• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    1510735 Isolating N-methyl-3 and 4-nitrophthalimides GENERAL ELECTRIC CO 23 April 1975 [8 May 1974] 16788/75 Heading C2C A process for isolating a mixture of N- methyl - 3 - nitrophthalimide and N - methyl- 4-nitrophthalimide from a concentrated sulphuric acid solution thereof comprises extracting the solution with methylene chloride. The solution is suitably obtained by contacting a solution of N-methylphthalimide in 98-100% concentrated sulphuric acid with 98-100% concentrated nitric acid at a temperature of from 60‹ to 80‹ C.
    公开号:SU722484A3
    申请号:SU752127885
    申请日:1975-04-25
    公开日:1980-03-15
    发明作者:Чойс Кук Ньюелл；Чарльз Дэвис Гари
    申请人:Дженерал Электрик Компани (Фирма)；
    IPC主号:
    专利说明:

    one
    This invention relates to kecKofl chemistry, specifically to a method for producing N-methyl nitrophthalimides of the general formula
    N-CHj
    N-Methylnitrophthalimides are used in the synthesis of heat-resistant polymers.
    A known method of producing N-methyl nitrophthalimides by treating nitrophthalic anhydride with an aqueous solution of methylamine while cooling and heating the product obtained to 1. After treatment with an aqueous solution of methylamine, the reaction mass is separated from water and thoroughly dried, which complicates the process.
    The disadvantages of this method are its multi-stage due to the presence of an additional step of separation from water and the formation of a significant amount of wastewater.
    The purpose of the invention is to simplify the method of obtaining N-nitrophthalimides and prevent the environment from being contaminated by sewage.
    The goal is achieved by the proposed method of producing N-methyl nitrophthalimides, in that N-methylphthalimide is nitrated with an equimolar amount of 98-100% nitric acid in 90-95% sulfuric acid at 65-75-s and the target product is extracted from the reaction mixture with methylene chloride followed by heating the sulfuric acid thus obtained at 260–325 ° C by passing nitrogen dioxide and returning the sulfuric acid to the beginning of the process.
    The distinguishing features of the process are the reduced conditions for the nitration of N-methylphthalimide and the regeneration of sulfuric acid.
    The technology of the method is as follows.
    A solution of N-methylphthalimide in 98-103% sulfuric acid is prepared and a solution of 98-100% nitric acid thus obtained is nitrated. The nitration reaction is carried out at 65-75 ° C, after which the nitroproduct is extracted with methylene chloride. The proposed method makes it possible to reuse and recycle unspent reagents, sulfuric acid, and also methylene chloride used in the extraction process. Especially important is the fact that it is possible to nitrate N-methylphthalimide to obtain 3-isomer and 4-isomer in amounts close to theoretically. This is achieved using concentrated sulfuric acid, which is the solvent used for this reaction, using concentrated nitric acid, is with a nitrating agent, and further extraction of the products obtained with methylene chloride. In accordance with the invention, the process is carried out at high speed and at moderate temperatures of about 60-80 ° C. Sulfuric acid and methylene chloride, used in this process, can be reused. In this case, it is sufficient to remove 5-7% of the water present in the solution of sulfuric acid and formed as a result of the nitration reaction. The proposed method is suitable for carrying out a nitration reaction in a continuous way, according to which nitric acid is introduced into the process simultaneously with a solution of methylphthalimide in sulfuric acid, and the effluent stream is treated with methylene chloride to extract the obtained nitrated N-methylphthalimide. Unreacted reagents can be sent directly to the process inlet, or should be subjected to a minor treatment (this primarily refers to the removal of 5-7% water). The nitration reaction is carried out at temperatures of 60-80 ° C, preferably 65-75 seconds. If the reaction is carried out at a temperature higher than, the yield of the Target Product decreases due to an increase in the rate of reactions such as oxidation and hydrolysis. If the reaction is carried out at temperatures lower than 60 ° C, the reaction rate decreases significantly, i.e. such a process is not economically feasible. The use of methylene chloride as an extracting agent to isolate the resulting nitro derivatives is also an important feature of the invention for a number of reasons. Attempts to use other halide derivatives, such as chloroform, carbon tetrachloride and methyl chloride, have been unsuccessful, as these substances are unsuitable because of their tendency to decomposition, insufficient volatility and dissolving ability of the relatively nitrated product necessary to ensure effective and rapid extraction. The amount of methylene chloride used may vary widely. For example, for each 1 liter of a mixture containing a nitrated product and a solution of sulfuric acid, it is possible to spend from 0.5 to 8-10 l of methylene chloride and more, depending on the method of extraction. However, when carrying out the extraction process, it is necessary to ensure maximum contact of methylene chloride with a solution of sulfuric acid. The initial sulfuric acid should be 98-103%. With a lower initial concentration of sulfuric acid, a hydrolysis reaction occurs, as well as an oxidation reaction. The water produced as a result of nitration and oxidation reduces the concentration of sulfuric acid to less than 9293%, which in its turn causes precipitation of nitrated N-methylphthalimide. As a result, another problem arises due to the difficulty of separating the products during