Search

CN-122010746-A - Method for preparing aromatic amide by heterogeneous reductive amidation of nitroaromatic hydrocarbon

CN122010746ACN 122010746 ACN122010746 ACN 122010746ACN-122010746-A

Abstract

The invention particularly relates to a method for preparing aromatic amide by nitroaromatic hydrocarbon heterogeneous one-pot reductive amidation, which comprises the step of carrying out reductive amidation reaction on nitroaromatic hydrocarbon compounds, acetic acid and hydrogen in the presence of a heterogeneous monoatomic palladium catalyst to synthesize a high-added-value aromatic amide product widely applied to paracetamol medicines. The process adopts the Pd-based monoatomic catalyst supported by the novel nitrogen-carbon carrier, and ensures that the synthesis process of the aromatic amide medicine is simpler, the reaction activity is excellent, the stability is high and the service life of the catalyst is long under the condition of no additional acid auxiliary agent or halogen.

Inventors

  • DING YUNJIE
  • CAI YUTONG
  • SONG XIANGEN
  • YAN LI

Assignees

  • 中国科学院大连化学物理研究所

Dates

Publication Date
20260512
Application Date
20241111

Claims (8)

  1. 1. A method for preparing aromatic amide by one-pot reductive amidation of nitroarene is characterized in that nitroarene, acetic acid and hydrogen are subjected to reductive amidation reaction in a reactor in the presence of Pd-based monoatomic catalyst loaded by a nitrogen-containing carbon carrier to synthesize aromatic amide compounds.
  2. 2. The method of claim 1, wherein the step of determining the position of the substrate comprises, The nitroarene mainly comprises one or more than two of nitrobenzene, o-nitrobenzene, m-nitrobenzene, p-nitrochlorobenzene, p-nitrophenol, p-nitrobenzoic acid, p-nitromethanol and methyl p-nitrobenzoate; The solvent adopted in the one-pot reductive amidation reaction mainly comprises one or more than two of tetrahydrofuran, acetone, toluene, dimethylformamide, N-methylpyrrolidone and 1, 3-dimethyl-2-imidazolidinone.
  3. 3. The method according to claim 1, wherein the nitroaromatic compound is reduced and amidated at a reaction temperature of 373-473 k (preferably 393-4573 k, more preferably 413-433 k) and a reaction pressure of 0.2-10.0 mpa (preferably 0.6-6.0 mpa, more preferably 1-5 mpa) in one pot.
  4. 4. The method according to claim 1 or 2 or 3, wherein the molar ratio of nitroarene starting material to acetic acid is 1:0.1 to 1:10 (preferably 1:1 to 1:10, more preferably 1:4 to 1:10) and the molar ratio of nitroarene starting material to hydrogen is 1:1 to 1:50 (preferably 1:10 to 1:50, more preferably 1:20 to 1:50).
  5. 5. The method according to claim 1, 2 or 3, wherein the nitroarene one-pot reductive amidation reaction is performed using a batch kettle reactor; The liquid product is filtered and separated from the catalyst, and is further rectified or flash evaporated to obtain the aromatic amide product with high purity.
  6. 6. The method of claim 1, wherein the nitrogen-carbon supported Pd single-atom catalyst consists of an active metal, carbon support containing nitrogen heteroatoms.
  7. 7. The method according to claim 6, wherein the active metal component Pd is 0.1% -5% (preferably 0.5% -5%, more preferably 1% -2%) of the total weight of the catalyst, and the nitrogen atom molar content is 10% -30% (preferably 15% -30%, more preferably 15% -25%) of the catalyst.
  8. 8. The method according to claim 1, wherein the one-pot reductive amidation reaction is capable of performing an integrated reaction with high stability using only the heterogeneous Pd-based catalyst without adding an additional acid aid or halogen aid.

