偶氮二异丁腈测定

本文介绍了气量法测定偶氮二异丁腈含量。该方法操作简便,省时省力,准确度较好,精密度较高。     

偶氮二异丁腈生产工艺的研究

偶氮二异丁腈传统生产工艺不尽合理,通过对传统工艺进行改造、优化,开发出二步法偶氮二异丁腈生产新工艺。     

偶氮二异丁腈测定

本文介绍了气量法测定侧氮二异丁腈含量。该方法操作简便，省时省力，准确度较好，精密度较好。     

偶氮二异丁腈生产工艺改造的研究进展

我国偶氮二异丁腈生产企业的生产工艺不尽合理,本文通过对传统"三步法"改造的介绍,提出优化传统工艺的建设性意见.     

低含量偶氮二异丁腈的色谱定量分析方法研究

偶氮二异丁腈受热易分解,通过用气相色谱法定量分析偶氮二异丁腈分解产物异丁基自由基,达到对偶氮二异丁腈进行定量分析的目的,分析方法简单、快速、准确。采用气相色谱-质谱联用仪进行定性分析,通过气相色谱法分析建立w(偶氮二异丁腈)=0.002 01%~9.95%的工作曲线。结果表明,w(偶氮二异丁腈)与其分解产物异丁基自由基的峰面积成线性关系,相关系数为0.999;采用气相色谱法外标法进行定量分析,其分析结果的相对标准偏差为13%。     

分光光度法测定偶氮二异丁腈

本文采用分光光度法代替极谱法测定偶氮二异丁腈含量,通过对样品的对照测试,证明此法简单、快速、准确。完全符合生产中间控制对测定的要求,测定波长为350nm.在0.80%～1.40%的测定范围内,符合比耳定律。     

偶氮二异丁腈制备低密度不饱和聚酯树脂制品

以偶氮二异丁腈(AIBN)为发泡剂兼引发剂、CaCO3为成核剂制备了低密度不饱和聚酯树脂制品(LDUPRP)。以成型温度、AIBN用量和CaCO3用量作为三因素,设计L25(53)正交试验以确定制备LDUPRP的最佳配比和成型条件。结果表明:AIBN作为发泡剂适用于不饱和聚酯树脂(UPR)体系;LDUPRP的最佳制备条件为成型温度80℃、AIBN用量为树脂质量的2%、CaCO3用量为树脂质量的3%,此时制得的样品密度为0.452g/cm3,压缩强度达13.64MPa,比压缩强度为30.18MPa/(gcm-3),与硬质聚氨酯泡沫相近。红外光谱(FTIR)分析表明,AIBN引发UPR固化的结果与过氧化苯甲酸叔丁酯(TBPB)一致;丙酮萃取法和差示扫描量热(DSC)分析表明,AIBN用量为树脂质量的2%时树脂的固化度最高;样品断面分析表明,成核剂及其用量对泡孔形态有一定影响,不含CaCO3时形成狭长的泡孔,当CaCO3用量为树脂质量的7%时LDUPRP出现并泡现象。     

偶氮二异丁腈引发液态聚碳硅烷的交联研究

在偶氮二异丁腈(2,2′-azobisisobutyronitrile,AIBN)引发下,研究液态超支化聚碳硅烷(byperbranched polycarbosilane,HBPCS)的无氧热交联,考察交联温度、AIBN用量以及时间对交联反应及陶瓷产率的影响.结果表明:较高的温度可促进交联;AIBN用量越多越有利于交联,陶瓷产率先增加而后稳定,其最佳用量为1.0%2.0(质量分数,下同);随着交联时间延长,HBPCS的交联程度和陶瓷产率先增加而后保持不变.对于AIBN用量1.5%的体系,HBPCS经80℃交联6h后,其1 000℃下的陶瓷产率高达75%以上.此外,对最终陶瓷相组成进行表征,发现AIBN的引入能够有效抑制β-SiC的结晶.     

