Synthesis,characterization and properties of methylaminocellulose

Homogeneously prepared tosylcelluloses (TC) with degrees of substitution (DS) of DS_Tos 0.1–1.8 were used as intermediates for the synthesis of methylaminocelluloses (MAC) by nucleophilic substitution with methylamine. TC with DS_Tos up to 1.1 were shown to be valuable intermediates for selective synthesis of MAC with DS_MA varying from 0.1 to approximately 1. No nucleophilic substitution was observed at higher DS_Tos. At the chosen reaction conditions (60 °C, 48 h) residual tosyl moieties remained unchanged and little hydrolysis took place. The samples obtained were characterized by means of elemental analysis, FTIR and ¹³C CP/MAS NMR spectroscopy. ¹³C CP/MAS NMR spectroscopy was found to be an efficient tool for quantification of DS_MA. Furthermore, the swelling behaviour in water was investigated and preliminary tests concerning the bilirubin adsorption capacity of MAC were carried out.     

Inorganic-organic hybrids of the p,p′-diphenylmethylenediphosphinate ligand with bivalent metals: a new 2D-layered phenylphosphinate zinc(II) complex

By reaction of Zn(CH₃COO)₂ with p,p′-diphenylmethylenediphosphinic acid in water a new inorganic-organic polymeric hybrid of formula [Zn(CH₂(P(Ph)O₂)₂)] has been synthesized and completely characterized. The X-ray analysis established that the structure consists of 2D-layered polymeric array, the 2D-sheets being built up through strong covalent linkages between the zinc metal and the oxygen donors of the phenylphosphinate ligand. The 2D-layers, which are featuring a mesh-net fashion, present voids of various dimensionality, up to 24-membered rings. The organic parts of the hybrid ligand, namely the phenyl rings, are shielding the inorganic skeleton of the layers, preventing the propagation of the polymer in the third dimension. No water molecules are present in the lattice, both of coordination and crystallization. Crystal data are: monoclinic, P2₁/c, a=11.840(2), b=9.646(9), c=12.516(5) Å, β=95.03(2), V=1423.9(15) Å³, Z=4. The solid material has been characterized by ³¹P MAS NMR spectroscopy and thermogravimetric analysis.     

N(nPr)4[B5O6(OH)4][B(OH)3]2 and N(nBu)4[B5O6(OH)4][B(OH)3]2: Clathrates with a diamondoid arrangement of hydrogen-bonded pentaborate anions

Single-crystal X-ray structure analyses of N(nPr)₄[B₅O₆(OH)₄][B(OH)₃]₂,1, and N(nBu)₄ [B₅O₆(OH)₄][B(OH)₃]₂,2, reveal that these materials are novel clathrates, the isotypic host structures of which are three-dimensional assemblies of hydrogen-bonded [B₅O₆(OH)₄]^– ionsand B(OH)₃ molecules. The assembly of only the pentaborate anions is a distorted (i.e., along [102] elongated) fourconnected diamond-related network. The N(nPr) ₄ ⁺ and N(nBu) ₄ ⁺ ions are trapped within the complex three-dimensional channel systems of the host frameworks. Both1 and2 crystallize monoclinically with space groupP2₁/c andZ=4. The cell constants are:1:a=13.592(5),b=12.082(2),c=17.355(6) Å, =106.60(2)° (298K);2:a=13.874(3),b=12.585(1),c=17.588(4) Å, =107.04(1)° (238 K). The results obtained by both¹¹B and¹³C MAS NMR spectroscopy are discussed. Thermogravimetric studies under a flowing inert-gas atmosphere suggest that water, stemming from polycondensation of the hydrous borate species, is released from the clathrates at ca. 443 K (1) and 398 K (2) before the decomposition of the organic cations starts at ca. 603 K (1) and 603 K (2).Author for correspondence. Supplementary Data relating to this article are deposited with the British Library as supplementary publication No. SUP 82172 (82 pages).     

Oxygen/nitrogen ordering in lanthanum new phase (La3Si8N11O4)

High-resolution ¹⁷O NMR spectra have been collected for crystalline samples of lanthanum new phase, La₃Si₈N₁₁O₄. In conjunction with previously published ²⁹Si and ¹⁵N spectra obtained for this phase, and in the light of the high-quality crystal structure data reported recently, a more detailed interpretation of the NMR spectra is presented than was possible in previous studies. The non-bridging oxygens in the structure are responsible for the single sharp peak seen in the ¹⁷O spectrum at 188 ppm; the remaining oxygens, occupying bridging sites shared with nitrogen, show up only weakly on the ¹⁷O spectrum as a broad diffuse band centered around zero ppm. The peak at −57.3 ppm on the ²⁹Si spectrum is believed to correspond to an overlap of [SiN₄] and [SiON₃] environments, with the −68.2 ppm peak corresponding to an [SiO₂N₂] environment.     

