TWI225859B - Method for synthesizing maleimide - Google Patents

Abstract

A method for synthesizing maleimide comprises using a two-step process to produce N-phenyl maleimide from aniline and maleic anhydride as raw materials with a yield of over 90% and a purity of over 98.5%. The invented method is simple and suitable for mass production.

Description

1225859

The present invention relates to a synthetic method of maleimine imide, which uses aniline and maleic anhydride as raw materials and adopts a two-step process to make N-benzylmaleimide. (N — phenyi maleim ide) 'The yield of the obtained product is more than 90%, and the purity is more than 98.5%. The process is smooth and easy, which is conducive to mass production. N-phenyl maleimide (N-phenyl maleimide for short) can be used as ABS heat-resistant modifier to improve the heat resistance of ABS resin. In addition, p | 〇 can also be used as a cross-linking agent for polypropylene (P · P) and gas ethylene (PVC). It can also be used as an adhesive modifier to increase the adhesion of metal and rubber. It is widely used.化 raw materials. According to the published literature, there are five synthetic methods of PMI, but they have many disadvantages, which are described as follows: Method 1 is aniline and maleic anhydride in toluene or xylene in the absence of a catalyst at a temperature of 170. Reaction at ~ 180 ° C for several hours (such as reaction formula 1), the yield is only 5-8%. Method 2 is China Invention Patent No. 29955. The catalyst used in the PMI process is an amine and an acid (inorganic or organic) (such as the reaction formula 2). It is also mentioned that the amine salt 'is attached to the carrier and used. Many disadvantages, due to the use of aromatic hydrocarbon solvents in the reaction, the solubility of the amine salt is poor, and the dispersion is difficult. 'Take this amine dispersion (looks like a slurry). Very difficult in the department. Method 3 is U.S. Patent No. 51,360,52, and mentions that aniline and maleic anhydride and organic acids such as p-toluene sulfonic acid (PTSA) are dehydrated in an organic solvent under reflux (using azeotrope), then

1225859 V. Description of the invention (2) Filtration to remove the catalyst PTSA and impurities, and then proceed to the next step. Filtration is quite troublesome and not ideal. (Refer to Reaction Formula 3) Method 4 In the presence of a catalyst, N-ph eny 1 ma 1 earn ic acid and (C0) 2C12 (oxay 1 chloride) and DMF are present. PMI was also obtained by de-HCI reaction. (Refer to the reaction formula 4), but the yield is not good, and there are a lot of HCL problems. Method 5 firstly esterify N-phenylmaleimide and then dealcoholize it with H3P04. And methods 4, 5 parts of the raw materials are expensive, and toxic without commercial value. Reaction formulas (1) to (5) are as follows:

, CH3C00H

ECN CH2C13 / C〇, (5) L > H3PQ4 -lot; CH2C32 > N— < §) ◎

DMF C12 (C0) 2

, C0, C0 -CO-NH, C-OH I o HCI

CH30H Sulfuric acid ^ CO-NH ^ 00 CH 3 ◎ In order to solve the disadvantages of the aforementioned various methods, the present invention was successfully developed. First, maleic anhydride and aniline are reacted to form maleic acid, and then

9105099.ptd Page 5 1225859 V. Description of the invention (3) Water closed loop is completed.

step

In the reaction, an inert organic solvent must be used, such as xylene, toluene, monogas, digas ethane, o-digas benzene, etc. can be used as the reaction solvent, because the malein amino acid is only soluble in polar solvents, Therefore, a little polar solvent such as acetonitrile, tetrahydrofura n, dimethylformamide (DMF, N, N-dimethyl formamide), and N-methylpyrrolidone (N- me thy 1 pyrrol i done (NMP), triethylamine (TEA, tritnylamine) or other tertiary amines. The first stage reaction temperature is 25 ° C ~ 100t at room temperature, preferably 50 ~ 60 ° C. The second stage reaction temperature is 70. (: ~ 200 ° C, preferably 100 ~ 150 ° C. The present invention is characterized in that in addition to maleic anhydride, aniline, and grain media, in addition to DMF, BHT, CH3HS03 As a catalyst, CH3 HSO3 is used as a catalyst for closed-loop dehydration. DMF assists the dissolution to make the reaction faster. In addition to BHT, it can prevent oxidation and prevent the polymer from being produced in the reaction. The method of the present invention is to put cisbutene in the reactor Diacid anhydride, two

