A kind of preparation method of fatty acid chloride

Abstract

The present invention belongs to the technical field of organic synthesis, and specifically relates to a method for preparing fatty acid chloride. In the present invention, phosphorus trichloride is added dropwise to fatty acid in a protective gas atmosphere for reaction to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40°C, and the reaction temperature of the dropping process is ≤90°C; the reaction solution is subjected to heat preservation treatment to obtain a heat preservation reaction solution; the heat preservation reaction solution is allowed to stand for stratification to obtain an upper layer solution; the upper layer solution is distilled to obtain the fatty acid chloride. The present invention uses phosphorus trichloride and fatty acid as raw materials, reacts by dropping phosphorus trichloride, and then undergoes heat preservation treatment, standing for stratification and distillation to obtain fatty acid chloride. The fatty acid chloride product obtained by the present invention has high purity, and the preparation method provided by the present invention has high chlorine atom utilization rate, low corrosion to production equipment, and less environmental damage, and has great commercial value.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing fatty acyl chloride. Background Art

[0002] In recent years, fatty acyl chlorides, including neodecanoyl chloride, isononanoyl chloride or isooctanoyl chloride, as important chemical intermediates, have played an important role in the chemical industry. For example, neodecanoyl chloride is widely used in the synthesis of alkyl ketene dimers, organic peroxides, surfactants, pharmaceutical intermediates, etc.

[0003] At present, the traditional method for preparing fatty acid chlorides (including neodecanoyl chloride, isononanoyl chloride or isooctanoyl chloride) is to add thionyl chloride to the corresponding fatty acid and stir for more than 4 hours, and then distill to remove gases such as sulfur dioxide and hydrogen chloride.

[0004] However, the above preparation method is highly corrosive to equipment and harmful to the environment. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing fatty acyl chloride. The preparation method provided by the present invention has high chlorine atom utilization rate of the chlorination reagent, low corrosivity to production equipment, and less environmental harm; at the same time, high-purity fatty acyl chloride can be prepared, and the method has good application prospects.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing fatty acyl chloride, comprising the following steps:

[0008] In a protective gas atmosphere, phosphorus trichloride is added dropwise to a fatty acid to react to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40° C., and the reaction temperature of the dropping process is ≤90° C.;

[0009] The reaction solution is subjected to a heat preservation treatment to obtain a heat preservation reaction solution;

[0010] The insulated reaction solution is allowed to stand for stratification to obtain an upper layer solution;

[0011] The upper layer solution is distilled to obtain the fatty acid chloride.

[0012] Preferably, the fatty acid comprises neodecanoic acid, isononanoic acid or isooctanoic acid; and the fatty acid chloride comprises neodecanoyl chloride, isononanoyl chloride or isooctanoyl chloride.

[0013] Preferably, the mass ratio of the phosphorus trichloride to the fatty acid is 1:1-3.

[0014] Preferably, the initial temperature of the fatty acid is 40-60°C.

[0015] Preferably, the dropping time is ≤ 2 h.

[0016] Preferably, the temperature of the heat preservation treatment is 40-60° C. and the time is 1-2 hours.

[0017] Preferably, the standing and stratifying time is 12 to 15 hours.

[0018] Preferably, the distillation pressure is 0.15-0.2 MPa and the temperature is 80-150°C.

[0019] Preferably, the purity of the fatty acid chloride is ≥98%.

[0020] Preferably, the purity of the fatty acid chloride is 98-99.9%.

[0021] Preferably, the distillation comprises the following steps: evacuating the upper layer solution, and then step-raising the temperature from the initial temperature to the distillation temperature of the fatty acid chloride; the initial temperature is 40-50°C.