Ω型分子筛脱铝的核磁共振研究

在不同投料比（ＳｉＯ２／Ａｌ２Ｏ３＝１３．８，１９及２１）条件下，合成了三种Ω型分子筛原粉．对投料比为１３．８的原粉样品进行了四种不同方式的脱铝处理，即水热、ＳｉＣｌ４、ＥＤＴＡ和（ＮＨ４）２ＳｉＦ６处理，而形成了系列脱铝Ω型分子筛样品．对原粉及其脱铝样品进行了２９Ｓｉ和２７ＡｌＭＡＳＮＭＲ测试，确定出样品骨架硅铝比和铝在两种晶体学不等价Ｔ位上的占据比率，以探索四种脱铝方法的效果．实验结果与分析表明：在所有样品中，铝原子的占据具有择优Ｂ位的倾向；且铝在ＴＡ与ＴＢ位上的占据比率与合成条件有关；四种处理方式对Ω型分子筛的脱铝效果不尽相同．     

THF—FER沸石的系列研究—1．晶体结构稳定性

四氢呋喃（THF）-Na2O-SiO2-Al2O3-H2O体系水热合成的THF-FER沸石，经酸交 换-焙烧脱THF（Ⅰ）或焙烧脱THF-酸交换（Ⅱ）的不同方式处理，均可制得低钠H- FER沸石。经XRD，^27Al与^29Si MAS NMR,低温氮吸附等表征证明，通过1273K高温 的热处理和1073K饱和水蒸气下的水热处理，H-FER沸石骨架保持高度稳定。在高温 水蒸气作用下，Si(2Al）容易从骨架上脱离，而Si(1Al）则保持相对稳定，以（Ⅱ ）方法处理，制备的H-FER沸石在水热条件下易产生较多的硅差劲基缺陷。经高温 热和水热处理后，H-FER沸石孔道结构基本保持完美、开放。     

THF-FER沸石的系列研究—Ⅱ．模板剂分子THF的位置

用^13C HPDEC MAS NMR与热分析方法表征了在四氢呋喃（THF）-Na2O-SiO2- Al2O3-H2O体系中水热合成的高硅Na-THF-FER沸石、酸交换后的H-THF-FER沸石以及 吸附于Na-FER和H-FER沸石中的THF。结果证明，模板剂分子THF位于Na-THF-FER沸 石骨架的FER笼内，平衡骨架阳离子Na^+主要存在于十元环孔道；而吸附子FER沸石 中的THF仅处于十元环孔道中，合成样品中THF的化学位移与液态THF相比，向低场 移动，谱线明显变宽，表明THF分子与FER笼之间存在很强的相互作用。     

A new route for the functionalisation of wood through transesterification reactions

A novel transesterification reaction between acetylated maritime pine sapwood (Pinus pinaster Soland) and methyl benzoate (MB), in the presence of dibutyltin oxide (DBTO) as a catalyst, was performed. Reaction was confirmed by Fourier-transform infrared spectroscopy (FTIR) and ¹³C nuclear magnetic resonance cross-polarisation with magic-angle spinning (NMR CP MAS) analysis: signals corresponding to benzoylated wood were identified and, when transesterification was performed with ethyl trimethylsilylacetate (ETMSA), characteristic trimethylsilyl groups were detected. The acetyl/benzoyl exchange rate was found to increase with increasing amount of DBTO, temperature and reaction time and a concurrent deterioration of the woody material was evidenced.     

Studies on Natural CXN Zeolite： Modification, Framework De-alumination and Ion-exchange

A natural CXN zeolite (stilbite, type code-STI) discovered in China was modified with NH4^ exchange by using ammonium salt and calcinations (procedure Ⅰ), or with NH4 exchange followed by treatment with acid (procedure Ⅱ). The coordination state of Si and A1 atoms in the framework, the property of ion exchange, and the adsorption of the H-STI zeolite samples prepared by different modification procedure were investigated with XRD,EDX,^29Si and ^27Al MAS NMR, Ag^ ion exchange and Ne adsorption. The results of the investigations indicate that different procedure of the modification made variety on the distribution of the framework Si atoms and A1 atoms,the content of non-framework aluminum, and the blocking channels and the shielding effect to the positions of the exchangeable cations. The H-STI zeolite prepared by the procedure Ⅱ possesses high ion exchange capacity, open and perfect pore system, and high thermal stability.     

Direct Observation of Various Al Sites in SAPO-34by ^27Al Multiquantum(MQ) Magic Angle Spinning (MAS)NMR

The elegant 2D multiquantum (MQ) MAS NMR has been applied to investigate the coordination of Al atoms in SAPO-34.The results show that the effects of the template and /or water on the coordination of Al atoms are significant,which lead to the formation of various Al species.Up to four kinds of Al species are distinctly resolved.