A method for preparing the organic intermediate 1,1,1-tris(hydroxymethyl)ethane

Abstract

The application discloses a preparation method of an organic intermediate 1,1,1-tris(hydroxymethyl)ethane, wherein under nitrogen protection, n-propyl aldehyde and formaldehyde are used as raw materials, Ca(OH)2 is used as an alkali, water is used as a solvent, the temperature is increased to 20-70 DEG C, and then the reaction is carried out for 2-9 hours; after the reaction is completed and the temperature is cooled to room temperature, formic acid is added to neutralize Ca(OH)2. The obtained solution is concentrated to obtain dry white solid, anhydrous ethanol is added to the dry white solid, calcium formate is removed by dissolving and filtering, and the filter cake is washed with anhydrous ethanol. After the obtained solution is concentrated, ethyl acetate is added for recrystallization, and the target product is obtained after filtration and drying. The application has the advantages of one-pot method, low raw material cost, mild reaction condition, simple operation, high yield and the like, and has economic practicability and industrial production prospect.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, specifically relating to a method for preparing the organic intermediate 1,1,1-tris(hydroxymethyl)ethane. This research was supported by the National Natural Science Foundation of China (22371269). Background Technology

[0002] 1,1,1-Tris(hydroxymethyl)ethane, abbreviated as TME, CAS No.: 77-85-0, molecular formula C5H 12 O3, with a molecular weight of 120.15, has the following structure:

[0003]

[0004] This product is a polyol with three primary hydroxyl groups, and is an odorless, white crystalline solid. It can react with polybasic acids to form polyester resins. These hydroxyl-containing polyester resins can be cross-linked and cured with isocyanates, amino resins, etc., or modified with silicone resins, epoxy resins, etc., for use in products requiring high temperature resistance, oxidation resistance, weather resistance, and gloss retention. Furthermore, this product can also be used in polyester synthetic lubricants, plasticizers, plastic stabilizers, and titanium dioxide coatings, exhibiting excellent weather resistance, light resistance, and temperature resistance.

[0005] Most current synthetic routes for 1,1,1-tris(hydroxymethyl)ethane employ a two-step synthesis: first, propionaldehyde and formaldehyde are condensed to 2,2-dihydroxymethylpropionaldehyde, and then the aldehyde is reduced to an alcohol. The reaction route is shown below:

[0006]

[0007] Currently, there are three types of first-step condensation reactions: calcium method, sodium method, and mixed alkali method. Calcium method condensation uses Ca(OH)2 as an alkaline catalyst (US2468718[P]), which has advantages such as low raw material cost and wide application of the byproduct calcium formate. Sodium method condensation uses NaOH as an alkaline catalyst (Pan Jingsong, Jia Weibin, Zhang Xiaoqian, Hu Bo. Research on the synthesis process of trimethylolethane [J]. Applied Chemical Industry, 2009, 38(03):465-468.). Although the yield of this method is also considerable, the sodium method is currently the main method used in industry to produce 1,1,1-tri(hydroxymethyl)ethane. However, due to high energy consumption, complex process, many equipment, large pollution, difficulty in separating byproducts, and narrow sales channels, its market competitiveness is affected. Mixed alkali condensation has a relatively rich variety, among which Mitsubishi Gas... Chemical Company uses sodium carbonate and sodium bicarbonate as catalysts. Other mixed catalysts have also been reported, 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-Al2CO3. 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.), such methods also have high yields, but many are still in the experimental stage.

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

[0009] Currently, sodium condensation suffers from high energy consumption, difficulty in recovering the byproduct sodium formate, and complex processing; meanwhile, the mixed alkali method is not yet fully mature. Therefore, to address these problems in existing technologies, this invention employs calcium condensation, providing a low-cost, mild, safe, and efficient method for preparing the organic intermediate 1,1,1-tris(hydroxymethyl)ethane. This invention utilizes a one-pot reaction, possessing economic practicality and promising prospects for industrial application.

