- Method for preparing tetrabutylurea by oil-water two-phase reaction system
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The invention discloses a method for preparing tetrabutylurea by using an oil-water two-phase reaction system, which is characterized in that bis (trichloromethyl) carbonate and dibutylamine are used as raw materials, the oil-water two-phase reaction system is designed and provided, a solvent capable of effectively dissolving bis (trichloromethyl) carbonate and dibutylamine is adopted, meanwhile, a water phase is added into the reaction system to perform liquid seal on the reaction system, can absorb hydrogen chloride gas generated by the reaction at the same time, and promotes the forward proceeding of the whole reaction, and the method has the characteristics of high conversion rate, high selectivity and the like. The method for preparing tetrabutylurea by using the oil-water two-phase reaction system comprises the following steps: dissolving bis (trichloromethyl) carbonate in an organic solvent, placing the solution in a reactor, and simultaneously adding water into the reactor to perform liquid seal on the reaction system; and dissolving dibutylamine in an organic solvent, slowly injecting the dibutylamine into the organic solution of bis (trichloromethyl) carbonate through a micro-injection pump, carrying out chemical reaction, and carrying out refining treatment to obtain the product tetrabutylurea.
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Paragraph 0015-0024
(2021/08/19)
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- Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
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A highly active Pd/TiO2 catalyst system was prepared and applied in the oxidative carbonylation of amines to ureas with ultra-low Pd content under organic ligand and solvent free conditions. The catalytic turnover frequencies (TOFs, moles of amines converted per mole of Pd per h) were 126000 and 250000 h-1 for the production of diphenylurea and dibenzylurea, respectively. An expanded substrate scope including the electron-rich and electron-deficient anilines, primary aliphatic amines, secondary amines was also established. This work offers a straightforward, step economic, and green methodology for the efficient synthesis of valuable ureas.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Shi, Feng
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supporting information
p. 4040 - 4045
(2019/08/07)
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- Synthesis method of tetrabutylurea
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The invention provides a synthesis method of tetrabutylurea. The synthesis method comprises the following steps: dissolving an organic strong base catalyst and dimethyl carbonate into a solvent; raising temperature to 30 DEG C to 50 DEG C to obtain mixed liquid; dropwise adding dibutylamine into the mixed liquid at 50 DEG C to 80 DEG C; after dropwise adding, heating to reflux and keeping the heat and reacting for 5h to 8h to obtain reaction liquid; rectifying the reaction liquid under normal pressure to obtain condensed liquid containing the solvent and residual liquid; decompressing and rectifying the residual liquid to obtain a tetrabutylurea product and residues. According to the synthesis method of the tetrabutylurea, provided by the invention, a toxic raw material, namely phosgene, is not used and hydrogen chloride gas is not generated, so that equipment is not corroded and requirements on the equipment are relatively low; meanwhile, three wastes are avoided; the mass content of the tetrabutylurea in an obtained tetrabutylurea product is 99 percent or more and the yield is 75 percent or more.
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Paragraph 0030-0048
(2017/08/30)
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- Method for preparation of 1, 1, 3, 3-tetrabutylurea by aqueous phase process
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The invention discloses a method for preparation of 1, 1, 3, 3-tetrabutylurea by aqueous phase process. The method includes: adding bis(trichloromethyl)carbonate into a reaction container, and adding water; adding dibutylamine into the aqueous solution of bis(trichloromethyl)carbonate, and controlling the reaction temperature at 0-10DEG C; at the end of charging, further carrying out reaction for 1-9h; at the end of the reaction, separating the organic phase from the aqueous phase, conducting pickling and washing on the organic phase to remove impurities and a small amount of dibutylamine, and drying the organic phase to obtain 1, 1, 3, 3-tetrabutylurea; adding sodium hydroxide into the separated aqueous phase to conduct neutralization, and separating the organic phase to obtain dibutylamine, which can be directly used for reaction. The method takes water as the solvent, the reaction process is carried out at low temperature, and the method has the advantages of safety, environmental protection, low cost and strong operability.
