添加甲酸+甲醛对草木樨青贮品质的影响

在刚收获及收获后经过8和30h晾晒的初花期草木樨青贮料中,加入甲酸+甲醛进行青贮。结果表明,草木樨低水分(DM为44.98%)青贮可以使青贮料的氨态氮含量降低,并保存更多的干物质、粗蛋白质和可溶性糖。甲酸+甲醛青贮能明显改善草木樨青贮料的发酵品质,即降低青贮料的氨态氮含量和保存更多的可溶性糖和粗蛋白质。晾晒8h组添加甲酸(2.0ml/kg)+甲醛(2.0g/kg)的效果最好;而晾晒30h组添加甲酸(3.0ml/kg)+甲醛(1.0g/kg)的效果最好。

对羟基苯甲醛缩邻氨基苯甲酸与汞的荧光猝灭反应及其应用

合成了一种新的席夫碱荧光试剂——对羟基苯甲醛缩邻氨基苯甲酸（HBAA）。研究了HBAA与汞离子的络合反应及其反应条件，HBAA390．0nm处有一强荧光峰，汞离子存在时，可与其形成稳定的络合物并使HBAA的荧光猝灭。利用该反应建立了荧光测定痕量汞的新方法，方法的线性范围为0—90．0μg／L，检出限为0．61μg/L。考察了40种常见共存离子的干扰影响，结果表明合成的HBAA试剂具有很高的选择性。该方法简便、快速，可用于矿泉水、自来水、河水中痕量汞的测定。

双核Cu(Ⅱ)-2,4-二羟基苯甲醛缩邻氨基苯甲酸Schiff碱配合物的合成、表征和晶体结构

The novel dinuclear copper(Ⅱ) complex with with N (2,4 dihydroxybenzalidene) o aminobenzoic acid ligand, [Cu(C14H9NO4)]2· 2H2O, has been synthesized and characterized by elemental analysis, IR, UV Vis and thermal analysis. Its crystal structure was determined by single crystal X ray diffraction techniques. The crystal belongs to monoclinic with space group P21/c. The cell parameters are: a=0.82510(11)nm, b=0.68870(9)nm, c=2.3007(3)nm, β =100.847(2)° , V=1.2840(3)nm3, Z=2, Dc=1.742Mg· m- 3, μ (MoKα )=1.723mm- 1, F(000)=684. The structure was refined to final R1=0.0267, wR2=0.0735. The complex molecule structure has dinuclear centrosymmetric dimeric structure in which a planar Cu2O2 core features. The ligand N (2,4 dihydroxybenzalidene) o aminobenzoic acid dianion is μ 2 tridentate, chelating one copper? ion via one nitrogen, one hydroxy oxygen atom and one carboxylate oxygen atom, and the hydroxy oxygen atom simultaneously coordinates to the other copper? ion of the dimer. In the structure the copper? ion rendered four coordination in a distorted square planar geometry structure. CCDC: 212695.

对二甲氨基苯甲醛缩邻氨基苯甲酸与锑(Ⅲ)的荧光猝灭反应及其应用

合成和鉴定了一种新的荧光试剂对二甲氨基苯甲醛缩邻氨基苯甲酸（DBAA）,并研究了DBAA与锑（Ⅲ）的荧光猝灭反应,同时探讨了将其应用于锑（Ⅲ）分析的最佳条件。实验表明,于10mL具塞比色试管中,依次加入0.5mL 1.0×10-6 mol/L DBAA乙醇溶液、2.0mL pH4.00的邻苯二甲酸氢钾缓冲溶液、3.0mL无水乙醇、一定量的锑标准溶液,室温反应20min,于激发波长λex=338nm,发射波长λem=402nm处测定,锑（Ⅲ）的质量浓度在0-60μg/L范围内与其对应的荧光猝灭程度呈良好的线性关系,相关系数为0.997 8,方法检出限为0.2μg/L。实验方法应用于自来水和湖水中痕量锑（Ⅲ）的测定,测定结果与火焰原子吸收光谱法（FAAS）基本一致,相对标准偏差（RSD,n=6）为2.6%-4.3%。