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

[0011] Under nitrogen protection, using propionaldehyde and formaldehyde as raw materials, Ca(OH)₂ as a base, and water as a solvent, aldol condensation and Cannizzario disproportionation reactions occur after heating to 20-70℃, with the reaction time 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. Anhydrous ethanol is added to dissolve and filter to remove calcium formate. The filter cake is then washed with anhydrous ethanol. The resulting solution is concentrated, recrystallized with ethyl acetate, filtered, and dried to obtain the target product.

[0012] in:

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

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

[0015] The concentration of propionaldehyde should be controlled between 0.5 and 2.0 M.

[0016] The reaction route is shown below:

[0017]

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The reaction solvent used in this invention is water, which is cheaper, greener, and safer.

[0020] 2. This invention adopts a "one-pot" synthesis technology, which can be carried out under relatively mild reaction conditions, greatly simplifying the operation process and having obvious economic and practical advantages.

[0021] 3. The post-processing of this invention is simple, avoiding complex industrial operations, and has the potential for industrial production. Detailed Implementation

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

[0023] Example 1:

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

[0025]

[0026] Under nitrogen protection, 0.9632 g (13 mmol) of calcium hydroxide, 10 mL of pure water, 5.7 mL (70 mmol) of formaldehyde aqueous solution, and 1.1616 g (20 mmol) of propionaldehyde were added sequentially to a 100 mL round-bottom flask. After the addition was complete, the mixture was stirred at 35 °C for 5 h, followed by reflux and stirring at 75 °C for 4 h. After the reaction was completed and cooled to room temperature, formic acid was added to neutralize Ca(OH)₂. The resulting solution was concentrated to obtain a dry white solid. Anhydrous ethanol was added to dissolve and filter to remove calcium formate. The filter cake was then washed with anhydrous ethanol. The resulting solution was concentrated, recrystallized with ethyl acetate, filtered, and dried to obtain a white solid 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] Example 2:

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

[0029]

[0030] The experimental procedures in this embodiment are the same as in Example 1, except that the disproportionation temperature is changed from 75°C to 55°C. The yield in this embodiment is 70%.

[0031] Example 3:

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

[0033]

[0034] The experimental procedures in this embodiment are the same as in Example 1, except that the disproportionation temperature is changed from 75°C to 35°C. The yield in this embodiment is 85%.

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

[0036] Example 4:

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

[0038]

[0039] The experimental procedures in this embodiment are the same as in Example 3, except that the reaction time is changed from 9 hours to 6 hours. The yield in this embodiment is 91%.

[0040] Based on the comparison of the results of Examples 3 and 4, the preferred reaction time is 6 hours.

[0041] Example 5:

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

[0043]

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

[0045] Based on the comparison of the results of Examples 4 and 5, the preferred concentration of n-propionaldehyde is 0.5M.

[0046] Example 6:

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

[0048]

[0049] The experimental procedures in this embodiment are the same as in Example 5, except that the amount of alkali used is changed from 0.65 equiv to 0.5 equiv. The yield in this embodiment is 85%.

[0050] Based on the results of Examples 5 and 6, the preferred amount of alkali is 0.65 equiv.

[0051] Example 7:

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

[0053]

[0054] The experimental procedures in this embodiment are the same as in Example 5, except that the amount of each reactant is increased by 5 times. The yield in this embodiment is 91%.

[0055] This embodiment verifies that the yield remains unchanged after scaling up the method, proving that the method is scalable and providing a certain reference for industrial production.

[0056] The above description is merely a general embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on 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 by: Under the protection of nitrogen, 13 mmol of calcium hydroxide, pure water, 70 mmol of an aqueous solution of formaldehyde, 20 mmol of n-propyl aldehyde, and n-propyl aldehyde with a concentration of 0.5 M are sequentially added to a 100 mL round-bottom flask, and after the addition is completed, the flask is placed in a 35°C water bath for stirring for 6 h; after the reaction is completed and cooled to room temperature, formic acid is added to neutralize Ca(OH)2, the obtained solution is concentrated to obtain a dry white solid, anhydrous ethanol is added to the solid, calcium formate is removed by dissolution and filtration, and the filter cake is washed with anhydrous ethanol; After the obtained solution is concentrated, ethyl acetate is added for recrystallization, and after filtration and drying, the target product is obtained with a yield of 91%.

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