[0022] The present invention provides a method for preparing fatty acid chloride, comprising the following steps: in a protective gas atmosphere, phosphorus trichloride is added dropwise to fatty acid for reaction to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40°C, and the reaction temperature of the dropping process is ≤90°C; the reaction solution is subjected to heat preservation treatment to obtain a heat preservation reaction solution; the heat preservation reaction solution is allowed to stand and stratify to obtain an upper layer solution; the upper layer solution is distilled to obtain the fatty acid chloride. The present invention uses phosphorus trichloride and fatty acid as raw materials, and the reaction is prepared by dropping phosphorus trichloride. At the same time, the temperature parameters during the dropping process are controlled, and then the fatty acid chloride is obtained through heat preservation treatment, standing and stratification and distillation. The preparation method provided by the present invention has high utilization rate of chlorine atoms in the chlorination reagent, and the obtained fatty acid chloride product has high purity and high yield. At the same time, the preparation method provided by the present invention has low corrosion to production equipment and less harm to the environment, and has great commercial value.

[0023] Furthermore, in the present invention, the dripping time is 2 hours, and the heat preservation time is 1 hour. The preparation method provided by the present invention can reduce the reaction time and has higher production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The gas chromatogram of the neodecanoyl chloride product prepared in Example 1;

[0025] Figure 2 This is the gas chromatogram of the isooctanoyl chloride product prepared in Example 6. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing fatty acyl chloride, comprising the following steps:

[0027] In a protective gas atmosphere, phosphorus trichloride is added dropwise to a fatty acid to react to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40° C., and the reaction temperature of the dropping process is ≤90° C.;

[0028] The reaction solution is subjected to a heat preservation treatment to obtain a heat preservation reaction solution;

[0029] The insulated reaction solution is allowed to stand for stratification to obtain an upper layer solution;

[0030] The upper layer solution is distilled to obtain the fatty acid chloride.

[0031] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0032] In the present invention, phosphorus trichloride is added dropwise to a fatty acid in a protective gas atmosphere for reaction to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40°C, and the reaction temperature of the dropping process is ≤90°C. In the present invention, the fatty acid preferably includes neodecanoic acid, isononanoic acid or isooctanoic acid. The mass ratio of the phosphorus trichloride to the fatty acid is preferably 1:1-3, preferably 1:1-2.5, and can be 1:2.5, 1:1 or 1:2.1 in the embodiment. The initial temperature of the fatty acid is 40-60°C. The reaction temperature of the dropping process is preferably ≤80°C, and more preferably ≤70°C. In the present invention, when the fatty acid is neodecanoic acid, the initial temperature of the neodecanoic acid is 55-60°C, most preferably 60°C, and the reaction temperature of the dropping process is preferably ≤70°C. When the fatty acid is isononanoic acid, the initial temperature of the isononanoic acid is 45-60°C, most preferably 45°C, and the reaction temperature of the dropping process is preferably ≤70°C. When the fatty acid is isooctanoic acid, the initial temperature of the isooctanoic acid is 40-45°C, most preferably 40°C, and the reaction temperature of the dropwise addition process is preferably ≤50°C. The dropwise addition time is preferably 1-2 hours. In the embodiment, it can be 2 hours. The protective gas is preferably nitrogen.

[0033] After obtaining the reaction solution, the present invention performs a heat preservation treatment on the reaction solution to obtain a heat preservation reaction solution. In the present invention, the heat preservation treatment is performed in a protective gas atmosphere, and the protective gas is preferably nitrogen. The temperature of the heat preservation treatment is preferably 40 to 60° C., and in the embodiment, it can be 40° C., 45° C. or 60° C., and the time is preferably 1 to 2 hours, and in the embodiment, it can be 1 hour. The heat preservation treatment is preferably performed under stirring conditions.

[0034] After obtaining the heat preservation reaction solution, the present invention allows the heat preservation reaction solution to stand for stratification to obtain an upper layer solution. In the present invention, the standing for stratification time is preferably 12 to 15 hours, and in the embodiment it can be 12 hours.