1225859 ------- V. Description of the invention (4) 'One by one — sound book BHT CHsHSO3, DMF' Then add aniline to the top and control the temperature at 50 ~ 60 ° C, add it in about 2 hours, Stir for 0.5 hours, then raise the temperature to reflux and dehydrate. About 4 to 5 hours, the dehydration reaches almost the theoretical amount, which is the end point of the reaction. one. The layers are washed in layers, washed with water, then the solvent is distilled off, and then organic solvents such as cyclohexane or digas ethane are added to stir and recrystallize. After filtration and drying, the packaged product is the finished product. The yield of this method is 92%. Above, the purity can reach more than 98.5%. Organic solvents such as cyclohexane or dioxane can be recycled. The catalyst, CH3HS〇3H, and DMF can be reused as long as they are replenished for each reaction, so the synthesis cost is low, the yield is good, and the purity is also good. Example 1 1. In a 1-liter four-neck bottle, put 500 ml of xylene, 103 g (0.5 mole) of maleic anhydride, 5 g of methylsulfonic acid, 20 g of DMF, and 0.5 g of BHT 0.5 ° C to make them completely soluble. Add 93g (10mole) of aniline dropwise from above, and add about 0.5 ~ 1.0 hour dropwise at 60 ~ 70 ° C. The temperature is increased to 1 40 ° C and the solution is dehydrated under reflux. The solution is clarified and matured in about 4 hours. 2. After cooling to 50 C, the insoluble matter is added, and then water iQmi is added, and the water is allowed to stand for 10 minutes, and the water is separated (the water layer is reserved for next use). 3. Add water 2501 to the oil layer to neutralize it at 01110%, temperature 50 ~ 60 ° C, stir for 30 minutes, and allow the layers to stand. At this temperature, add water 2 50 m 1 to the oil layer. 'Washed and layered. 4. Distillation of xylene under reduced pressure and recrystallization with cyclohexane to obtain Malayan

9105099.ptd Article 1225859 V. Description of the invention (5) Amine product, yield 92%, purity 98.5%. Example 2 In a 1-liter four-necked flask, 500 ml of xylene and the recovery liquid of the aqueous layer of Example 1 (2) were heated at 140 ° C under reflux for dehydration, and then cooled to 70. (: Put 103g (1.05mole) of maleic anhydride, 2.0g of p-methanesulfonic acid, 8g of DMF, 0.5g of BHT, and dissolve by heating. The other steps are the same as in Example 1 to obtain the maleimide product. The yield was 91.5% and the purity was 98.6%. Example 3 In a 1L 4-neck flask, 500ml of dibenzobenzene, 1.03g of maleic anhydride (1.05mole), and 5.0g of p-toluenesulfonic acid (PTSA) were added. , DMF2 0g, ΒΤΤ0.5g, other operation steps are the same as in Example 1, the maleimide product was obtained with a yield of 91.0% and a purity of 98.7%. Example 4: Put xylene 50 in a 1 liter four-neck bottle 0 ml and the aqueous layer recovery liquid of Example 3 were dehydrated under reflux, cooled to 7, and charged with 2.0 g of p-toluenesulfonic acid (PT SA), 8 h of DMF, 0.5 g of BHT, and 103 g of maleic anhydride (1,05 m). 〇le), the other steps are the same as in Example 1 'to obtain the maleimide product with a yield of 98.8% and a purity of 98.4%. Example 5 1. In a 1-liter four-necked bottle, 500ml of xylene and cisbutane were added. Ene

9105099.ptd Page 8 1225859 V. Description of the invention (6) 103 g of acid anhydride (1.05 mole), 40 g of DMF, 5.0 g of toluene sulfonic acid, 5.0 g of ΒΗΤ 0.5 g are heated to 50 ° C to make them all Dissolve, add Aniline 93g (K〇m〇ie), 60 ～ 7 (TC, dropwise add about 0.5 ~ 1.0 hour from the top, add and dehydrate for about 2 hours, clarify and ripen 1 Hour 0 2 · Cool to 50 ° C and filter insoluble matters, then add 100ml of water and stir for 10 minutes, let stand and separate the water layer (the water layer is reserved for the next use) 3. Add 250ml of water to the oil layer, use 20 Neutralized with NaOH, temperature 50 ~ 60 ° C, stirred for 10 minutes, and allowed to stand for separation. At this temperature, the oil layer was washed with 250 mlg of water and separated. 4. The xylene was distilled off under reduced pressure and recrystallized with cyclohexane. The Malayanin product was obtained with a yield of 90% and a purity of 98.5%.

9105099.ptd

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Claims (1)

ί225859 mw Zheng II 丨》 I ΊqingΓ ^-, a method for synthesizing maleimidine imine, including the following steps: (1) using aniline and maleic anhydride as raw materials, in the presence of a catalyst and a polar solvent , At 25 ° C ~ 100 ° C; where the catalyst can be DMF (dimethylformamide), BHT (2, 6-di-tert-butyl-4-methylphenol) or CH3HS03; (2) again After dehydration and closed-loop reaction at 70 ~ 150ac heating and reflux; (3) adding a water layer, layering, washing with water, distilling off the solvent, and crystallizing with an organic solvent. 2. The method according to item 1 of the scope of patent application, wherein the reaction temperature of step 1 is preferably 50 ° C ~ 60 ° C. 3. The method according to item 1 of the scope of patent application, wherein the reaction temperature of step 2 is 100 ° C ~ 150 ° c is the best. 4. The method according to item 1 of the scope of patent application, wherein the organic solvent in step 3 is cyclohexane.