Preparation method of organic intermediate 1, 1, 1-tris (hydroxymethyl) ethane

Abstract

The invention discloses a preparation method of an organic intermediate 1, 1, 1-tris (hydroxymethyl) ethane, which comprises the following steps: under the protection of nitrogen, taking n-propionaldehyde and formaldehyde as raw materials, taking Ca (OH) 2 as alkali and taking water as solvent, heating to 20-70 DEG C, reacting, and controlling the reaction time to be 2-9 hours; after the reaction is finished, cooling to room temperature, and adding formic acid to neutralize Ca (OH) 2; concentrating the obtained solution to obtain a dry white solid, adding absolute ethyl alcohol into the dry white solid, dissolving and filtering to remove calcium formate, and washing a filter cake with absolute ethyl alcohol; and concentrating the obtained solution, adding ethyl acetate for recrystallization, filtering and drying to obtain a target product. The method adopts a one-pot method, has the advantages of low raw material cost, mild reaction conditions, simple operation, high yield and the like, and has economic practicability and industrial production prospects.

Description

Technical Field

[0001] The present invention belongs to the field of organic synthesis, and specifically relates to a method for preparing an organic intermediate 1,1,1-tris(hydroxymethyl)ethane. This research is funded by the National Natural Science Foundation of China (22371269). Background Art

[0002] 1,1,1-Tris(hydroxymethyl)ethane, referred to as TME, CAS number: 77-85-0, molecular formula C5H 12 O3, molecular weight 120.15, structure is as follows:

[0003]

[0004] This product is a polyol with three primary hydroxyl groups, which is an odorless white crystalline solid. This product can react with polyacids to generate polyester resins. These polyester resins with hydroxyl groups can be cross-linked and cured with isocyanates, amino resins, etc., or modified with silicone resins, epoxy resins, etc., and used in products with high requirements for high temperature resistance, oxidation resistance, weather resistance, and light retention. In addition, this product can also be used in polyester synthetic lubricants, plasticizers, plastic stabilizers, and titanium dioxide coatings, and has excellent weather resistance, light resistance, and temperature resistance.

[0005] Currently, most of the 1,1,1-tris(hydroxymethyl)ethane synthesis routes use a two-step synthesis method: first, propionaldehyde and formaldehyde are condensed into 2,2-dihydroxymethylpropionaldehyde, and then the aldehyde is reduced to an alcohol. The reaction route is as follows:

[0006]

[0007] At present, there are three types of first-step condensation reactions: calcium method, sodium method and mixed alkali method. The calcium method condensation uses Ca(OH)2 as an alkaline catalyst to catalyze the reaction (US2468718[P]). This method has the advantages of low raw material cost and wide application of by-product calcium formate. The sodium method condensation uses NaOH as an alkaline catalyst to catalyze the reaction (Pan Jinsong, Jia Weibin, Zhang Xiaoqian, Hu Bo. Research on the synthesis process of trimethylolethane [J]. Applied Chemical Industry, 2009, 38(03): 465-468.). Although this method has a considerable yield, the sodium method is currently used in industry to produce 1,1,1-tri(hydroxymethyl)ethane. However, due to high energy consumption, complex process, multiple equipment, high pollution, difficulty in separating by-products, and narrow sales channels, its market competitiveness is affected. There are many types of mixed alkali condensation, among which Mitsubishi Gas Chemical Company used sodium carbonate and sodium bicarbonate as catalysts. There are also other reports on mixed catalysts, such as Ca(OH)2 / NEt3 (Zhou Kaixi, Xie Jiali, Yuan Maolin. Experimental study on separation and purification of trimethylolethane [J]. Resource Development and Market, 2009, 25(05): 388-389+409.), NH3·H2O / NaOH (Wu Zhigang, Gao Jianfeng. Study on synthesis process of trimethylolethane [J]. Shanxi Chemical Industry, 2009, 29(06): 9-11.), Na2CO3 / γ-Al2CO3 and NaOH / γ-Al2CO 3( Wu Zhigang, Gao Jianfeng. Preparation of solid base and its application in the synthesis of trimethylolethane [J]. Shandong Chemical Industry, 2009, 38(12):12-15.), this method also has a high yield, but many are still in the experimental stage.