[0035] After obtaining the upper solution, the present invention distills the upper solution to obtain the fatty acid chloride. In the present invention, the fatty acid chloride preferably includes neodecanoyl chloride, isononanoyl chloride or isooctanoyl chloride. The pressure of the distillation is preferably 0.15-0.2MPa; the temperature is preferably 80-150°C, more preferably 90-140°C, and further preferably 105-120°C. In the present invention, when the fatty acid is neodecanoic acid, the pressure of the distillation is preferably 0.2MPa; the temperature is preferably 120±5°C. When the fatty acid is isononanoic acid, the pressure of the distillation is preferably 0.15-0.2MPa; the temperature is preferably 115±5°C. When the fatty acid is isooctanoic acid, the pressure of the distillation is preferably 0.2MPa; the temperature is preferably 110±5°C. In the present invention, the distillation preferably includes the following steps: evacuating the upper solution, and then under the initial vacuum condition obtained by evacuating, step-wise heating from the initial temperature to the distillation temperature of the fatty acid chloride, and performing heat preservation distillation to obtain the fatty acid chloride fraction. The initial temperature of the upper solution of the distillation is preferably 40-50°C. The vacuuming time is preferably 2-3h. The initial vacuum degree obtained after the vacuuming is preferably 4500-5000Pa. The present invention preferably removes phosphorus chloride in the upper solution by vacuuming, and the vacuuming process is the process of dephosphorizing the upper solution. The present invention preferably controls the vacuuming time and the pressure after vacuuming to achieve effective dephosphorization, and removes phosphorus chloride in the upper solution as much as possible, which is conducive to obtaining a higher purity fatty acid chloride product in the subsequent distillation process.

[0036] In the present invention, the initial temperature of the upper solution during the step-wise temperature increase is preferably 40-50°C. The step-wise temperature increase procedure is preferably: each temperature increase is preferably 10°C, and the insulation time after each temperature increase is preferably 1-3 minutes. The present invention preferably further includes: collecting the low-pressure fraction in the low-temperature distillation stage and recycling the low-pressure fraction.

[0037] In the present invention, the purity of the fatty acid chloride is ≥98%, preferably 98-99.9%.

[0038] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0039] Example 1

[0040] Put 500g of neodecanoic acid into a 1000mL four-necked flask, and add 200g of phosphorus trichloride into a constant pressure dropping funnel. Keep a nitrogen atmosphere throughout the reaction process, first heat the neodecanoic acid to 60±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 70℃±2℃. The addition is completed in 2h, and the mixture is kept warm and stirred at 60±2℃ for 1h. After the reaction is completed, stop stirring and heating, pour into a separatory funnel and let stand for 12h until stratification.

[0041] After standing, take the upper clear liquid and discard the lower liquid. Take out the upper clear liquid and pour it into a four-necked flask and vacuum for 3 hours at room temperature with a pressure of 5000Pa. Then start vacuum heating. The initial temperature of vacuum heating is 40-50℃. Use step-by-step heating, 10℃ each time, keep warm for 3 minutes, and then continue heating. First collect the low-pressure fraction to remove the low-pressure fraction waste. Then switch the fraction. The fraction collected at 120±5℃ and 0.2MPa is neodecanoyl chloride. When no fraction is produced, the neodecanoyl chloride product is obtained.

[0042] The gas chromatogram of the neodecanoyl chloride prepared in this example is as follows: Figure 1 As shown by Figure 1 It can be seen that the purity of the neodecanoyl chloride prepared in this example is 98.5%, and the yield is 95.6%.

[0043] Example 2

[0044] Put 20kg of neodecanoic acid into a 30L kettle, and add 8.0kg of phosphorus trichloride into the overhead tank. Keep nitrogen atmosphere throughout the reaction process, first heat the neodecanoic acid to 60±2℃, then slowly add phosphorus trichloride, the temperature does not exceed 70±2℃ during the addition of phosphorus trichloride, the addition is completed in 2h, and the temperature is kept at 60±2℃ for 1h. After the reaction is completed, stop stirring and heating, and let it stand in the kettle for 12h.