2-吡啶甲醛缩对氨基苯甲酸席夫碱Co(Ⅱ)、Cd(Ⅱ)配合物的合成及晶体结构

为了探究席夫碱及其配合物的空间结构,利用常温静置法合成了2-吡啶甲醛缩对氨基苯甲酸席夫碱的配合物1([Co L2(H2O)2]·5H2O)和配合物2({[Cd(L)(HL)(H2O)]·Cl O4·H2O}n(HL=2-吡啶甲醛缩对氨基苯甲酸;L=2-吡啶甲醛缩对氨基苯甲酸根)),并用X射线单晶衍射方法测得了二者的晶体结构.结果显示:配合物1为单斜晶系,空间群为P21/c;配合物2为正交晶系,空间群是Pbca.结构分析表明:配合物1中的Co2+离子采用六配位模式,分别与2个配体分子中的4个N原子和2个水分子中的2个O原子配位形成单核分子;配合物2为一维链状结构,每个Cd2+离子采用七配位模式,分别与HL中的2个N原子,L中的2个N原子、2个O原子以及水中的O原子进行配位.

多缩乙二醇桥连二对羟基苯甲醛缩邻氨基苯甲酸的合成

以多缩乙二醇桥连二芳醛与邻氨基苯甲酸的缩合合成了4种以对羟基苯甲醛、β—型氨基酸Schiff碱为端基的开链冠醚,并用IR、1HNMR和MS谱,确证了它们的结构。初步实验了其与金属离子的络合性能。

高效液相色谱法同时检测对苯二甲酸精制残渣中的八组分

采用高效液相色谱法,以弱极性阴离子交换键合固定相、磷酸盐缓冲溶液为流动相,UV 235 nm 检测,外标法定量,同时测定了对苯二甲酸精制残渣中的4-甲基苯甲醇,对甲基苯甲醛,4-羧基苯甲醛,苯甲酸,对甲基苯甲酸,对苯二甲酸,邻苯二甲酸和间苯二甲酸的含量,其回收率均在97.1%～105.4%之间,变异系数小于3.36%,相关系数为0.99163。

香草醛缩邻肼基苯甲酸的合成及其与银的荧光猝灭反应

合成了一种新的荧光试剂3-甲氧基-4-羟基苯甲醛-2-肼基苯甲酸(香草醛缩邻肼基苯甲酸),并用红外光谱法及元素分析法对其分子结构作了验证。试验发现:在pH 5.1的乙酸盐缓冲介质中,上述新试剂在激发波长为308.8 nm时,在476.8 nm波长处出现发射荧光峰,而当在此条件下加入银离子时,由于两者相互反应生成络合物而导致试剂发生荧光猝灭现象,其荧光强度的减弱程度(△F)与银离子的质量浓度在3.0～160μg·L^(-1)范围内呈线性关系。测得此反应对Ag^+离子的检出限(3S/N)为0.28μg·L^(-1)。据此,提出了测定痕量银的新方法。用标准加入法测得方法的回收率在98.3%～103.3%之间。

乙醛酸合成的研究

乙醛酸，别名甲醛甲酸，是最简单的酮酸，有醛和酸的性质，通常分布于未成熟的水果及某些动物组织的体液中，广泛用于合成清漆原料、香料、医药、染料、塑料、工业化学品的中间体，也可用于生产口服青霉素、香兰素、乙基香兰素和尿囊素等产品。目前合成乙醛酸的方法有：乙烯氧化法、乙醇酸转化法、乙二醛氧化法、二氧化酸化、

乙醛酸生产工艺及应用前景

乙醛酸，白色晶体，别名甲醛甲酸，英文名为Glyoxylic acid(简称GA)，分子式为C2H2O3，结构式为CHO—COOH是最简单的醛酸，有醛和酸的性质，能与水混溶，微溶于乙醇、乙醚，不溶于酯类、芳香族类溶剂，在水溶液中以水合乙醛酸的形式存在，其水溶液在空气中非常稳定。通常分布于未成熟的水果及某些动物组织的体液中，是一种重要的化工原料和生化试剂，广泛用于合成清漆原料、香料、医药、染料、

Photocatalytic aerobic oxidation of toluene and its derivatives to aldehydes on Pd/Bi_2WO_6

The selective oxidation of toluene and its derivatives is extremely important in the chemical industry.The use of photocatalysis in organic synthesis has attracted considerable attention among synthetic chemists because of its ＂green＂ environmental characteristics.In this study,nanoscale Bi_2WO_6with a flower-like morphology was found to be a highly efficient photocatalyst in the catalytic oxidation of toluene and its derivatives using O_2 as the oxidant.The loading of Pd nanoparticles as a cocatalyst onto the flower-like Bi_2WO_6 was found to produce a significant enhancement in the catalytic activity.Mechanistic investigation showed that the superior performance of Pd/Bi_2WO_6 could be attributed to the improvement of both the reductive and oxidative abilities of Bi_2WO_6 by the loading of the cocatalyst.