[0008] There are two reactions for the second step of reducing aldehydes to alcohols: one is catalytic hydrogenation, which generally requires higher pressure, harsh conditions, and high requirements for equipment; the other is to use the Cannizzaro reaction to reduce dimethylolpropionaldehyde with formaldehyde to produce 1,1,1-tris(hydroxymethyl)ethane, which has relatively mild conditions and better applicability. Summary of the invention

[0009] At present, the sodium method condensation has the problems of high energy consumption, difficulty in recovering the byproduct sodium formate, and complex process treatment; at the same time, the process exploration of the mixed alkali method is not mature enough. Therefore, in view of the above problems existing in the prior art, the present invention adopts the calcium method condensation to provide a method for preparing the organic intermediate 1,1,1-tris(hydroxymethyl)ethane with low raw material cost, mild reaction conditions, safety and high efficiency. The present invention adopts a one-pot reaction, which has economic practicality and industrial application prospects.

[0010] The method for preparing the organic intermediate 1,1,1-tris(hydroxymethyl)ethane of the present invention comprises the following steps:

[0011] Under nitrogen protection, propionaldehyde and formaldehyde are used as raw materials, Ca(OH)2 is used as a base, and water is used as a solvent. After heating to 20-70°C, aldol condensation and Cannizzario disproportionation reactions occur, and the reaction time is controlled at 2-9 hours. After the reaction is completed and cooled to room temperature, formic acid is added to neutralize Ca(OH)2. The resulting solution is concentrated to obtain a dry white solid, to which anhydrous ethanol is added to dissolve and filter to remove calcium formate, and then the filter cake is washed with anhydrous ethanol. After the resulting solution is concentrated, ethyl acetate is added for recrystallization, and the target product is obtained after filtration and drying.

[0012] in:

[0013] The molar ratio of propionaldehyde to formaldehyde is controlled to be 1:3.0-5.0.

[0014] The molar ratio of propionaldehyde to Ca(OH)2 is controlled to be 1:0.5-1.0.

[0015] The concentration of n-propanaldehyde is controlled to be 0.5-2.0M.

[0016] The reaction route is as follows:

[0017]

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The reaction solvent selected in the present invention is water, which is cheaper, greener and safer.

[0020] 2. The present invention adopts a "one-pot" synthesis technology, which can be carried out under relatively mild reaction conditions, greatly simplifies the operation process, and has obvious economic practicality.

[0021] 3. The post-processing of the present invention is simple, avoiding complicated industrial operations, and has the prospect of industrial production. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0023] Embodiment 1:

[0024] The synthesis steps of 1,1,1-tris(hydroxymethyl)ethane in this embodiment are as follows:

[0025]

[0026] Under nitrogen protection, 0.9632g (13mmol) calcium hydroxide, 10mL pure water, 5.7ml (70mmol) formaldehyde aqueous solution, 1.1616g (20mmol) propionaldehyde were added to a 100ml round-bottom flask in sequence. After the addition was completed, the mixture was stirred at 35°C for 5h, and then refluxed and stirred at 75°C for 4h. After the reaction was completed and cooled to room temperature, formic acid was added to neutralize Ca(OH)2, and the resulting solution was concentrated to obtain a dry white solid. Anhydrous ethanol was added to dissolve and filter to remove calcium formate, and the filter cake was washed with anhydrous ethanol. After the resulting solution was concentrated, ethyl acetate was added for recrystallization, and a white solid was obtained after filtration and drying, with a yield of 61%. 1 H NMR (400MHz, DMSO-d6), δ4.24-4.22 (t, J = 8Hz, 3H), 3.23-3.21 (d, J = 4Hz, 6H), 0.69 (s, 3H). 13 CNMR (101MHz, DMSO-d6), δ64.52, 41.34, 16.44.