[0045] After standing, the yellowish liquid in the lower layer is discharged from the lower port, and the upper liquid is vacuumed at room temperature for 3 hours at a pressure of 5000Pa, and then the temperature is raised at a negative pressure. The initial temperature of the negative pressure heating is 40-50°C, and the temperature is raised in a step-by-step manner, with each temperature rising by 10°C. After keeping the temperature for 3 minutes, the temperature is raised again, and the low-pressure fraction is first collected for low-pressure fraction waste removal. Then the fraction is switched, and the fraction collected at 120±5°C and 0.2MPa is neodecanoyl chloride, and the neodecanoyl chloride product is obtained until no fraction is produced.

[0046] The purity of the neodecanoyl chloride prepared in this example is 99.8%, and the yield is 96.2%.

[0047] Example 3

[0048] Put 224g of isononanoic acid into a 500mL four-necked flask, and add 217g of phosphorus trichloride into a constant pressure dropping funnel. Keep a nitrogen atmosphere throughout the reaction process, first heat the isononanoic acid to 45±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 70±2℃. The addition is completed in 2h, and the temperature is kept at 45±2℃ for 1h. After the reaction is completed, stop stirring and heating, pour into a separatory funnel and let stand for 12h.

[0049] After standing, take the upper clear liquid and discard the lower liquid. Take out the upper clear liquid and pour it into a four-necked flask and evacuate it at room temperature under negative pressure for 3 hours at a pressure of 5000Pa, then start negative pressure heating. The initial temperature of negative pressure heating is 40-50°C, and the temperature is raised in a step-by-step manner, with each temperature rising by 10°C. After keeping the temperature for 3 minutes, continue to heat it up, first collect the low-pressure fraction to remove the low-pressure fraction waste. Then switch the fraction, and the fraction collected at 115±5°C and 0.15MPa is isononanoyl chloride, until no fraction is produced, and the isononanoyl chloride product is obtained.

[0050] The purity of the isononanoyl chloride prepared in this example is 99.9%, and the yield is 96.3%.

[0051] Example 4

[0052] Put 20.3kg of isononanoic acid into a 50L kettle, and add 19.7kg of phosphorus trichloride into the overhead tank. Keep nitrogen atmosphere throughout the reaction process, first heat the isononanoic acid to 45±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 70±2℃. The addition is completed in 2 hours, and the temperature is kept at 45±2℃ for 1 hour. After the reaction is completed, stop stirring and heating and let it stand in the kettle for 12 hours.

[0053] After standing, the yellowish liquid in the lower layer is discharged from the lower port, and the upper liquid is evacuated at room temperature and negative pressure for 3 hours, and then the temperature is raised under negative pressure, with a pressure of 5000Pa. The initial temperature of the negative pressure heating is 40-50°C, and the temperature is raised in a step-by-step manner, with each temperature rising by 10°C. After keeping the temperature for 3 minutes, the temperature is continued to rise, and the low-pressure fraction is first collected for low-pressure fraction waste removal. Then the fraction is switched, and the fraction collected at 115±5°C and 0.15MPa is isononanoyl chloride, and the isononanoyl chloride product is obtained until no fraction is produced.

[0054] The purity of the isononanoyl chloride prepared in this example is 99.8%, and the yield is 96.5%.

[0055] Example 5

[0056] Put 250g of isooctanoic acid into a 500mL four-necked flask, and add 119g of phosphorus trichloride into a constant pressure dropping funnel. Keep a nitrogen atmosphere throughout the reaction process, first heat isooctanoic acid to 40±2°C, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 50±2°C, and the addition is completed in 2h, and the temperature is kept at 40±2°C for 1h. After the reaction is completed, stop stirring and heating, pour into a separatory funnel and let stand for 12h until stratification.

