3720-97-6Relevant articles and documents
Anion-free bambus[6]uril and its supramolecular properties
Svec, Jan,Dusek, Michal,Fejfarova, Karla,Stacko, Peter,Klan, Petr,Kaifer, Angel E.,Li, Wei,Hudeckova, Edita,Sindelar, Vladimir
, p. 5605 - 5612 (2011)
Methods for the preparation of anion-free bambus[6]uril (BU6) are presented. They are based on the oxidation of iodide anion, which is bound inside the macrocycle, utilizing dark oxidation by hydrogen peroxide or photooxidation in the presence of titanium dioxide. Anion-free BU6 was found to be insoluble in any of the investigated solvents; however, it dissolves in methanol/chloroform (1:1) or acetonitrile/water (1:1) mixtures in the presence of the tetrabutylammonium salt of a suitable anion. The association constants with halide ions, BF4-, NO3-, and CN-, were measured by 1H NMR spectroscopy. The highest association constant (8.9×105 M-1) was found for the 1:1 complex of BU6 with I- in acetonitrile/water mixture. A number of crystal structures of BU6 complexes with various anions were obtained. The influence of the anion size on the macrocycle diameter is discussed together with an unusual arrangement of the macrocycles into separate layers.
Dihydroxy methyl dihydroxy ethene carbamide improved preparation method
-
Paragraph 0051; 0052; 0056; 0060, (2017/08/25)
The invention provides a preparation method of dimethylol dihydroxy ethylene urea. The method comprises the following steps: 1, reacting urea with glyoxal in the presence of sulfonic acid and sulfonic acid alkali metal salt at 30-60DEG C for 3-6h to prepare a dihydroxy ethylene urea intermediate; and 2, reacting the dihydroxy ethylene urea intermediate obtained in step 1 with a formaldehyde and optional organic alcohol amine mixture in the presence of dialkali metal hydrogen phosphate and alkali metal dihydrogen phosphate at 40-60DEG C for 2-4h to obtain a target product. The preparation method has the advantages of stable reaction and high conversion rate, and the product has the advantages of high content of active groups, and strong responsivity.
FORMALDEHYDE FREE BINDER COMPOSITIONS WITH UREA-ALDEHYDE REACTION PRODUCTS
-
Paragraph 0135; 0136, (2016/10/27)
Fiber-containing composites are described that contain woven or non-woven fibers, and a cured binder formed from a binder composition that includes (1) a reducing sugar and (2) a crosslinking agent that includes a reaction product of a urea compound and a polycarbonyl compound. Exemplary reaction products for the crosslinking agent may include the reaction product of urea and an α,β-bicarbonyl compound or an α,γ-bicarbonyl compound. Exemplary fiber-containing composites may include fiberglass insulation.