[0027] Embodiment 2:

[0028] The synthesis steps of 1,1,1-tri(hydroxymethyl)ethane in this embodiment are as follows:

[0029]

[0030] The experimental steps of this example are the same as those of Example 1, except that the disproportionation temperature of 75° C. is changed to 55° C. The yield of this example is 70%.

[0031] Embodiment 3:

[0032] The synthesis steps of 1,1,1-tris(hydroxymethyl)ethane in this embodiment are as follows:

[0033]

[0034] The experimental steps of this example are the same as those of Example 1, except that the disproportionation temperature of 75° C. is changed to 35° C. The yield of this example is 85%.

[0035] From the comparison of the results of Examples 1 to 3, the preferred disproportionation temperature is 35°C.

[0036] Embodiment 4:

[0037] The synthesis steps of 1,1,1-tri(hydroxymethyl)ethane in this embodiment are as follows:

[0038]

[0039] The experimental steps of this example are the same as those of Example 3, except that the reaction time is changed from 9 h to 6 h. The yield of this example is 91%.

[0040] Comparing the results of Examples 3 and 4, the preferred reaction time is 6 h.

[0041] Embodiment 5:

[0042] The synthesis steps of 1,1,1-tri(hydroxymethyl)ethane in this embodiment are as follows:

[0043]

[0044] The experimental steps of this example are the same as those of Example 4, except that the reaction concentration of 2.0 M is changed to 0.5 M. The yield of this example is 91%, and the color of the product is whiter than that of Example 4.

[0045] By comparing the results of Examples 4 and 5, the preferred concentration of n-propanal is 0.5M.

[0046] Embodiment 6:

[0047] The synthesis steps of 1,1,1-tri(hydroxymethyl)ethane in this embodiment are as follows:

[0048]

[0049] The experimental steps of this example are the same as those of Example 5, except that the amount of base used is changed from 0.65 equiv to 0.5 equiv. The yield of this example is 85%.

[0050] Comparing the results of Examples 5 to 6, the preferred amount of base is 0.65 equiv.

[0051] Embodiment 7:

[0052] The synthesis steps of 1,1,1-tri(hydroxymethyl)ethane in this embodiment are as follows:

[0053]

[0054] The experimental steps of this example are the same as those of Example 5, except that the amount of each reaction material is increased by 5 times. The yield of this example is 91%.

[0055] This example verifies that the yield of the method remains unchanged after being scaled up, proves that the method is scalable, and provides a certain reference for industrial production.

[0056] The above description is only a general embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing an organic intermediate 1,1,1-tris(hydroxymethyl)ethane, characterized in that: Under nitrogen protection, propionaldehyde and formaldehyde are used as raw materials, Ca(OH)2 is used as base, and water is used as solvent. After heating, aldol condensation and Cannizzario disproportionation reaction occur to generate 1,1,1-tri(hydroxymethyl)ethane. The reaction route is as follows:

2. The preparation method according to claim 1, characterized in that The steps include: Under nitrogen protection, propionaldehyde and formaldehyde are used as raw materials, Ca(OH)2 is used as a base, and water is used as a solvent. After the temperature is raised to 20-70°C, aldol condensation and Cannizzario disproportionation reactions occur, and the reaction time is controlled at 2-9 hours. After the reaction is completed and cooled to room temperature, formic acid is added to neutralize Ca(OH)2, and the resulting solution is concentrated to obtain a dry white solid. Anhydrous ethanol is added thereto to dissolve and filter out calcium formate, and the filter cake is washed with anhydrous ethanol. The resulting solution is concentrated, ethyl acetate is added for recrystallization, and the target product is obtained after filtering and drying.

3. The preparation method according to claim 2, characterized in that: The molar ratio of propionaldehyde to formaldehyde is controlled to be 1:3.0-5.

0.

4. The preparation method according to claim 2, characterized in that: The molar ratio of propionaldehyde to Ca(OH)2 is controlled to be 1:0.5-1.

0.

5. The preparation method according to claim 2, characterized in that: The concentration of n-propionaldehyde in the reaction system is controlled to be 0.5-2.0M.

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