- Continuous production process of 2, 3, 5-trichloropyridine
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According to a continuous production process of 2, 3, 5-trichloropyridine, a continuous tubular chlorinator is adopted, pyridine is taken as a starting raw material, chlorination reaction is continuously carried out step by step by virtue of a catalyst 1 and a catalyst 2 which are independently researched and developed, and 2, 5-dichloropyridine and 2, 3, 5-trichloropyridine are prepared in sequence. In the preparation process of a catalyst 1 and a catalyst 2, the mass ratio of 1-chloropropane to imidazole to 2-chloroethyl diphenylphosphine to nickel tetracarbonyl is 1.2: 1: 3.7: 2.5, and the mass ratio of 1-chloropropane to imidazole to 2-chloroethyl diphenylphosphine to sodium hexachlororhodate hydrate is 1.2: 1: 3.7: 15. By means of the continuous tubular chlorinator, cheap and easily available pyridine is used as a starting raw material, chlorine atoms are introduced step by step through catalytic chlorination, the atom economy is good, the reaction selectivity is good, the yield of 2, 3, 5-trichloropyridine can be stabilized at 80% or above, the production efficiency is high, the process is easy to control, and the method is environmentally friendly and suitable for industrial production.
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Paragraph 0015; 0018
(2021/10/30)
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- Simple preparation method of 2, 5-dichloropyridine
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The invention provides a green, safe, simple and convenient preparation method of 2, 5-dihydroxybenzene. The method comprises the following steps: by taking maleic acid diester as an initial raw material, carrying out condensation with nitromethane, hydrogenation cyclization and chlorination to prepare 2, 5-dibromobenzene. The preparation method is simple, easy to operate, high in reaction selectivity and high in product yield and purity; The method disclosed by the invention is low in wastewater yield, environment-friendly and high in reaction safety; the used raw materials are cheap and easily available, and the cost is low.
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- Method for preparing 3,6-dichloro-pyridine-2-carboxylic acid through hydrogenation reduction of 3,4,5,6-tetrachloropyridine-2-carboxylic acid
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The invention discloses a method for preparing 3,6-dichloro-pyridine-2-carboxylic acid through hydrogenation reduction of 3,4,5,6-tetrachloropyridine-2-carboxylic acid and belongs to the technical field of production of chemical products. Under specific conditions of temperature, pressure, PH value and the like, chlorine on a pyridine ring is removed through catalytic hydrogenation and the 3,6-dichloro-pyridine-2-carboxylic acid is prepared. According to the method, a clean and environment-friendly catalytic hydrogenation process is used, the 3,4,5,6-tetrachloropyridine-2-carboxylic acid is subjected to hydrogenation reduction high-selectively to prepare the 3,6-dichloro-pyridine-2-carboxylic acid, highly toxic dangerous goods such as reducing agent hydrazine and dichloromethane are not used in the production process, the reaction conditions are mild, the device is simple and easy and convenient to operate, the cost is low, production zero release of the 3,6-dichloro-pyridine-2-carboxylic acid is realized, popularization and application of the green chemical technology are accelerated, and the method has remarkable economic advantages and environment-friendly advantages.
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Paragraph 0054; 0055; 0056; 0057
(2016/12/01)
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- Glycinatocopper(II) complex as an efficient heterogeneous catalyst for aromatic Finkelstein reaction of aryl and heteroaryl bromides to chlorides
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Glycinatocopper(II) complex 1, readily synthesized from copper chloride and glycine was characterized by various techniques including FTIR, XRD, TGA and SEM analysis. The as-synthesized copper complex was found to be a simple and efficient catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction of aryl and heteroaryl bromides in high to excellent yields. The developed glycinatocopper(II) catalyst could easily be recovered from the reaction mixture and reused successfully for several runs without any loss in catalytic efficiency. The developed methodology represents the first example of the use of heterogeneous catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction.
- Verma, Sanny,Saran, Sandeep,Jain, Suman L.
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p. 178 - 183
(2014/02/14)
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- Copper-catalyzed conversion of aryl and heteroaryl bromides into the corresponding chlorides
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An efficient method for the synthesis of aryl and heteroaryl chlorides is described. The reactions of aryl and heteroaryl bromides with tetramethylammonium chloride proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding chlorides in satisfactory to excellent yields.
