.05; 8 = 12.39 / 12.26; N = 6.89 / 7.00. Infrared spectroscopy: characteristic Wide intonative band of valence vibration (OH) with a maximum in the region of 3400 cm ¹ 'and a wide band of low strain vibration intensity ((0H) in the region of 1600 cm ¹ .

The presence of water was also confirmed by ¹ H-NMR spectroscopy. The quantitative amount of crystalline water was determined by thermogravimetry. However, when the solvent was distilled off after completion of the reaction, dry benzene was added to the reaction mixture, optionally a 1: 1 dry benzene / dry ethanol mixture and distilled off at 50 ° C and 1.6 kPa (this procedure was repeated five times with 50 ml of drying solution each time) to give an anhydrous product, mp 185-186 ° C; elemental analysis (calculated / found X): C = T 1.30 / 71.22; H, 12.51 / 12.49; N = 7.56 / 7.60.

No bands characteristic of the presence of water were observed in the infrared spectra, nor were the signals pertaining to the hydrogen atoms of the water molecules observed in the ¹ H-NMR spectra.

Example 2

The procedure is similar to Example 1, instead of N, N'-dinonylpiperazine-N, N'-dioxide was treated with 4-propylmorpholine-N-oxide, which after evaporation of the solvent was a colorless oil. Dry toluene (5x50 ml) was used for drying and after drying and isolation an anhydrous product of 8 m.p. 143-146 ° C, elemental analysis (calculated / found X): 0 = 57.90 / 57.61; 8 = 10.41 / 10.53; N = 9.65 / 9.62.

Spectral records (IR, NUR) showed the absence of water.

Example 3

The procedure is similar to that of Example 1, but 1-tetradecylperhydroazocine N-oxide, which was a colorless oil after evaporation of the solvent, was treated. Dry benzene (5x50 ml) was used for drying aa and after drying and isolation an anhydrous product was obtained with m.p. 115-116 ° C, elemental analysis (calculated / found X): 0 = 77.47 / 77.32; 8 = 13.31 / 13.57; N = 4.30 / 4.36.

Spectral records (IR, NMR) showed the presence of water.

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Example 4

The procedure is similar to Example 1, but 1-hexadecylpyrrolidine-N-oxide was treated, which after evaporation of the solvent was a colorless oil. A dry benzene / dry ethanol (1: 1) mixture was used for drying, and after drying and isolation, an anhydrous product was obtained with m.p. 120-121 ° C, element era for analysis (calculated / found%): 0 = 77.10 / 77.15 and 013.26 / 13.18; N = 4.50 / 4.41.

Spectral records (IR, NMR) showed the absence of water.

Example 5

The procedure is similar to that of Example 1, but 1-methylperhydroazepine N-oxide was treated, which after evaporation of the solvent was a colorless oil. Dry toluene was used for drying and after drying and isolation an anhydrous product was obtained with m.p. 168-170 ° C, elemental analysis (calculated / found%): 0 = 65.08 / 64.89; 11 = 11.70 / 11.62; N = 10.83 / 10.63.

Spectral records (IR, NMR) showed the absence of water.

Claims (1)

OBJECT OF THE INVENTION A process for the isolation of anhydrous non-aromatic amine oxides of the general formula ΓΪ - R o where R denotes an aliphatic chain having carbon numbers 1 to 18 and X denotes (CH ₂ ) ₄ , (CH ₂ ) ₅ , (CH ₂ ) _e , (Cl ₁₂ ) ₇ , (CH ₂ CH ₂ ) ₂ O, (CH ₂ CH ₂ ) ₂ N (O) R, wherein R is as defined above, characterized by subjecting it to azeotropic distillation with dry benzene, or a 1: 1 mixture of dry benzene and dry ethanol, or dry toluene at 50 ° C and pressure 1.6 kPa.