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Paragraph 0013; 0014; 0015; 0016; 0017; 0018; 0019-0022
(2017/03/08)
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- Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides
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The first highly effective Pd/C-catalyzed oxidative N-dealkylation/carbonylation of various aliphatic as well as cyclic tertiary amines with alkynes has been described. The selective sp3 C-N bond activation of tertiary amines at the less steric side using O2 as a sole oxidant and a plausible reaction pathway for the reaction are discussed. The general and operationally simple methodology provides an alternative for the synthesis of a wide range of alk-2-ynamide derivatives under mild conditions. The present protocol is ecofriendly and practical, and it shows significant recyclability.
- Mane, Rajendra S.,Bhanage, Bhalchandra M.
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p. 4974 - 4980
(2016/07/06)
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- Synthesis of urea derivatives from CO2 and amines catalyzed by polyethylene glycol supported potassium hydroxide without dehydrating agents
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Polyethylene glycol supported potassium hydroxide (KOH/PEG1000) was developed as a recyclable catalyst for facile synthesis of urea derivatives from amines and CO2 without utilization of additional dehydrating agents. Primary aliphatic amines, secondary aliphatic amines, and diamines can be converted into the corresponding urea derivatives in moderate yields. Furthermore, the catalyst can be recovered after a simple separation procedure, and reused over 5 times with retention of high activity. Georg Thieme Verlag Stuttgart.
- Kong, De-Lin,He, Liang-Nian,Wang, Jin-Quan
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supporting information; experimental part
p. 1276 - 1280
(2010/06/20)
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- Cobalt/rhodium heterobimetallic nanoparticle-catalyzed oxidative carbonylation of amines in the presence of carbon monoxide and molecular oxygen to ureas
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An environmentally friendly oxidative carbonylation of aliphatic and aromatic primary amines to ureas has been successfully achieved in the presence of a catalytic amount of cobalt/rhodium heterobimetallic nanoparticles without any promoters. The catalyst system could be reused with only a slight loss of catalytic activity.
- Park, Ji Hoon,Yoon, Jae Chun,Chung, Young Keun
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supporting information; experimental part
p. 1233 - 1237
(2009/12/07)
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- A high yielding, one-pot synthesis of substituted ureas from the corresponding amines using Mitsunobu's reagent
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A Mitsunobu-based protocol has been developed for the synthesis of symmetrically and unsymmetrically substituted ureas from a variety of primary and secondary amines using gaseous carbon dioxide, in good to excellent yields. This protocol is mild and efficient compared to other reported methods.
- Chaturvedi, Devdutt,Mishra, Nisha,Mishra, Virendra
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experimental part
p. 267 - 270
(2009/05/26)
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- Hexaalkylguanidinium trifluoromethanesulfonates - A general synthesis from tetraalkylureas and triflic anhydride, and properties as ionic liquids
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More than thirty hexaalkylguanidinium trifluoromethanesulfonates 12 were prepared from N,N-diethyl-N′,N′-dimethylurea, N,N-dibutyl-N′, N′-diethylurea, or tetrabutylurea, triflic anhydride, and a dialkylamine or cyclic sec-amine in two steps. The combination of the urea and triflic anhydride first yields a bis(tetraalkylamidinio)ether bis(triflate) 10, which is then converted into a salt 12 by reaction with the amine component. The reaction sequence can also be carried out as a one-pot procedure. Eighteen of the prepared guanidinium triflates 12 constitute room-temperature ionic liquids, which were characterized for their melting point, glass transition temperature, viscosity, and refractive index. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Kunkel, Helene,Maas, Gerhard
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p. 3746 - 3757
(2008/03/18)
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- METHOD FOR THE CONTINUOUS PRODUCTION OF TETRA-SUBSTITUTED UREAS
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The invention relates to a method for producing tetra-substituted ureas by reacting the corresponding amines with phosgene in the presence of an aqueous inorganic base at a temperature ranging of from 0 to 150 °C. According to the inventive method, the corresponding amine, the phosgene and the aqueous inorganic base are on average continuously fed to the reactor, a two-phase system is formed in the reactor by selecting the tetra-substituted ureas to be produced, by selecting the quantitative ratio of the substances and substance mixtures to be added, by selecting the temperature during reaction and optionally by adding an organic solvent that is not completely miscible with water, and the reaction mixture is discharged from the reactor in an on average continuous manner.