Description

Method for preparing aromatic amide by heterogeneous reductive amidation of nitroaromatic hydrocarbon Technical Field The invention relates to a process method for preparing aromatic amide by adopting a Pd-based monoatomic catalyst loaded by a nitrogen-carbon carrier for nitroarene heterogeneous one-pot reductive amidation, belonging to the technical field of heterogeneous catalysis. Background Aromatic amides are organic compounds having a benzene ring and an amide (-NHCO-) group, which are widely found in agrochemicals, pharmaceuticals and medical materials. Because of the heating problems caused by various epidemic diseases in recent 5 years, the demand of paracetamol drugs is greatly increased, and the most basic structural unit is aromatic amide, namely the common acetaminophen product. In addition, it has excellent thermal stability, and is used as an additive in the preparation of polymers to improve mechanical strength, durability and chemical life of materials, and thus is also widely used in the field of aerospace and automobile manufacturing. According to the conventional art synthesis, the amide group is produced by the acylation condensation of carboxylic acid (derivative) and amine in the presence of stoichiometric amounts of coupling agent, with the co-production of equimolar amounts of water. A variety of activators are commonly used in conventional amidation syntheses to catalyze this process, such as KI, mn, TMSI and PPh 3, which all result in a catalytic system that produces large amounts of waste streams that require recovery. Thus, the conventional process is faced with both toxicity and cost of the reaction process and purification and separation of additives and adjuvants in the product system. In order to improve the synthesis mode of the traditional amide, the preparation of the aromatic amide by direct reduction amidation from nitroaromatic hydrocarbon becomes an important means for reducing cost and enhancing efficiency. At least one reaction process can be dispensed with in this coupling process step. The method mainly comprises the following two paths of ① metal Pd and a diphosphine ligand for catalyzing nitroarene reduction and alkene hydro-aminocarbonylation to prepare various organic amides, wherein alkene substrates can be replaced by halohydrocarbon in an equivalent way, ② nitrobenzene reduction and carboxylic acid or ester amidation are combined, and expensive Zn/TMSCl or PhSiH 3 additives are used as efficient reducing agents for coupling two steps of reactions. It can be seen that almost no reported invention can directly reduce amidation of nitroaromatics to aromatic amides without addition of auxiliaries. But combines the advantages of heterogeneous catalysts in catalytic reactions, and can be recovered in a reaction system by a simple separation method and realize the cycling stability of the catalysts by constructing various carriers. Further development and preparation of heterogeneous single-atom catalyst can also enable a small amount of noble metal to exert high-efficiency utilization rate and activity. The preparation method of the monoatomic catalyst mainly comprises the following three methods of ①, namely, preparing an oxide with an atomic defect, inserting other active metals in a bonding way to realize the stabilization of the monoatom, ②, designing a molecular sieve with a specific structure, limiting the metals to a specific cage structure through a limiting domain effect to prevent the metals from polymerizing into large nano particles, and ③, constructing a heteroatom carrier with N, S, P or I, anchoring the impregnated metals in an atomic bonding way to ensure that the monoatom exists stably. Thus, the use of heterogeneous single-atom catalysts for direct reductive amidation of nitroarenes to aromatic amides is a good strategy to reduce costs and improve atomic economy. In conclusion, the nitroarene one-pot reductive amidation reaction to obtain the aromatic amide compound with high added value has important research value. The development of green clean heterogeneous monoatomic catalysts for high efficiency separations at low cost, and the implementation of heterogeneous reactions, is also a major research direction in recent years. The two are combined for application, so that the aromatic amide productivity is improved, the cost reduction and the synergy are realized, and the method has great advantages in industrial development and process planning. Disclosure of Invention In view of the shortcomings in the existing researches, the invention aims to provide a heterogeneous Pd monoatomic catalyst which can be easily and industrially separated and has excellent reaction activity, and is used for realizing the nitroarene one-pot reductive amidation reaction. The invention provides a method for nitroarene one-pot reductive amidation reaction, which adopts a multiphase nitrogen-carbon carrier loaded single-atom Pd catalyst, and consists of active metal