Thermal and X‐ray powder diffraction studies of aliphatic polyester dendrimers

The syntheses and thermal and X‐ray powder diffraction analyses of three sets of aliphatic polyester dendrimers based on 2,2‐bis(hydroxymethyl)propionic acid as a repeating unit and 2,2‐dimethyl‐1,3‐propanediol, 1,5‐pentanediol, and 1,1,1‐tris(hydroxymethyl)ethane as core molecules are reported. These dendritic polyesters were prepared in high yields with the divergent method. The thermal properties of these biodendrimers were evaluated with thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition of the compounds occurred around 250 °C for the hydroxyl‐ended dendrimers and around 150 °C for the acetonide‐protected dendrimers. In addition, the crystallinity of the lower generation dendrimers was evaluated with X‐ray powder diffraction. The highest crystallinity and the highest melting points were observed for the first‐generation dendritic compounds. The higher generation dendrimers showed weaker melting transitions during the first heating scan. Only the glass‐transition temperatures were observed in subsequent heating scans. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5574–5586, 2004     

Tris(hydroxymethyl)aminomethane as an efficient organobase catalyst for the synthesis of β-phosphonomalonates

Tris(hydroxymethyl)aminomethane (THAM) is a highly efficient and recyclable organobase catalyst for the nucleophilic phosphonylation of benzylidene malononitrile under solvent-free conditions. This new catalytic methodology is applicable without a solvent, eco-friendly, economically viable, avoids conventional isolation procedures, and has a facile work-up procedure and wide scope. THAM is an inexpensive, commercially available, non-toxic, and biodegradable novel organocatalyst. Furthermore, it can be reused in up to five cycles without loss in catalytic activity, and no chromatographic separation is needed to obtain the desired products.     

Synthesis and characterization of fully biobased poly(propylene succinate‐ran‐propylene adipate). Analysis of the architecture‐dependent physicochemical behavior

Fully biobased aliphatic random poly(1,3‐propylene succinate‐ran‐1,3‐propylene adipate) (PPSA) copolyesters with high molar mass were synthesized with different macromolecular architectures based on various succinic acid/adipic acid (SA/AA) molar ratio, by transesterification in melt. Titanium (IV) isopropoxide was used as an effective catalyst. All synthesized copolyesters were fully characterized by different chemical and physicochemical techniques including NMR, size exclusion chromatography, FTIR, wide angle X‐ray scattering, differential scanning calorimetry, and thermogravimetric analysis. The final copolyesters molar compositions were identical to the feed ones. The different sequences based on succinate and adipate segments were randomly distributed along the chains. All the corresponding copolyesters showed an excellent thermal stability with a degradation onset temperature higher than 290 °C, which increased with the adipate content. According to their compositions and architectures, PPSA copolyesters can exhibit or not a crystalline phase, at room temperature. T_g of copolyesters decreased with the adipate content due to the decrease in the chains mobility, following the Gordon–Taylor relation. PPSA showed a pseudo eutectic melting behavior characteristic of an isodimorphic character. Finally, PPSA copolyesters were not able to crystallize during the cooling or the second heating run, due to the 1,3‐propanediol chemical structure, which led to amorphous materials with the exception of the polyester based solely on AA. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2738–2748     

Effect of tris(hydroxymethyl) aminomethane on the phase behavior of poly(ethylene imine)/cinnamic acid conjugate and the release property of cubic phase containing the conjugate

The upper critical solution temperature (UCST) of poly(ethylene imine)/cinnamic acid (PEI/CA) conjugate decreased as the tris(hydroxymethyl) aminomethane (THMAM) concentration increased. On the optical micrographs of PEI/CA mixture solutions at 25°C, the microspheres were found when the THMAM concentration was 0?mM and 100?mM, but hardly found at 200?mM. Monoolein (MO) cubic phase containing PEI, CA, and THMAM exhibited a bilayer structure on the TEM micrograph. The release degree of methylene blue loaded in the cubic phase was not strongly dependent on THMAM concentration at 25°C and 37°C, but strongly dependent on the concentration at 50°C.     