Al~(3+)/UV催化臭氧去除偶氮二异丁腈废水中CN~-的研究

研究Al3+/UV催化臭氧对偶氮二异丁腈废水中CN-的降解特性。分析了pH、Al3+投加量和O3浓度对Al3+/UV催化臭氧降解CN-的影响。探讨Al3+/UV催化臭氧工艺中光催化反应动力学特征。结果表明,当pH值为9.0、Al3+投加量为0.61 g·L-1和气相臭氧质量浓度为50~55 mg·L-1时,偶氮二异丁腈废水中CN-的降解效果较好。Al3+/UV催化臭氧工艺降解腈纶废水的反应符合类一级动力学反应,偶氮二异丁腈废水中的初始CN-值在600~1500 mg·L-1时,一级反应速率常数为0.03011~0.00651 min-1。所需水力停留时间为240 mim。     

Molecular Recognition of Water-soluble Pillar[n]arenes Towards Biomolecules and Drugs

The exploration of molecular recognition of synthetic macrocycles in aqueous media is significantly important since most biological functions, activities and processes take place in water. Pillar[n]arenes (n=5–10) have been recognized as a new generation of macrocyclic arenes; much attention has been devoted to their host-guest chemistry. This review summarizes the host-guest properties of water-soluble pillararenes towards biologically significant molecules and drugs. These water-soluble pillararenes are classified into three major classes according to the electric charges of hydrophilic groups at their portals: anionic pillar[n]arenes ( AP[n]s ), cationic pillar[n]arenes ( CP[n]s ), and neutral pillar[n]arenes ( NP[n]s ). The host–guest affinities, binding modes, binding selectivity, stimuli-responsiveness, as well as biomedical applications are comprehensively discussed.     

Pillar[n]arenes at the Chemistry-Biology Interface

Macrocyclic chemistry has provided chemists with a wealth of molecular ‘hosts’. Ever since resurgence in the field during the 1970s and 1980s these hosts’ similarities to natural structures, such the active sites of enzymes, have been noted. Latterly there has been great interest in the recently reported pillar[n]arenes. As if to underline the importance of these compounds, exciting applications are starting to emerge, from electrochemical sensors to antimicrobial agents. Novel uses appear destined to have an impact on clinical conditions from Alzheimer's disease to cancer treatment. In order to demonstrate the impact of pillar[n]arenes across the chemistry-biology interface this review will cover the current state of the art from biomimicry and analyte-specific detection to emerging clinical applications. Examples include pillar[n]arene-based ion channels, enzyme-responsive compounds, imaging agents, biofilm inhibiting derivatives, drug complexing and drug releasing systems.     

Pillar[n]arenes for Construction of Artificial Transmembrane Channels

Pillar[n]arenes have been intensively used during the last decade in supramolecular chemistry as host systems for guest recognition and self-assembly, toward functional materials and devices. They present electron-rich and tuneable size cavities, as well as reactive rims for further functionalization. Their unique pillar shape promotes pillar[n]arenes as molecular analogues of carbon nanotubes. For this reasons pillar[n]arenes have been embedded into membranes and used to construct artificial water, proton, ions and molecular channels. This review discusses the incipient developments of the first artificial channels based on pillar[n]arenes. We include also systems that integrate pillar[n]arenes as synthetic elements for the construction of selective pores of nanodevices for ion rectification.     

Self-Assembling Systems Based on Pillar[5]arenes and Surfactants for Encapsulation of Diagnostic Dye DAPI

In this paper, we report the development of the novel self-assembling systems based on oppositely charged Pillar[5]arenes and surfactants for encapsulation of diagnostic dye DAPI. For this purpose, the aggregation behavior of synthesized macrocycles and surfactants in the presence of Pillar[5]arenes functionalized by carboxy and ammonium terminal groups was studied. It has been demonstrated that by varying the molar ratio in Pillar[5]arene-surfactant systems, it is possible to obtain various types of supramolecular systems: host–guest complexes at equimolar ratio of Pillar[5]arene-surfactant and interpolyelectrolyte complexes (IPECs) are self-assembled materials formed in aqueous medium by two oppositely charged polyelectrolytes (macrocycle and surfactant micelles). It has been suggested that interaction of Pillar[5]arenes with surfactants is predominantly driven by cooperative electrostatic interactions. Synthesized stoichiometric and non-stoichiometric IPECs specifically interact with DAPI. UV-vis, luminescent spectroscopy and molecular docking data show the structural feature of dye-loaded IPEC and key role of the electrostatic, π–π-stacking, cation–π interactions in their formation. Such a strategy for the design of supramolecular Pillar[5]arene-surfactant systems will lead to a synergistic interaction of the two components and will allow specific interaction with the third component (drug or fluorescent tag), which will certainly be in demand in pharmaceuticals and biomedical diagnostics.     