extraction. In this case, if the concentration of sulfuric acid after the completion of the nitration reaction exceeds 95%, the nitrated product is so strongly bound to sulfuric acid that it cannot be subjected to efficient extraction with methylene chloride. In this case, it is necessary to add a small amount of water to the reaction mixture in order to bring the concentration of sulfuric acid to about 92-95%. The amount of sulfuric acid can vary in the range of 2-4 parts by weight. on 1 weight. N-methylphthalimide. Lower ratios between acid and imide are advisable to use when sulfuric acid has a very high concentration, i.e. more than 100%. A concentration of nitric acid of 98-100% is also necessary in order not to dilute the concentrated sulfuric acid with water. The amount of nitric acid used in this process should be close enough to the stoichiometric one calculated for the introduction of one nitro group into an automatic L-methylphthalimide nucleus. A significant excess amount of nitric acid causes oxidation of nitryuftshimida. A small excess amount of nitric acid, for example, 1.11, 3 moles of nitric acid per 1 mole of N-methylphthalimide, should be used to compensate for the losses in nitric acid caused by the oxidation reactions. In this reaction, N-methyl fluoride and concentrated solution sulfuric acid is mixed in the reactor, equipped with a mixing device and a device for cooling or heating the reactor. After heating the contents of the reactor to a predetermined temperature with constant stirring, slowly add Concentrated nitric acid, and its introduction is carried out below the surface formed by the reaction mixture. The addition of acid is carried out from 10 minutes to 1 hour or more. After stirring for 30 minutes to 2-3 hours at 65-75 ° C, the resulting reaction mixture is sent to an extractor designed for continuous extraction of the sulfuric acid solution with methylene chloride. Such an extractor is similar to a Dean-Stark apparatus and is an extraction column equipped with a stirrer. Methylene chloride (extractant) is continuously introduced into the bottom of the extraction column. In the upper part of the extraction column of the Rolozhek overflow pipe, through which the Dapee extract is drained, the extract enters a vessel equipped with a preheater capable of maintaining a temperature in the range from room temperature to 100 ° C, designed to evaporate methylene chloride and concentrate nitrated N-methylphthalimides, Methylene chloride vapors are condensed and returned to the bottom of the extraction column under the force of gravity and the process continues until the extra is completely completed. ation. Example 1. 161 g (1 mol) of N-methylphthalimide are added to 353 g of 100% in the indicated reactor. The solution is heated with stirring to 70 ° C and then 76.8 g (1.2 mol) of 98.1% HNO are added over 20-25 minutes, and the acid is introduced under the surface of the solution. Stirring of the reaction mixture thus obtained is continued for an additional 1 hour at 70 ° C, and then the solution is cooled to room temperature. The resulting reaction mixture enters an extractor of the type described, intended for the continuous extraction of an acidic solution. About 1 liter of methylene chloride is fed to the extraction unit to start the extraction process. Methylene chloride is passed through a solution of sulfuric acid containing the desired product at a rate of 3 l / h. The first continuous extraction is carried out for 3.5 hours and then the first extraction solution is drained; then another 1 liter of methylene chloride is introduced into the vessel and a second extraction is performed, already within 5 hours. The second extraction CKOpoctb can be increased by bringing the sulfuric acid concentration to 90%, since it is advantageous to carry out the sulfuric acid extraction stage 90-95 . Both extracted parts, consisting mainly of nitrated L methylphthalimides, are passed through a column filled with silica gel in order to separate the residues of sulfuric or nitric acid in an amount of approximately 3%. The mixture thus obtained is then subjected to evaporation under vacuum using a rotary film evaporator. As a result of these operations, after the first extraction stage, 161.8 g (87.9%) of the extracted material are obtained; after the second extraction step, 22.2 g i.e. in total, 184 g are obtained, which is 89.3% of the theoretical yield of nitrated N-methylphthalimides. Gas chromatographic analysis showed that this product contains 94% 4-nitro-N-methylphthalimide, 5% 3-nitro-N-methylphthalimide and 1% unreacted N-methylphthalimide. When the nitroproduct is extracted from sulfuric acid with methylene chloride, excessive dilution of the acid can be avoided. This makes it possible to economically distill the water formed during the nitration and thereby concentrate the sulfuric acid to a degree that allows it to be used again. In order to prevent the staining of the acid, as well as to eliminate the accumulation of organic material resulting from the oxidation reaction, the bubbling of NOg into sulfuric acid is carried out when water is evaporated at 250-325 ° C. This leads to the oxidation of organic material in COj and H., 0, which are removed by the solution, which makes it possible to obtain a colorless or almost colorless 98.3% sulfuric acid, which is an azeotropic compound. Adding SOj to the azeotropic acid makes it possible, if necessary, to easily bring its concentration to 100% or more. Example 2. 100 g of sulfuric acid (dark red), obtained as a result of the nitration procedure described above, are placed in a 1000 ml flask having three throats. The acid is heated to 2 ° C and at this temperature the water is separated and collected and 20 ml of water are collected.
