催化裂化汽油脱硫助剂的研究

中国80％成品汽油来自流化催化裂化（FCC）工艺,随着原料的多元化,大量中东高硫原油进入中国市场,硫质量分数过高的问题日益突出。     

钨酸催化氧化环己烯合成己二酸

以钨酸/有机酸性添加剂为催化体系, 在无有机溶剂、相转移剂的情况下, 催化30%过氧化氢氧化环己烯合成己二酸. 当钨酸∶有机酸性添加剂∶环己烯∶过氧化氢＝1∶1∶40∶176(摩尔比, 钨酸用量为2.5 mmol)时, 使用有机酸性添加剂考察钨酸的催化性能, 结果表明以钨酸/间苯二酚催化氧化环己烯的催化效果最优, 反应8 h时己二酸分离产率达90.9%、纯度为～100%; 而不使用有机酸性添加剂时, 己二酸分离产率只有72.1%, 产品纯度为96.2%. 当使用磺酸水杨酸、草酸、水杨酸为有机酸性添加剂时, 随反应时间的增加, 己二酸分离产率均升高, 但反应6 h以后, 己二酸分离产率随时间的变化不明显. 当磺酸水杨酸用量为2.5 mmol时, 己二酸分离产率和纯度均较高. 钨酸-磺酸水杨酸催化体系重复使用五次后, 己二酸分离产率仍可达到80.5%.     

Effect of Mobile Phase Components on the Separation of Polypeptides Using Carbon Dioxide-Based Mobile Phases

The effect of mobile phase modifier and additive on the chromatographic properties of various small polypeptides was explored under subcritical conditions. A polymeric column was used to separate various enkephalin analogs, bradykinin, and oxytocin using a carbon dioxide-based mobile phase with either an ethanol or a 2-methoxyethanol modifier. The role of the modifier was found to be secondary to that of the mobile phase additive. As progressively stronger acidic mobile phase additives were used, the peak profiles of the various polypeptides improved and retention decreased. Heptadecafluorooctanesulfonic acid was found to be the most useful additive for these types of solutes under near-critical conditions, while the potassium salt of heptadecafluorooctanesulfonic acid failed to elute any of the polypeptides. At low temperatures, pressure gradients with a carbon dioxide/ethanol/heptadecafluorooctanesulfonic acid ternary mobile phase produced reasonably good peak profiles with the polymeric column.     

Study of the Effect of Mobile Phase Additives on Retention in Reversed Phase HPLC Using Linear Solvation Energy Relationships

Linear solvation energy relationships (LSERs) were used to delineate which specific intermolecular interactions are responsible for changes in retention for a variety of well characterized analytes when acidic and basic additives were used in reversed phase HPLC. The effects of trifluoroacetic acid, triethylamine and a combination of trifluoroacetic acid and triethylamine on the LSERs were compared to those observed in the absence of additives. These effects were examined using four different mobile phase modifiers and five different stationary phases. Trifluoroacetic acid alone and in combination with triethylamine produced LSER regression coefficients nearly identical to those obtained with no additive present in the mobile phase. Triethylamine alone produced different LSER regression coefficients from the other systems unless the mobile phase contained trifluoroethanol as the mobile phase modifier, or the stationary phase consisted of a polymeric support.     

Ion-pair chromatography of bis (sodium-sulfopropyl) disulfide brightener in acidic copper plating baths

Quantitative analysis of the brightener component bis (sodium-sulfopropyl) disulfide (SPS) in acidic copper plating baths poses a real challenge due to the complex chemical matrix containing large amounts of Cu(II) ion and sulfuric acid together with other organic additives and additive decomposition products. We developed a new ion-pair chromatography method to analyze micro-molar amounts of SPS directly in plating bath samples without the need for sample pre-treatment. Addition of tetra-N-methylammonium cation as ion-pairing agent to a methanol-sulfuric acid-water eluent increases the retention time of the anionic SPS2- on a C18 column sufficiently to separate this compound from Cu(II) ion and additive by-products.     