[0057] After standing, take the upper clear liquid and discard the lower liquid. Take out the upper clear liquid and pour it into a four-necked flask and vacuum for 3 hours at room temperature with a pressure of 5000Pa. Then start vacuum heating. The initial temperature of vacuum heating is 40-50℃. Use step-by-step heating, 10℃ each time. First collect the low-pressure fraction to remove the low-pressure fraction waste. Then switch the fraction. The fraction collected at 110±5℃ and 0.2MPa is isooctanoyl chloride. When no fraction is produced, the isooctanoyl chloride product is obtained.

[0058] The purity of the isooctanoyl chloride prepared in this example is 99.5%, and the yield is 96.3%.

[0059] Example 6

[0060] Put 20kg of isooctanoic acid into a 50L kettle, and add 9.5kg of phosphorus trichloride into the overhead tank. Keep nitrogen atmosphere throughout the reaction process, first heat isooctanoic acid to 40±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 50±2℃. The addition is completed in 2h, and the temperature is kept at 40±2℃ for 1h. After the reaction is completed, stop stirring and heating, and let it stand in the kettle for 12h.

[0061] After standing, the yellowish liquid in the lower layer is discharged from the lower port, and the upper liquid is vacuumed at room temperature for 3 hours at a pressure of 5000Pa, and then the temperature is raised at a negative pressure. The initial temperature of the negative pressure heating is 40-50°C, and the temperature is raised in a step-by-step manner, with each temperature rising by 10°C. After keeping the temperature for 3 minutes, the temperature is raised again, and the low-pressure fraction is first collected for low-pressure fraction waste removal. Then the fraction is switched, and the fraction collected at 110±5°C and 0.2MPa is neodecanoyl chloride, and the isooctanoyl chloride product is obtained until no fraction is produced.

[0062] The gas chromatogram of the isooctanoyl chloride product prepared in this embodiment is as follows Figure 2 As shown, the purity of the isooctanoyl chloride prepared in this example is 97.6% and the yield is 95.3%.

[0063] Comparative Example 1

[0064] Put 20kg of isooctanoic acid into a 50L kettle and add 6kg of phosphorus trichloride into the overhead tank. Keep nitrogen atmosphere throughout the reaction process. First, heat isooctanoic acid to 40±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 50±2℃. The addition is completed in 2h, and the temperature is kept at 40±2℃ for 1h. After the reaction is completed, stop stirring and heating, and let it stand in the kettle for 12h.

[0065] After standing, the yellowish liquid in the lower layer is discharged from the lower port, and the upper liquid is vacuumed at room temperature for 3 hours at a pressure of 5000Pa, and then the temperature is raised at a negative pressure. The initial temperature of the negative pressure heating is 40-50°C, and the temperature is raised in a step-by-step manner, with each temperature rising by 10°C. After keeping the temperature for 3 minutes, the temperature is raised again, and the low-pressure fraction is first collected for low-pressure fraction waste removal. Then the fraction is switched, and the fraction collected at 110±5°C and 0.2MPa is neodecanoyl chloride, and the isooctanoyl chloride product is obtained until no fraction is produced.

[0066] The purity of the isooctanoyl chloride prepared in this comparative example is 75.5%, and the yield is 85.3%.

[0067] Comparative Example 2

[0068] Put 500g of neodecanoic acid into a 1000mL four-necked flask, and add 200g of phosphorus trichloride into a constant pressure dropping funnel. Keep a nitrogen atmosphere throughout the reaction process, first heat the neodecanoic acid to 60±2℃, and then slowly add phosphorus trichloride. During the addition of phosphorus trichloride, the temperature does not exceed 70℃±2℃. The addition is completed in 2h, and the mixture is kept warm and stirred at 60±2℃ for 1h. After the reaction is completed, stop stirring and heating, pour into a separatory funnel and let stand for 12h until stratification.