1,3-丙二醇油酸双酯的合成

以对甲苯磺酸为催化剂,油酸和1,3-丙二醇为原料合成了1,3-丙二醇油酸双酯。最佳反应条件为:油酸60 mmol,n(油酸)∶n(丙二醇)=2.1,催化剂对甲苯磺酸的用量为油酸质量的3.5%,带水剂甲苯20 mL,于160℃反应1 h。在优化反应条件下,酯化率98%,收率77%。     

Reactions of divalent transition metal halides with 3,5-dimethyl-1-(hydroxymethyl)-pyrazole

Factors determining the complex formation reaction of copper(II), nickel(II) and cobalt(II) chloride and copper(II) bromide with 3,5-dimethyl-1-(hydroxymethyl)-pyrazole (HL) has been studied. Depending on experimental conditions, complexes with different composition were obtained: [CuCl₂(dmp)]₂ (I), [CuCl₂(dmp)₂]₂ (II), [CoCl₂(dmp)₂] (III) (dmp=3,5-dimethylpyrazole), [CuBr(L)]₂ (IV), [CoCl(L)(EtOH)]₄ (V) and [NiCl(L)(EtOH)]₄ (VI). The compounds were characterized by FTIR spectroscopy, solution conductivity and magnetic measurements. The crystal structure of [CoCl(L)(EtOH)]₄ has been determined by single crystal X-ray diffraction. The thermal decomposition of the compounds was studied and found to be continuous for all of the compounds. The desolvation mechanism of [MCl(L)(EtOH)]₄ (M=Co(II), Ni(II)) is explained on the basis of the route of complex formation of CoCl₂ with HL.     

Glycolurils in α-ureido-and α-aminoalkylation reactions 1. α-Ureidoalkylation of sulfamides with <Emphasis Type="Italic">N</Emphasis>-(hydroxymethyl)glycolurils

α-Ureidoalkylation of sulfamides with 2-hydroxymethyl-, 2,6-and 2,8-bis(hydroxymethyl)-, and 2,4,6,8-tetrakis(hydroxymethyl)glycolurils gave novel bi-, tri-, and tetracyclic fused systems combining the glycoluril and sulfamide fragments. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2195–2199, November, 2007.     

Ion chromatographic separations of phosphorus species: a review

The aim of this paper is to review recent literature regarding the determination of phosphorus species by ion chromatography (IC), and describe the implementation of new developments in sample treatment and ion chromatography methodology for the analysis of these compounds. Ion-exchange methods using both carbonate/hydrogencarbonate and hydroxide selective columns in combination with self-regenerating membrane and solid-phase-based suppressors enable determination of phosphate down to ppb levels. New technology, particularly on-line electrolytic hydroxide generators and electrolytic self-regenerating suppressor devices, has allowed the use of elution gradients in both carbonate/hydrogencarbonate and hydroxide selective systems, improving sensitivity and reducing total analysis time for samples containing phosphate together with other inorganic anions. In addition to a review of these developments, optimization and application of chromatographic methods using reversed stationary phases and cationic and/or zwitterionic surfactants is also discussed.The objective of most of the IC methods developed for phosphorus species is the determination of phosphate and total phosphorus. Therefore, sample treatment and separation conditions specifically developed for this purpose are also described. In addition, application of IC to the analysis of other inorganic (reduced and condensed) and organic (phytates, alkyl phosphate, and phosphonates) phosphorus species is discussed along with methodology and relevant applications in water analysis and other miscellaneous fields.     

1,2-丙二醇合成丙酮醛反应催化剂的研究

通过固定床反应器考察了掺磷玻璃微珠银催化剂对１,２－丙二醇选择性氧化合成丙酮醛的催化性能。试验结果表明,在适宜的条件下,该催化剂对１,２－丙二醇的转化率达到９８％,对丙酮醛选择性达到了６９％。作者还就磷对催化剂选择性的提高给出了解释     

双羟甲基和双甲氧甲酰基取代的双(二硫代亚乙基)四硫代 富瓦烯的合成

合成了双羟甲基及双甲氧甲酰基取代的双(二硫代亚乙基)四硫代富瓦烯,给出了它们的质谱、核磁共振氢谱和碳谱,并讨论了影响反应的一些因素。