- Method for synthesizing 2, 6-dichlorobenzaldehyde by hydrolysis
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The invention discloses a method for preparing 2, 6-dichlorobenzaldehyde by hydrolysis. The method comprises the following steps: heating 2, 6-dichlorobenzyl chloride to 120-160 DEG C, adding a pi complex formed by 0.05-6wt% of a metal salt and benzaldehyde or a benzaldehyde derivative as a catalyst, slowly dropwise adding water with the molar weight equal to that of the 2, 6-dichlorobenzyl chloride, stopping reaction when the content of the 2, 6-dichlorobenzyl chloride is lower than 0.05 wt% to obtain a 2, 6-dichlorobenzaldehyde crude product, and refining to obtain the 2, 6-dichlorobenzaldehyde. 2, 6-dichlorobenzyl chloride is used as a raw material, the used catalyst is the pi complex formed by the metal salt and benzaldehyde, the solubility of the reaction raw material 2, 6-dichlorobenzyl chloride is increased, a homogeneous reaction system is formed, the usage amount is small, a hydrolysis reaction can be initiated at a low temperature, and the reaction is stable. The method has the advantages of mild reaction conditions, high yield, few side reactions and environmental friendliness.
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Paragraph 0017-0019
(2020/10/14)
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- Synthetic method for 2,6-dichlorobenzyl chloride
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The invention discloses a synthetic method for 2,6-dichlorobenzyl chloride. The method is characterized by comprising the following steps: after 2,6-dichlorotoluene is added into a solvent and dissolved, adding a catalyst, performing stirring, under illumination, introducing a chlorine gas, maintaining a reaction, absorbing the reaction tail gas by water, washing the chlorination reaction liquid by using water, performing washing by using an alkali, performing distillation to remove a solvent, performing cooling crystallation, and performing filtration to obtain the 2,6-dichlorobenzyl chloride. According to the method provided by the invention, the reaction yield can reach 90% or more, and the product purity can reache 99% or more.
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Paragraph 0018-0023
(2019/05/16)
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- Method for preparing 2,6-dichlorobenzylidene chloride by low-temperature photochlorination process
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The invention discloses a method for preparing 2,6-dichlorobenzylidene chloride by a low-temperature photochlorination process. The method uses a self-circulating reactor, light with a specific wavelength is selected to initiate a chlorination reaction at a low temperature, and a programmed freezing adjustment technology is adopted in the reaction process to make a raw material completely reactedand generate few impurities. The method for preparing 2,6-dichlorobenzylidene chloride by the low-temperature photochlorination process comprises the following steps: 2,6-dichlorotoluene used as theraw material is added into the self-circulating photochlorination reactor, a light source and a cooling system are turned on, the early reaction temperature is controlled at 70-80 DEG C, and chlorineis slowly introduced; and the temperature is reduced to 30-50 DEG C when the mass content of 2,6-dichlorobenzyl chloride is 50-80%, the reaction is continuously carried out, and the reaction is terminated when the content of the 2,6-dichlorobenzylidene is 95% or above.
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Paragraph 0024-0033
(2019/06/07)
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- Halogenation through Deoxygenation of Alcohols and Aldehydes
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An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3Pa?O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.
- Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
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supporting information
p. 3061 - 3064
(2018/05/28)
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- Rasta resin-triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions
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Heterogeneous polymer-supported triphenylphosphine oxides based on the rasta resin architecture have been synthesized, and applied as reagent precursors in a wide range of halogenation reactions. The rasta resin-triphenylphosphine oxides were reacted with either oxalyl chloride or oxalyl bromide to form the corresponding halophosphonium salts, and these in turn were reacted with alcohols, aldehydes, aziridines and epoxides to form halogenated products in high yields after simple purification. The polymersupported triphenylphosphine oxides formed as a byproduct during these reactions could be recovered and reused numerous times with no appreciable decrease in reactivity.
- Xia, Xuanshu,Toy, Patrick H.
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supporting information
p. 1397 - 1405
(2014/07/22)
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- Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids
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Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)2OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.
- Wang, Zhentao,Zhu, Lin,Yin, Feng,Su, Zhongquan,Li, Zhaodong,Li, Chaozhong
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experimental part
p. 4258 - 4263
(2012/04/10)
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