Studies on the Chemical Components of Clematis chinensis

Two novel compounds, clemaphenol A and dihydro-4-hydroxy-5-hyroxymethyl-2(3H)-fura-none were isolated together with eight known compounds, isoferulic acid, b-sitosterol, daucosterol, 5-hy-droxymethyl-2-furancarboxaldehyde, 5-hydroxy-4-oxo-pentanoic acid, palmitic acid, linoleic acid and anemonin from the root of Clematis chinensis Osbeck.

One‐step aldol condensation reaction of dimethoxymethane and methyl acetate over supported Cs/ZSM‐35 zeolite catalysts

This study was performed for the development of a green and promising approach for the synthesis of methyl acrylate and acrylic acid by a one‐step aldol condensation reaction of dimethoxymethane and methyl acetate over cesium oxide‐supported on ZSM‐35 zeolite catalysts; the effect of base sites as well as acid sites on the aldol condensation reaction was studied in detail. It was found that base sites were harmful for aldol condensation due to their failure in catalyzing the decomposition of dimethoxymethane precursor into formaldehyde, whereas the acid site was indispensable for the reaction to proceed. This reaction cannot take place without an acid site. Although acid sites in H‐form of the zeolite（HZSM‐35） are indispensable for the aldol condensation reaction, not all of them tend to favor this reaction. A strong acid catalyzes methanol‐to‐olefin‐like reactions resulting in hydrocarbon byproducts, which are finally transferred to hard coke. Medium strong acids and weak acids are great candidates for the target aldol condensation reaction with high activity and selectivity. A γ‐Al2O3 sample with abundant weak‐strength Lewis acid sites, together with a few medium‐strong‐strength acid sites, performs well with a high activity and considerable stability during the synthesis of methyl acrylate and acrylic acid.

Brφsted-acidic ionic liquids as efficient catalysts for the synthesis of polyoxymethylene dialkyl ethers

Acetalation of formaldehyde(HCHO)with dialkyl formal or aliphatic alcohol to prepare polyoxymethylene dialkyl ethers(RO(CH2O)nR,n≥1)catalyzed by Br?nsted‐acidic ionic liquids has been developed.The correlation between the structure and acidity activity of various ionic liquids was studied.Among the ionic liquids investigated,1‐(4‐sulfonic acid)butyl‐3‐methylimidazolium hydrogen sulfate([MIMBs]HSO4)exhibited the best catalytic performance in the reaction of diethoxymethane(DEM1)with trioxane.The influences of ionic liquid loading,molar ratio of DEM1to HCHO,reaction temperature,pressure,time,and reactant source on the catalytic reaction were explored using[MIMBs]HSO4as the catalyst.Under the optimal conditions of n([MIMBs]HSO4):n(DEM1):n(HCHO)=1:80:80,140°C,and4h,the conversion of HCHO and selectivity for DEM2?8were92.6%and95.1%,respectively.The[MIMBs]HSO4catalyst could be easily separated and reused.A feasible mechanism for the catalytic performance of[MIMBs]HSO4was proposed.

Exclusively catalytic oxidation of toluene to benzaldehyde in an O/W emulsion stabilized by hexadecylphosphate acid terminated mixed-oxide nanoparticles

A series of hexadecylphosphate acid(HDPA) terminated mixed-oxide nanoparticles have been investigated to catalyze the oxidation of toluene exclusive to benzaldehyde under mild conditions in an emulsion of toluene/water with the catalysts as stabilizers. With the HDPA-Fe2 O3/Al2 O3 as the basic catalyst, a series of transition metals, such as Mn, Co, Ni, Cu, Cr, Mo, V, and Ti, was respectively doped to the basic catalyst to modify the performance of the catalytic system, in expectation of influencing the mobility of the lattice oxygen species in the oxide catalysts. Under normally working conditions of the catalytic system, the nanoparticles of catalysts located themselves at the interface between the oil and water phases, constituting the Pickering emulsion. Both the doped iron oxide and its surface adsorbed hexadecylphosphate molecules were essential to the catalytic system for excellent performances with high toluene conversions as well as the exclusive selectivity to benzaldehyde. Under optimal conditions, ~83% of toluene conversion and >99% selectivity to benzaldehyde were obtained, using molecular oxygen as oxidant and HDPA-(Fe2 O3-Ni O)/Al2 O3 as the catalyst. This process is green and low cost to produce high quality benzaldehyde from O2 oxidation of toluene.