- Feng, Xiujuan,Qu, Yiping,Han, Yanlei,Yu, Xiaoqiang,Bao, Ming,Yamamoto, Yoshinori
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supporting information
p. 9468 - 9470
(2012/10/29)
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- Process for preparing halogenopyridine derivatives
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PCT No. PCT/JP97/03144 Sec. 371 Date May 6, 1998 Sec. 102(e) Date May 6, 1998 PCT Filed Sep. 8, 1997 PCT Pub. No. WO98/11071 PCT Pub. Date Mar. 19, 1998A process for preparing halogenopyridine derivatives represented by the general formula (II) wherein X and Y each independently represent a halogen atom, comprises reacting a halogeno-2-sulfonylpyridine derivative represented by the general formula (I) wherein X is as defined above and R1 represents an alkyl group etc., with a halogenating agent. The halogenopyridine derivatives can be produced with high purity and in a simple and easy and industrially advantageous manner.
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- Process for the preparation of 2-halogeno-pyridine derivatives
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A process for the preparation of a 2-halogeno-pyridine of the formula STR1 in which X represents halogen and Y represents halogen, nitro, formyl, cyano, carboxyl, carbamoyl, alkyl, halogenoalkyl, alkoxyalkyl, dialkoxyalkyl, alkoxycarbonyl, alkylaminocarbonyl or dialkylaminocarbonyl, which comprises in a first stage reacting a pyridine 1-oxide of the formula STR2 with an organic nitrogen base A and an electrophilic compound, optionally in the presence of a diluent, to produce a compound of the formula STR3 in which A represents the radical of an organic nitrogen base, and Z- represents an anion formed from an electrophilic compound, optionally isolating and optionally purifying the compound of the formula (III).
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- Preparation of isomer-free 2,5-dichloro-pyridine
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A process for the preparation of isomer-free 2,5-dichloropyridine comprising alkoxylating 2-chloro-pyridine or 2-bromo-pyridine in the presence of a base at elevated temperatures, chlorinating with gaseous chlorine the alkoxylated product at ambient temperatures in an aqueous suspension in the presence of an auxiliary base, a small amount of a catalyst and optionally a small amount of an emulsifier, treating the isomer reaction mixture with a Vielsmeyer-Haack reagent, subjecting 2,5- and 2,3-dichloropyridine mixture to water vapor distillation and crystallizing the crystalline product from an alcohol-water mixture.
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- A Convenient Synthesis of Halogenated 2-Chloropyridines by Transformation of Halogenated 2-Methoxypyridines under Vilsmeier-Haack Conditions
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Several halogenated 2-chloropyridines 2a-2h were conveniently synthesized by transformation of halogenated 2-methoxypyridines 1a-1h under Vilsmeier-Haack conditions in a yield of 50-71percent.
- Shiao, Min-Jen,Shyu, Li-Ming,Tarng, Kai-Yih,Ma, Ying-Tsun
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p. 2971 - 2977
(2007/10/02)
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- Site-Selectivity in the Reaction of 3-Substituted Pyridine 1-Oxides with Phosphoryl Chloride
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Site-selectivity in the reaction of 3-substituted pyridine 1-oxide with phosphoryl chloride was investigated.When a strongly electron-withdrawing group (e.g.CN, CONRR', COOR, or NO2) was substituted at the 3-position, the reaction of 3-substituted pyridine 1-oxides with phosphoryl chloride yielded 3-substituted 2-chloropyridines as the main products.Keywords- site-selectivity; 3-substituted pyridine 1-oxide; phosphoryl chloride; 3-substituted 2-chloropyridine; chlorination
- Yamanaka, Hiroshi,Araki, Tomio,Sakamoto, Takao
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p. 2244 - 2247
(2007/10/02)
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- Polyhalogenoaromatic Compounds. Part 42. 13C N.m.r. Spectra of Polyhalogeno-pyridines and pyrimidines
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13C N.m.r. spectra are reported for a number of polyhaloheno-pyridines and -pyrimidines.Substituent effects have been calculated and the results used to assign structures.
- Iddon, Brian,Mack, Arthur G.,Suschitzky, Hans,Taylor, Jack A.,Wakefield, Basil J.
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p. 1370 - 1380
(2007/10/02)
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- Method for preparing 2,5-dihalo- and 2,5,6-trihalopyridines
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A method for preparing 2,5-dihalo- and 2,5,6-trihalopyridines corresponding to the formula SPC1 Wherein each X independently represents chloro, fluoro or bromo and R represents hydrogen, chloro, fluoro or bromo which comprises reacting a halohydrazinopyridine of one of the formulas SPC2 With an excess of an aqueous alkali metal hydroxide in the presence of a reaction medium from the group consisting of loweralkanols of 1 to 4 carbon atoms and loweralkylglycols of 2 to 4 carbon atoms.
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