酸性药物的反向电渗流高效毛细管电泳分离分析研究

以水杨酸、乙酰水杨酸为代表药物,采用十六烷基三甲基溴化铵（ＣＴＡＢ）为电渗流改向剂,考察了酸性药物在反向电渗流高效毛细管电泳体系中的分离行为,并对其中影响迁移时间、峰形及柱效的诸多因素进行了系统研究。研究结果表明,以阳离子表面活性剂作为电渗流改向剂的反向电渗流高效毛细管电泳体系能显著加快酸性药物的分析速度。对于ＣＴＡＢ与酸性药物相互作用导致峰形展宽、柱效降低的现象,可通过加入合适的有机添加剂（如β－环糊精或乙腈）加以改善。     

多糖衍生物手性固定相上采用酸性或碱性添加剂的流动相拆分β受体阻滞剂对映体

考察了多糖类手性固定相在含有酸性或碱性添加剂的流动相下高效液相色谱法拆分β受体阻滞剂对映体的效果。色谱条件: 流动相为10%～30%(体积分数,下同)乙醇-正己烷(含0.1%三氟乙酸)和10%～30%乙醇-正己烷(含0.1%三乙胺),流速1.0 mL/min,紫外检测波长254 nm。结果表明,在直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)衍生物手性固定相(Chiralpak AD和Chiralpak IA)上拆分β受体阻滞剂对映体,酸性添加剂的流动相体系与碱性添加剂的流动相体系相比,碱性添加剂的流动相的拆分效果比酸性添加剂的流动相要好。而在纤维素-三(3,5-二甲基苯基氨基甲酸酯)衍生物的手性固定相(Chiralcel OD和Chiralpak IB)上分离β受体阻滞剂,比较酸性添加剂的流动相与碱性添加剂的流动相的拆分效果,发现酸性添加剂的流动相条件下对映体的保留减弱,但对映体的选择性增大,特别是在Chiralcel OD上,酸性添加剂的流动相体系对对映体的选择性非常理想,而且随着流动相中酸性添加剂含量的增加,β受体阻滞剂对映体的分离效果更佳。     

Optimization of the LC enantioseparation of chiral pharmaceuticals using cellulose tris(4‐chloro‐3‐methylphenylcarbamate) as chiral selector and polar non‐aqueous mobile phases

The resolving power of a new commercial polysaccharide‐based chiral stationary phase, Sepapak‐4, with cellulose tris(4‐chloro‐3‐methylphenylcarbamate) coated on silica microparticles as chiral selector, was evaluated toward the enantioseparation of ten basic drugs with widely different structures and hydrophobic properties, using ACN as the main component of the mobile phase. A multivariate approach (experimental design) was used to screen the factors (temperature, n‐hexane content, acidic and basic additives) likely to influence enantioresolution. Then, the optimization was performed using a face‐centered central composite design. Complete enantioseparation could be obtained for almost all tested chiral compounds, demonstrating the high chiral discrimination ability of this chiral stationary phase using polar organic mobile phases made up of ACN and containing an acidic additive (TFA or formic acid), 0.1% diethylamine and n‐hexane. These results clearly illustrate the key role of the nature of the acidic additive in the mobile phase.     

Inversion or retention? Effects of acidic additives on the stereochemical course in enantiospecific Suzuki-Miyaura coupling of α-(acetylamino)benzylboronic esters

The stereochemical course of the stereospecific Suzuki-Miyaura coupling of enantioenriched α-(acetylamino)benzylboronic esters with aryl bromides can be switched by the choice of acidic additives in the presence of a Pd/XPhos catalyst system. Highly enantiospecific, invertive C-C bond formation takes place with the use of phenol as an additive. In contrast, high enantiospecificity for retention of configuration is attained in the presence of Zr(Oi-Pr)(4)·i-PrOH as an additive.     

Effect of the type and concentration of mobile phase additives on the separation of salbutamol sulfate enantiomers in supercritical fluid chromatography

The influence of a set of additives of various nature on the separation of salbutamol sulfate enantiomers by supercritical fluid chromatography on the stationary phase based on amylose tris(3-chloro-5-methylphenylcarbamate) is considered. The application of water and acidic additives does not lead to enantioseparation. The use of hexafluoroisopropyl alcohol as an additive allows separation to occur but leads to a strong distortion of the chromatographic peaks. The application of basic additives such as isopropylamine or ammonia provides a stable separation with high selectivity and resolution as well as with the symmetrical peak shape. The selectivity coefficient is surprisingly almost independent of the amine modifier concentration in the mobile phase.     