Advanced Functional Materials Constructed from Pillar[n]arenes

Pillar[n]arenes are new generation of supramolecular macrocyclic host, which exhibit excellent host−guest recognition properties. In the last decade, functional materials constructed from pillar[n]arenes have been attracted more and more attention and displayed outstanding characteristics, such as stimuli-responsiveness, self-healing and adaptability. In this mini-review, we provide a survey of the pillar[n]arene-based literatures covering light-harvesting systems, functional hydrogels, and solid materials. It is anticipated that more and more pillar[n]arenes-based advanced materials with multi-functional properties will appear in the near future.     

柱[6]芳烃的合成及最新应用进展

柱芳烃作为一类新的大环芳烃主体化合物在主-客体化学中扮演着越来越重要的角色.作为柱芳烃家族中一员,柱[6]芳烃因其简便的合成、较大的柱状空腔和优秀的主-客体性质在吸附材料、药物传递、两亲性材料等领域展示了极好的应用前景.该文着重介绍了柱[6]芳烃的分子结构、合成策略、功能化、主-客体性质及其最新的应用研究进展.     

Surfactant Effect on the Physicochemical Characteristics of Solid Lipid Nanoparticles Based on Pillar[5]arenes

Novel monosubstituted pillar[5]arenes containing both amide and carboxyl functional groups were synthesized. Solid lipid nanoparticles based on the synthesized macrocycles were obtained. Formation of spherical particles with an average hydrodynamic diameter of 250 nm was shown for pillar[5]arenes containing N-(amidoalkyl)amide fragments regardless of their concentration. It was established that pillar[5]arene containing N-alkylamide fragments can form spherical particles with two different sizes (88 and 223 nm) depending on its concentration. Mixed solid lipid nanoparticles based on monosubstituted pillar[5]arenes and surfactant (dodecyltrimethylammonium chloride) were obtained for the first time. The surfactant made it possible to level the effect of the macrocycle concentration. It was found that various types of aggregates are formed depending on the macrocycle/surfactant ratio. Changing the macrocycle/surfactant ratio allows to control the charge of the particles surface. This controlled property will lead to the creation of molecular-scale porous materials that selectively interact with various types of substrates, including biopolymers.     

Pillar[5]arene-stabilized Plasmonic Nanoparticles as Selective SERS Sensors

We present here a simple procedure for the surface modification of plasmonic nanoparticles (NPs) with a cationic water-soluble ammonium pillar[5]arene (AP[5]A) in order to create selective surface-enhanced Raman scattering (SERS) spectroscopy based sensors. The strategy is based on a ligand exchange reaction between the AP[5]A and the stabilizing agent of the as-prepared plasmonic NPs. The approach could be applied to plasmonic nanoparticles either negatively charged, stabilized by citrate ions (Au spheres) or positively charged, stabilized by cetyltrimethylammonium bromide (Au and Au@Ag nanorods). The SERS performance of all systems was studied as a function of NP size and excitation laser line by using an analyte with no affinity towards the metal surface such as pyrene. The analytical enhancement factor (AEF) for the different systems was estimated between 0.55×10⁴ and 1.49×10⁵. Finally the synergistic effect of combining supramolecular chemistry and plasmonic NPs is demonstrated through SERS-based detection, in aqueous media, of molecules with no affinity towards a bare plasmonic substrate such as the contaminant pyrene or the biomolecule pyocyanin with nanomolar limit of detection.     

Calix[n]arenes. IV. Interaction of tert-Butylcalix[n]arenes with Cyclic Amines

p-tert Butylcalix[n]arenes 1 and 2 react with the cyclic amines 3 – 8 , 10 by proton transfer forming so-called „exo-complexes”︁ between the ammonium and phenolate groups. As well endocyclic as exocyclic amino groups are reactive. The nitroxyl radical 9 does not react with 1 or 2 by the proton transfer reaction. These results demonstrate that an interaction between the nitrogen atom of HALS-compounds, esp. compound 10 , with calix[n]arene hydroxylgroups is possible, but an interaction between the corresponding nitroxyl radicals with calix[n]arene hydroxylgroups does not occur.     

Hydroxyl Replacement in Calix[n]arenes

The synthetic methods by which the hydroxyl groups of calix[n]arenes have been formally dehydrated to afford xanthene derivatives, or have been replaced totally or partially by hydrogen, amino, halogen, alkyl, or mercapto groups are reviewed.