Preparation method of m-fluorotoluene
A technology of m-fluorotoluene and fluorotoluene, which is applied in the field of preparation of fluorine-containing compounds, can solve the problems of product purity and yield reduction, and many side reactions, and achieve the effects of avoiding separation and transfer, reducing side reactions, and increasing yield
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment 1
[0027] The preparation method of m-fluorotoluene of the present invention comprises the following steps:
[0028] 1. Salt forming step: Add 1 mol of m-toluidine dropwise to 2 mol of anhydrous hydrofluoric acid at a constant speed at 5-7°C. The dropping process is completed within 7 hours. Under the condition of insulation reaction for 1 hour, the mixture 1 was obtained;
[0029] 2. Diazotization step: Add 1 mol of sodium nitrite dropwise to mixture 1 at a constant speed under the condition of -3-0°C. The dropping process is completed within 8 hours. React for 1 hour to obtain mixture 2;
[0030] 3. Thermal decomposition step: thermally decompose the 2 mixture, and the thermal decomposition is divided into the following four stages:
[0031] The first stage is 6 hours in total, control the temperature at 0-20°C: control the temperature at 0-4°C in the first hour, control the temperature at 4-8°C in the second hour; control the temperature at 8-12°C in the third hour, and cont...
Embodiment 2
[0040] Prepare according to the preparation method of embodiment 1 mesofluorotoluene, only change the following parameters of the following steps of embodiment 1:
[0041] Salt-forming step: Add 1 mol of m-toluidine dropwise to 5 mol of anhydrous hydrofluoric acid at a constant speed at 5-7°C, the dropping process is completed within 10 hours, and keep warm at 5-7°C after the addition Reacted for 3 hours to obtain mixture 1;
[0042] Diazotization step: Add 1.5 mol of sodium nitrite dropwise to the mixture 1 at a constant speed under the condition of -3-0°C, the dropping process is completed within 10 hours, and then react under the condition of 0-3°C after the addition is completed 3 hours, to obtain mixture 2;
[0043]Recovery of waste hydrofluoric acid: Mix the waste acid with 3mol of 98 mass% sulfuric acid, distill, and the temperature in the distillation pot is from low to high, ensuring that the top temperature of the tower is 40-45°C in the early stage, and the tempera...
Embodiment 3
[0046] Prepare according to the preparation method of embodiment 1 mesofluorotoluene, only change the following parameters of the following steps of embodiment 1:
[0047] Salt-forming step: Add 1 mol of m-toluidine dropwise to 3.5 mol of anhydrous hydrofluoric acid at a constant speed at 5-7°C. The dropping process is completed within 9 hours. Under the insulation reaction for 2 hours, the mixture 1 was obtained;
[0048] Diazotization step: Add 1.5 mol of sodium nitrite dropwise to the mixture 1 at a constant speed under the condition of -3-0°C, the dropping process is completed within 9 hours, and then react under the condition of 0-3°C after the dropwise addition 2 hours, to obtain mixture 2;
[0049] Recovery of waste hydrofluoric acid: Mix the waste acid with 3mol of 98 mass% sulfuric acid, distill, and the temperature in the distillation pot is from low to high, ensuring that the top temperature of the tower is 40-45°C in the early stage, and the temperature of the top...
PUM
| Property | Measurement | Unit |
|---|---|---|
| melting point | aaaaa | aaaaa |
Abstract
Description
Claims
Application Information
Login to View More