Effectiveness of cell adhesive additives in different supramolecular polymers

Supramolecular motifs in elastomeric biomaterials facilitate the modular incorporation of additives with corresponding motifs. The influence of the elastomeric supramolecular base polymer on the presentation of additives has been sparsely examined, limiting the knowledge of transferability of effective functionalization between polymers. Here it was investigated if the polymer backbone and the additive influence biomaterial modification in two different types of hydrogen bonding supramolecular systems, that is, based on ureido-pyrimidinone or bis-urea units. Two different cell-adhesive additives, that is, catechol or cyclic RGD, were incorporated into different elastomeric polymers, that is, polycaprolactone, priplast or polycarbonate. The additive effectiveness was evaluated with three different cell types. AFM measurements showed modest alterations on nano-scale assembly in ureido-pyrimidinone materials modified with additives. On the contrary, additive addition was highly intrusive in bis-urea materials. Detailed cell adhesive studies revealed additive effectiveness varied between base polymers and the supramolecular platform, with bis-urea materials more potently affecting cell behavior. This research highlights that additive transposition might not always be as evident. Therefore, additive effectiveness requires re-evaluation in supramolecular biomaterials when altering the polymer backbone to suit the biomaterial application.     

Valence stabilization of polyvalent ions during gamma irradiation of their aqueous solutions by sacrificial protection. III-Valence stabilization of Fe(II) ions by organic additives

Valence stabilization of polyvalent ions in gamma irradiated aqueous solutions is sometimes necessary in some chemical operations. In previous publications, valence stabilization of some polyvalent ions in solution upon gamma irradiation was achieved by using inorganic additives capable of interacting with the oxidizing or reducing species formed during water radiolysis. The results showed that the nature and duration of valence stabilization of Fe(II) depend on the concentration of the inorganic additives used. In the present work, a series of some organic additives has been used to investigate their capability in inducing valence stabilization of polyvalent iron ions, taken as an indicator, in aqueous acidic solutions when subjected to extended gamma irradiation. The results showed that the efficiency of valence stabilization depends on the amount and chemical structure of the organic additive used.     

甲烷生物催化氧化制甲醇——几种化学物质对Methylosinus trichosporium 3011甲醇累积的影响

本文报导了在 Methylosinus trichosporium 3011细胞反应液中加入一些化学物质对甲醇累积的影响。结果表明,Na~+抑制甲烷单加氧酶的活性。当 M.trichosporium 3011细胞反应液中含高浓度磷酸根时,只有很少量甲醇累积下来。EDTA 和 Na_2EDTA 甲醇累积的促进作用小于甲酸钠或甲酸的作用。但由于 EDTA 不仅可以抑制甲醇脱氢酶的活性,而且可以螯合 Na~+,而甲酸则可使 NADH 辅酶再生。因此,反应液中含有2mM EDTA 和20mM 甲酸时甲醇累积量最高。     

棉秆催化热解特性及动力学建模研究

通过不同添加剂处理棉秆的热重实验,分析NaOH、Na₂CO₃、Na₂SiO₃、NaCl、TiO₂、HZSM-5六种添加剂催化棉秆热解动力学特性,结合原料的组分分析,建立三组分独立平行一级反应热解动力学模型对试样热失重行为进行模拟,采用非线性最小平方算法求解热解动力学参数。研究发现,添加剂的加入改变了三组分动力学参数,在碱性添加剂作用下,纤维素和半纤维素热解活化能都有较大程度降低,且碱性越强,纤维素热解活化能越低,而半纤维素热解活化能越高;中性添加剂NaCl对纤维素和半纤维素热解活化能的影响不大;酸性添加剂使纤维素和半纤维素的热解活化能有所增大,但所有添加剂对木质素热解活化能的影响不明显。     

