悬浮液进样火焰原子吸收光谱法测定豆米类粮食中镁

将样品磨细配制成悬浮液,并对悬浮剂的选择及化学干扰的消除进行了考查。为消除化学干扰，取适量悬浮液，加入La3+溶液制成试液。将试液喷入空气-乙炔火焰，以空白溶液为参比，用工作曲线法进行测定。测定结果与灰化法一致，相对误差小于±1.3％。方法简便、快速、准确。     

火焰原子光谱法测定中成药丸中钙镁锌

用悬浮液技术处理中成药丸样品，将样品烘干、粉碎、过筛、悬浮于琼脂溶液中制成悬浮液。以Sr^2 溶液作为钙、镁的释放剂，以吸收法测定镁、锌，以发射法测定钙。对样品悬浮液的稳定时间、干扰、试液与空白溶液粘度的一致性及线性范围进行了考察。测定结果的相对标准偏差小于1．7％，加标回收率为96．6％～102．6％。     

悬浮液进样-火焰原子发射光谱法测定豆米中的钾和钙

将悬浮液进样技术应用于火焰原子发射光谱法,建立了测定豆米类粮食中钾、钙的快速分析方法。对悬浮剂的选择、干扰的消除、线性范围及检出限进行了考查。将样品粉碎、制成琼脂（米类）或琼脂－邻苯二甲酸二丁酯豆类）悬浮液,取适量样品悬浮液加入适量琼脂及释放剂Ｌａ（Ⅲ）或消电离剂ＮａＣｌ 溶液配制成试液。本方法的测定结果与灰化法－火焰原子吸收法一致,ＲＳＤ＜ ３．３％ ,钾、钙的检出限质量浓度分别为０．０１２ ｍ ｇ／Ｌ、０．０４１ ｍ ｇ／Ｌ。     

悬浮液进样-火焰原子吸收光谱法测定中草药中的微量铜

将悬浮液进样技术应用于火焰原子吸收光谱法,建立了快速测定中草药中微量铜的新方法。将样品磨细,制成悬浮液,喷入空气－乙炔火焰,以空白溶液为参比,用氘灯进行背景和扣除,以标准加入法测定。测定结果与灰化法一致,两种方法的相对误差小于±３．６％,ＲＳＤ小于２．５％,检出限为０．０５７ｍｇ／Ｌ。     

测定润滑油添加剂中钙钡的乳浊液进样-火焰原子发射光谱法

将乳浊液进样技术应用于火焰原子发射光谱法 ,建立了测定润滑油添加剂中钙和钡的灵敏、快速分析方法。对乳化剂的选择、化学干扰的消除、空白溶液的选择及检出限进行了考察。将样品的苯溶液用乳化剂OP乳化成乳浊液 ,取适量样品乳浊液加入适量琼脂溶液及释放剂配制成试液 ,喷入火焰 ,用标准加入法测定。该法的测定结果与灰化 -火焰原子发射光谱法一致 ,相对误差小于±2.9 %,t检验表明两种方法之间无显著性差异。方法的相对标准偏差小于2.7%,检出限:钙0.12mg/L、钡0.99mg/L。     

火焰原子吸收光谱法测定猪肝中铜铁锌

用悬浮液技术及非完全消化法分别处理猪肝样品,建立了悬浮液技术和非完全消化-火焰原子吸收光谱法快速测定猪肝中铜、铁、锌的分析方法。试验表明,在悬浮液中加入适量盐酸可显著提高被测元素的吸光度,试液的粘度与空白溶液的一致,无背景吸收干扰。对非完全消化法样品处理条件、悬浮液的稳定时间及酸的影响进行了考察。相对标准偏差小于4.0%,测定结果与灰化法一致,相对误差小于±1.8%(悬浮液法),±2.7%(非完全消化法)。     

试样非完全消化-火焰原子吸收光谱法测定清漆中锰锌

将非完全消化技术应用于火焰原子吸收光谱法测定了清漆中锰、锌。用高氯酸-硝酸混合酸（1＋3）消解样品，用乳化剂吐温-80消解产物而配制成均匀、透明的样品溶液，用工作曲线法测定。对消解溶剂及乳化剂进行选择，对化学干扰、混合酸、介质、试液与空白溶液粘度一致性及背景吸收干扰进行了考察。测定结果的RSD小于3．9％，加标回收率98．2%-102．9％，方法简便。     

非完全消化悬浮液进样火焰原子光谱法测定木耳中钾铜锌

将非完全消化法与悬浮液进样技术相结合处理木耳样品 ,即在加热下用浓硝酸消解样品 ,使绝大部分样品组分进入溶液 ,再加入乳化剂OP溶液及琼脂溶液将极小部分的不溶物悬浮成悬浮液 ,用吸收法测定铜、锌 ,以发射法测定钾。建立了测定木耳中钾、铜和锌的快速火焰原子光谱法。工作曲线法的测定结果与灰化法一致 ,相对误差小于± 2 .6% ,t检验表明此法与灰化法之间无显著性差异。方法简便、快速、准确     

悬浮液进样-火焰原子光谱法测定烟叶中的钾锰

用悬浮液技术处理烟叶样品 ,即将样品烘干、粉碎、过筛 ,并悬浮在 1 .5g L琼脂溶液中制成均匀的悬浮液。以钙作为锰的释放剂和以钡作为钾的消电离剂。用工作曲线法测定 ,以火焰原子发射法 (FAES)测定钾 ,以火焰原子吸收法 (FAAS)测定锰。建立了快速测定烟叶中钾、锰的FAS法。对化学干扰、介质的影响及检出限进行了考察。测定结果的相对标准偏差 <2 .4% ,测定结果与灰化法一致 ,相对误差 <± 2 .5 %。     

非完全消化—悬浮液进样—火焰原子光谱法测定蘑菇中钾、镁、锌

将非完全消化法与悬浮液进样技术相合处理蘑菇样品，即先用浓HNO3低温消解样品至溶液呈透明，再用琼脂溶液悬浮极少量不溶物，制成样品溶液。分别以Sr^2 溶液和NaCl溶液作为测定镁、钾的释放剂和消电离剂。以原子吸收光谱法测定镁、锌，以原子发射光谱法测定钾。对样品处理方法、干扰、线性范围及检出限进行了考察。建立了快速测定蘑菇中钾、镁、锌的火焰原子光谱法。相对标准偏差小于2.8%，加标回收率为97.9%-101.6%。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.