Enzyme‐like mechanism of selective toluene oxidation to benzaldehyde over organophosphoric acid‐bonded nano‐oxides

The completely selective oxidation of toluene to benzaldehyde with dioxygen,without the need touse H_(2)O_(2),halogens,or any radical initiators,is a reaction long desired but never previously successful.Here,we demonstrate the enzyme‐like mechanism of the reaction over hexadecylphosphateacid(HDPA)‐bonded nano‐oxides,which appear to interact with toluene through specific recognition.The active sites of the catalyst are related to the ability of HDPA to change its bonding to theoxides between monodentate and bidentate during the reaction cycle.This greatly enhances themobility of the crystal oxygen or the reactivity of the catalyst,specifically in toluene transformations.The catalytic cycle of the catalyst is similar to that of methane monooxygenase.In thepresence of catalyst and through O_(2)oxidation,the conversion of toluene to benzaldehyde is initiatedat 70°C.We envision that this novel mechanism reveals alternatives for an attractive route to designhigh‐performance catalysts with bioinspired structures.

OPA-FMOC在线柱前衍生高效液相色谱法测定不同产地燕窝中氨基酸含量

通过邻苯二甲醛-9-芴甲基氯甲酸酯(O-phthalaldehyde-9-fluorenylmethyl chloroformate,OPA-FMOC)柱前衍生高效液相色谱法,优化得到快速检测燕窝氨基酸的方法,并对10种不同来源燕窝中的氨基酸进行了定性和定量分析。结果表明,该法在14 min内可完成对22种氨基酸的分析,且在5~200 nmol/m L浓度范围内决定系数R2均大于0.998,检出限0.4~4 nmol/m L,回收率80%以上。该方法简便快速,灵敏度高,对高蛋白质食品中氨基酸的快速测定具有借鉴作用。

Methanol oxidation over shell-core MOx/Fe2O3（M = Mo, V, Nb） catalysts

We present a comparison of Mo, V and Nb oxides as shell materials atop haematite cores used for selective methanol oxidation. While Mo and V both yield high selectivity to formaldehyde, Nb does not. Very different reactivity patterns are seen for Nb, which mainly shows dehydrogenation (to CO) and dehydration (to DME), indicating the lack of a complete shell, while Raman spectroscopy shows that the Mo and V formation process is not followed by NbOx. We suggest this is due to the large differences in mobility within the solid materials during formation, NbOx requiring significantly higher (and deleterious) calcination temperatures to allow sufficient mobility for shell completion.

Tiny pollutant emissions of a dimethyl ether fuelled engine

Emissions of dimethyl ether(DME) fuelled engines were investigated by orthogonal experiments on a ZS195 diesel engine.The study mainly focused on the tiny pollutant emissions of formaldehyde(CH2O),methyl formate(CH3OCHO) and formic acid(HCOOH).The presence of CH2O,CH3OCHO and HCOOH are proved in the exhaust by gas chromatograph and Fourier transform infrared spectroscopy.The analysis of variance results indicate that the fuel delivery advance angle is the most important factor for CH2O emission.The fuel delivery advance angle and the interaction of injection pressure and nozzle diameter are considerable factors for unburned hydrocarbon(UHC) emission.The mechanism forming tiny pollutants,primarily through CH2O formation,is suggested to be similar to the mechanism forming UHC by DME partial oxidation existing in crevices and boundary zones,and is verified via DME combustion simulation of a multizone chemical kinetic model.

Effect of CO2 on oxidation of p-xylene in acetic acids/CO2

The oxidation of p-xylene to terephthalic acid with molecular oxygen in acetic acids modified carbon dioxide over Co/Mn/Br catalyst was studied in a batch reactor. The results showed that the oxidation of p-xylene to terephthalic acid was severely inhibited when carbon dioxide exceeded a certain amount, the conversion of p-xylene decreased rapidly from 100.0% to 3.3% and the yield of terephthalic acid dropped from 42.6% to trace. Whereas the oxidation processes of p-Tolualdchyde to p-Toluic acid and 4-Carboxybenzaldehyde to tcrcphthalic acid were improved when a relative small amount of CO2 v/as added, Further investigation found that this negative effect may be caused by multiphase reactions emerging.