2种添加剂在电有机合成中的应用

通过电解实验分别考察了5个阴极电还原反应和1个阳极电氧化反应在加入添加剂前后电流效率和转化率的变化。所选择的6个反应可以分为2类,一类是原料以分子形式存在于电解液中的反应,另一类是原料以离子形式存在于电解液中的反应。实验间二硝基苯电还原制间苯二胺,3-甲基吡啶氧化制烟酸和邻硝基酚电还原制邻氨基酚(酸性条件下)属于前一类反应,加入添加剂后,它们的电流效率分别由原来的65.69%、28.00%和45.09%变为66.15%、28.45%和37.07%,说明添加剂对原料以分子形式存在的反应没有作用或有抑制作用。实验邻硝基酚电还原制邻氨基酚(碱性条件下),丁二酸的电解全盛和水杨酸电还原制水杨醛属于后一类反应,加入添加剂后,它们的电流效率分别从原来的49.37%、65.06%和24.55%提高到75.80%、78.60%和30.06%,说明添加剂能够提高原料以离子形态存在的反应的电流效率。     

Effect of inhibitors on carbon steel corrosion in foaming solutions

The corrosion behavior of carbon steel in PO-6TS-M foaming solution was studied. Several kinds of inhibiting additives were tested for their ability to reduce the corrosion rate of steel. The antipyrene additive to the foaming solution was shown to be the most effective in reducing corrosion rate of carbon steel. The optimum concentration of the inhibitor additive was determined.     

Manipulating Reaction Energy Coordinate Landscape of Mechanochemical Diaza-Cope Rearrangement

Chiral vicinal diamines, a unique class of optically-active building blocks, play a crucial role in material design, pharmaceutical, and catalysis. Traditionally, their syntheses are all solvent-based approaches, which make organic solvent an indispensable part of their production. As part of our program aiming to develop chemical processes with reduced carbon footprints, we recently reported a highly practical and environmentally-friendly synthetic route to chiral vicinal diamines by solvent-free mechanochemical diaza-Cope rearrangement. We herein showed that a new protocol by co-milling with common laboratory solid additives, such as silica gel, can significantly enhance the efficiency of the reaction, compared to reactions in the absence of additives. One possible explanation is the Lewis acidic nature of additives that accelerates a key Schiff base formation step. Reaction monitoring experiments tracing all the reaction species, including reactants, intermediates, and product, suggested that the reaction profile is distinctly different from ball-milling reactions without additives. Collectively, this work demonstrated that additive effect is a powerful tool to manipulate a reaction pathway in mechanochemical diazo-Cope rearrangement pathway, and this is expected to find broad interest in organic synthesis using mechanical force as an energy input.     

不同硅铝比ZSM-5分子筛作为助催化剂在渣油裂化中的应用

采用不同方法表征了硅铝比(SiO2/Al2O3)为33、266和487的质子型ZSM-5分子筛,并研究了ZSM-5分子筛作为助催化剂在渣油裂解中的应用。与USY分子筛基催化剂混合后,在固定流化床上,评价了ZSM-5分子筛助催化剂的催化裂化性能。研究发现,提高ZSM-5分子筛硅铝比,可以有效抑制混合催化剂对汽油烯烃的裂解,从而避免了汽油烷烃的大量损失。加入ZSM-5助催化剂后,伴随着液化气(LPG)产率的增加,异丁烷和异戊烷产率增加,这可能是由USY基催化剂和ZSM-5助催化剂的综合效应引起的。汽油烷烃和芳烃含量的变化,引起了汽油辛烷值的增加。高硅铝比ZSM-5分子筛(硅铝比为266和487)不仅可以显著改善汽油的辛烷值,而且有效避免了汽油的大量损失。催化汽油辛烷值的改善主要是由于高硅铝比ZSM-5分子筛具有适宜的芳构化和异构化活性,这些变化主要源于高硅铝比ZSM-5分子筛小的孔道直径和适宜的酸性。     

Catalyst,additive and counterion effects on the efficiency and enantioselectivity of copper-catalysed C–H insertion reactions of α-diazosulfones

Asymmetric copper-catalysed intramolecular C–H insertion reactions of α-diazosulfones in the presence of various group I salts are reported leading to substantial variation in reaction efficiencies and enantioselectivities. The borate additives NaBARF and KBARF were found to be the most effective additives for permitting highly enantioselective syntheses with short reactions times and high efficiency. Significantly, direct evidence of the critical role of the additive in enantioselective carbenoid reactions has been secured.     

Putrescine homologues control silica morphogenesis by electrostatic interactions and the hydrophobic effect

A systematic model study on the role(s) of putrescine homologues on silicification is presented and it is proposed that electrostatic forces between additive and silicic acid, and the hydrophobic behaviour of the additives are both important in silicification.