[0069] After standing, take the upper clear liquid and discard the lower liquid. Take out the upper clear liquid and pour it into a four-necked flask and vacuum for 3 hours at room temperature with a pressure of 5000Pa. Then start vacuum heating. The initial temperature of vacuum heating is 40-50℃. Use step-by-step heating, 10℃ each time, keep warm for 3 minutes, and then continue heating. First collect the low-pressure fraction to remove the low-pressure fraction waste. Then switch the fraction. The fraction collected at 100±5℃ and 0.2MPa is neodecanoyl chloride. When no fraction is produced, the neodecanoyl chloride product is obtained.

[0070] The purity of the neodecanoyl chloride prepared in this comparative example is 92.4%, and the yield is 78.2%.

[0071] Comparative Example 3

[0072] Put 500g of neodecanoic acid into a 1000mL four-necked flask, and add 200g of phosphorus trichloride into a constant pressure dropping funnel. Keep a nitrogen atmosphere throughout the reaction process, first heat the neodecanoic acid to 50±2℃, and then slowly add phosphorus trichloride. When adding phosphorus trichloride, the temperature does not exceed 60℃±2℃. The addition is completed in 2h, and the mixture is kept at 50±2℃ and stirred for 1h. After the reaction is completed, stop stirring and heating, pour into a separatory funnel and let stand for 12h until stratification.

[0073] After standing, take the upper clear liquid and discard the lower liquid. Take out the upper clear liquid and pour it into a four-necked flask and vacuum for 3 hours at room temperature with a pressure of 5000Pa. Then start vacuum heating. The initial temperature of vacuum heating is 40-50℃. Use step-by-step heating, 10℃ each time, keep warm for 3 minutes, and then continue heating. First collect the low-pressure fraction to remove the low-pressure fraction waste. Then switch the fraction. The fraction collected at 120±5℃ and 0.2MPa is neodecanoyl chloride. When no fraction is produced, the neodecanoyl chloride product is obtained.

[0074] The purity of the neodecanoyl chloride prepared in this comparative example is 92.5%, and the yield is 82.2%.

[0075] As can be seen from the above embodiments, the preparation method of the fatty acid chloride provided by the present invention uses phosphorus trichloride and fatty acid as raw materials, reacts by dropping phosphorus trichloride, and then undergoes heat preservation treatment, static stratification and distillation to obtain fatty acid chloride. The fatty acid chloride product prepared by the present invention has high purity, and the preparation method provided by the present invention has low corrosiveness to production equipment and less environmental harm, and can reduce reaction time, higher production efficiency, and has great commercial value.

[0076] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing fatty acid chloride, characterized in that: The following steps are involved: In a protective gas atmosphere, phosphorus trichloride is added dropwise to a fatty acid to react to obtain a reaction solution, wherein the initial temperature of the fatty acid is ≥40° C., and the reaction temperature of the dropping process is ≤90° C.; The reaction solution is subjected to a heat preservation treatment to obtain a heat preservation reaction solution; The insulated reaction solution is allowed to stand for stratification to obtain an upper layer solution; The upper layer solution is distilled to obtain the fatty acid chloride.

2. The preparation method according to claim 1, characterized in that: The fatty acid includes neodecanoic acid, isononanoic acid or isooctanoic acid; the fatty acid chloride includes neodecanoyl chloride, isononanoyl chloride or isooctanoyl chloride.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the phosphorus trichloride to the fatty acid is 1:1-3.

4. The preparation method according to claim 1 or 2, characterized in that: The initial temperature of the fatty acid is 40-60°C.

5. The preparation method according to claim 1, characterized in that: The dropping time is ≤2h.

6. The preparation method according to claim 1, characterized in that: The temperature of the heat preservation treatment is 40-60° C. and the time is 1-2 hours.

7. The preparation method according to claim 1, characterized in that: The standing and stratifying time is 12 to 15 hours.

8. The preparation method according to claim 1, characterized in that: The distillation pressure is 0.15-0.2 MPa; the temperature is 80-150°C.

9. The preparation method according to claim 1, characterized in that: The purity of the fatty acid chloride is ≥98%.

10. The preparation method according to claim 9, characterized in that: The purity of the fatty acid chloride is 98-99.9%.

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