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Page/Page column 14-18
(2008/06/13)
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- Low-temperature synthesis of tetraalkylureas from secondary amines and carbon dioxide
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The reaction of dialkylamines with CO2 giving tetraalkylureas can be performed at 60°C. The reaction requires CCl4, is weakly promoted by DMAN or PPh3, and is not promoted by a Pd catalyst. A two-step procedure, in which dialkylammonium dialkylcarbamate is produced in situ and then reacted with CCl4 and free dialkylamine, gave greater yields of urea than a simple single-stage procedure.
- Tai, Chih-Cheng,Huck, Melissa J.,McKoon, Erin P.,Woo, Tiffany,Jessop, Philip G.
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p. 9070 - 9072
(2007/10/03)
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- A novel ZrO2-SO42- supported palladium catalyst for syntheses of disubstituted ureas from amines by oxidative carbonylation
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The syntheses of disubstituted ureas by carbonylation of a series of amines in the presence of a sulfate modified zirconia supported palladium catalyst was investigated at an initial total pressure of 4.0 MPa and 135°C. High conversions and yields were achieved for the synthesis of symmetric dialkylureas. This supported catalyst could also be easily separated and recovered after reaction.
- Shi, Feng,Deng, Youquan,SiMa, Tianlong,Yang, Hongzhou
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p. 2161 - 2163
(2007/10/03)
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- A Willgerodt-Kindler Type Selenation of Dihalomethane Derivatives, Chloroform, and Sodium Trichloroacetate by Treating with a Base, Elemental Selenium, and an Amine
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Treatment of dihalomethane derivatives, chloroform, or sodium trichloroacetate with elemental selenium in the presence of NaH and an excess amount of an amine gave the corresponding selenoamides, selenoureas, and bis(selenocarbamoyl) triselenides in modest yields. These products were afforded from reactive intermediates related to "selenocarbonyl halides" and "selenophosgenoids" generated by the reaction of dichloromethanide ions and trichloromethanide ion with N-alkylated aminopolyselenide species (R2N-(Se)n-).
- Shimada, Kazuaki,Yamaguchi, Minoru,Sasaki, Tohru,Ohnishi, Kenji,Takikawa, Yuji
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p. 2235 - 2242
(2007/10/03)
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- Convenient Syntheses of N,N-Dialkylselenoamides and N,N,N',N'-Tetraalkylselenoureas by Treating Terminal gem-Dihaloalkanes, Chloroform , or Sodium Trichloroacetate with a Base, Elemental Selenium, and Amines
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Treatment of terminal gem-dihaloalkanes, chloroform or sodium trichloroacetate with elemental selenium in the presence of NaH and an excess amount of primary or secondary amines gave selenoamides and selenoureas in modest yields.
- Takikawa, Yuji,Yamaguchi, Minoru,Sasaki, Tohru,Ohnishi, Kenji,Shimada, Kazuaki
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p. 2105 - 2108
(2007/10/02)
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- Oxidative coupling of amines and carbon monoxide catalyzed by palladium complexes. Mono- and double carbonylation reactions promoted by iodine compounds.
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Iodine is an effective promoter for the carbonylation of primary and secondary amines to ureas using palladium acetate as the catalyst and a base (e.g.K2CO3) in acetonitrile (3 h at 95 deg C and 2.7 atm).Oxamides are formed in excellent yields when secondary amines are carbonylated in the presence of iodide ion and oxygen, while primary amines give ureas as the principal product at 95 deg C, and oxamide at room temperature.
- Pri-Bar, Ilan,Alper, Howard
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p. 1544 - 1547
(2007/10/02)
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- One-Pot Synthesis of N,N,N',N'-Tetrasubstituted Ureas and Oxomalonamides by Oxidative Carbonylation of Lithium Amides at Atmospheric Pressure
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N,N,N',N'-tetrasubstituted ureas have been obtained in good yields by reaction of lithium aliphatic amides in tetrahydrofuran solution with carbon monoxide under mild conditions (0 deg C, 1013 mbar) followed by treatment with oxygen prior to work up.N,N,N',N'-tetrasubstituted oxomalonamides (oxopropanediamides) can be obtained under similar reaction conditions by carrying out the reaction in the presence of known amounts of the pure amine.Besides being an useful synthetic method, the present studies afford new evidence of the mechanism of the reaction.
- Nudelman, Norma S.,Lewkowicz, Elizabeth S.,Perez, Daniel G.
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p. 917 - 920
(2007/10/02)
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