    Then, about 15 g of nitrogen dioxide are bubbled through the acid, and the temperature rises to a flask at a distillate temperature of 323 ° C. This process takes about 90 minutes. Only after entering all 15 g of nitrogen dioxide, sulfuric acid becomes almost colorless. Sulfuric acid, remaining in the flask, has a density of 1/84, which corresponds to a concentration of 98.8%.
    权利要求:
    Claims (1)
    [1]
    1. Flitsch W. Hydrolysis of substituted N-methylftgimidy. Chem. Veg, 94, 2494-501 (1961) (prototype).
    类似技术:
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    同族专利:
    公开号 | 公开日
    AU7914775A|1976-09-23|
    JPS50151871A|1975-12-06|
    US3933852A|1976-01-20|
    BR7502773A|1976-03-16|
    DE2509949C2|1983-06-23|
    FR2270247A1|1975-12-05|
    JPS5953257B2|1984-12-24|
    DE2509949A1|1975-11-27|
    FR2270247B1|1979-06-08|
    GB1510735A|1978-05-17|
    NL7505437A|1975-11-11|
    DD119786A5|1976-05-12|
    IT1037923B|1979-11-20|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4005102A|1974-07-08|1977-01-25|General Electric Company|Process for making 4-nitro-n-methylphthalimide|
    US4017511A|1976-03-24|1977-04-12|General Electric Company|Preparation of aromatic bisimides|
    US4217281A|1976-10-04|1980-08-12|General Electric Company|Imide carbonyl compounds and method for making|
    US4116980A|1976-10-04|1978-09-26|General Electric Company|Method for making aromatic bisor aromatic bis s|
    WO1985002612A1|1983-12-08|1985-06-20|General Electric Company|Method for making n-substituted nitrophthalimides|
    EP0165300B1|1983-12-08|1988-11-09|General Electric Company|Nitration of phthalic acid and phthalic anhydride using nitric acid|
    US4902809A|1983-12-08|1990-02-20|General Electric Company|Method for making N-substituted nitrophthalimides|
    US4599429A|1983-12-08|1986-07-08|General Electric Company|Destruction of DNPI in an all nitric acid nitration process|
    US4921970A|1984-01-03|1990-05-01|General Electric Company|Nitration reactions with acid anhydride promoters|
    US5068353A|1986-12-31|1991-11-26|General Electric Company|Synthesis of aromatic bis compounds|
    US4757149A|1986-12-31|1988-07-12|General Electric Company|Synthesis of bisethers|
    US6008374A|1994-05-27|1999-12-28|General Electric Company|Process for preparing bisusing alkylamine derived bisimides having low melting temperatures|
    EP1776094A2|2004-08-06|2007-04-25|Grain Processing Corporation|Tablet coating composition|
    US8080671B2|2008-05-23|2011-12-20|Sabic Innovative Plastics Ip B.V.|Production of low color polyetherimides|
    WO2017117449A1|2015-12-29|2017-07-06|Sabic Global Technologies B.V.|Methods for the manufacture of an aromatic bisimide and a polyetherimide|
    CN113396146A|2018-12-21|2021-09-14|高新特殊工程塑料全球技术有限公司|For preparing 4-nitro-N- 1-8Process for alkyl) phthalimides|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    US05/468,012|US3933852A|1974-05-08|1974-05-08|Process for making N-methyl nitrophthalimides|
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