制备了高活性的Pd / TiO 2催化剂体系,并在有机配体和无溶剂条件下,将胺氧化羰基化为具有超低Pd含量的脲。用于生产二苯基脲和二苄基脲的催化转换频率(TOF,每摩尔Pd / h转化的胺的摩尔数)分别为126 000和250 000 h -1。还建立了扩大的底物范围,包括富电子和电子不足的苯胺,脂肪族伯胺,仲胺。这项工作为有效合成有价值的尿素提供了一种简单,经济,绿色的方法。
Environmentally Friendly Synthesis of Urea-Free Poly(carbonate-urethane) Elastomers
作者:Dominik Wołosz、Paweł G. Parzuchowski、Karolina Rolińska
DOI:10.1021/acs.macromol.2c00706
日期:2022.6.28
eco-friendly synthetic pathway toward non-isocyanate poly(carbonate-urethane)s (NIPCUs) obtained from carbon dioxide and its simple derivatives─organic carbonates. Bis(hydroxyalkyl carbamate)s synthesized from ethylene carbonate and appropriate α,ω-diamines were used as polyurethanehardsegment precursors while oligocarbonate diols as softsegment ones. The structures and properties of the obtained
The Conversion of Formamides into Formamidines<sup>1</sup>
作者:H. George Mandel、Arthur J. Hill
DOI:10.1021/ja01644a034
日期:1954.8
USE OF SUBSTITUTED UREAS OR URETHANES FOR FURTHER IMPROVEMENT OF THE COLD FLOW PROPERTIES OF MINERAL OILS AND CRUDE OILS
申请人:BASF SE
公开号:US20130232858A1
公开(公告)日:2013-09-12
The use of substituted monoureas, diureas, polyureas, monourethanes, bisurethanes or polyurethanes of the formula R
1
X—CO—NR
3
R
4
in which X is R
2
N or O and R
1
to R
4
are each independently hydrogen, alkyl radicals, alkenyl radicals, cycloalkyl radicals, aryl radicals or arylalkyl radicals, where at least one variable must comprise 4 carbon atoms and where the urea or urethane functionality may be replicated via bridging members, for further improvement of the cold flow properties of mineral oils and crude oils which already comprise further organic compounds suitable for dispersion or for promoting dispersion of paraffin crystals which precipitate under cold conditions, and organic compounds which improve the cold flow characteristics of mineral oils and crude oils.
Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO<sub>2</sub> with unprecedented activity
作者:Shujuan Liu、Xingchao Dai、Hongli Wang、Feng Shi
DOI:10.1039/c9gc01577a
日期:——
A highly active Pd/TiO2 catalyst system was prepared and applied in the oxidativecarbonylation 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 126 000 and 250 000 h−1 for the production of diphenylurea and dibenzylurea, respectively. An expanded substrate scope
制备了高活性的Pd / TiO 2催化剂体系,并在有机配体和无溶剂条件下,将胺氧化羰基化为具有超低Pd含量的脲。用于生产二苯基脲和二苄基脲的催化转换频率(TOF,每摩尔Pd / h转化的胺的摩尔数)分别为126 000和250 000 h -1。还建立了扩大的底物范围,包括富电子和电子不足的苯胺,脂肪族伯胺,仲胺。这项工作为有效合成有价值的尿素提供了一种简单,经济,绿色的方法。
Hierarchical Self‐Assembly of Amphiphilic β‐
<i>C</i>
‐Glycosylbarbiturates into Multiresponsive Alginate‐Like Supramolecular Hydrogel Fibers and Vesicle Hydrogel
Barbituric acid-mediated Knoevenagel condensation on unprotected carbohydrates enabled the molecular design of amphiphilic β-C-glycosyl barbiturates as hydrogelators. The single-tailed glycoamphiphiles self-assembled into alginate-like multistimuli-triggered and responsive supramolecular hydrogel fibers. While, the double-tailed glycoamphiphiles led to vesicle hydrogels. Barbituric acid proves to be