羧基

The methods determing the groups in the modified starch have been developed, that is acidimetry for the basicity of acidified starch, complexing titration for the substitution degree of carboxymethyl starch, and heat paste titration and carbonyl process respectively for the carboxyl and nitrogen of oxidized starch.

建立了以酸碱滴定测定酸化淀粉的碱量、络合滴定法测定羧甲基淀粉的取代度、热糊滴定和羟胺法测定氧化淀粉中羧基及羰基、消化定氮测定阳离子淀粉等几种变性淀粉的基团分析方法。

Therefore esterification crosslinked reactionbetween polyearboxylic acid and wood can be quantitatively determined.According toexperiment results of stereoscopic configuration choices by crosslinking agents,crosslinkingreaction between model of reaction intermediate and wood,and the intermediate characteristic incrosslinking reaction,crosslinking reaction intermediate was proofed.We can infercrosslinking reactions between polycarboxylicacid and wood want through a mechanism of twosteps reaction process,the first cyclic anhydrides were formed as intermediates by dehydratingbetween hydroxyls in polycarboxylic acids,second esters were occurred by substitution reactionbetween wood hydroxyls and cyclic anhydrides.

从而可全面定量表征木材与多元羧酸类化合物的酯化交联反应；依据交联剂立体构型选择性、反应中间体模型物与木材的交联反应和交联反应中间体的波谱特征实验结果，证实了交联反应中间体，因此可以推测：多元羧酸类化合物与木材化学组分的交联反应是经历两步反应的机理，首先多元羧酸中相邻羧基的羟基之间脱水形成五元环酸酐中间体，然后木材的羟基与酸酐发生亲核取代反应形成酯。

In all those complexes, no matter which conformation IDA assumes (mer- or fac-style), the two 0 atoms of 1N2O are both from carboxylic hydroxyl. However, by comparing the bond length, we can find that O(4) and O(2) atom is from different group in this complex, 0(4) atom from carboxylic hydroxyl, whereas, 0(2) from carboxylic carboxide.

值得注意的是：在这个双核配合物中，我们首次发现一种新颖的配位方式：IDA上与金属离子配位的三齿螯合原子是亚氨N原子、一个羧基上的羟基O原子和另外一个羧基上的羰基O原子。

The SERS spectra of isoquinoline and its six derivates 3 -isoquinolinecarboxylic hydrate (Ⅱ, 1-isoquinolinecarboxylic acid, methyl 3-isoquinolinecarboxylate, isocarbostyril, 5-hydroxy-isoquinoline and 1, 5-isoquinolinediol were obtained by mixing the chemicals with silver colloid.

应用SERS技术，我们获得了异喹啉及其六种衍生物3-羧基异喹啉(Ⅱ，1-基异喹啉，甲基-3-羧基异喹啉酸酯，1-羟基异喹啉，5-羟基异喹啉和1，5-二羟基异喹啉的喇曼光谱。

From the structural analysis of three praseodymium complexes, we could draw a conclusion that as the dentate arms of carboxyl group on ligands elongating, the coordination numbers of Pr and the coordination modes of ligands increase, and the mean distances between metallic atoms of metallic helices existing in these complexes augment.2. By altering 5-substituting group of isophthalic acid three series of lanthanide complexes 8～19 with 5-methylisophthalic acid and 5-nitroisophthalic acid have been prepared.

从得到的三个配体的镨配合物的结构分析可以看出，随配体的羧基齿臂的增长，Pr的配位数逐渐增大，配体的配位模式增多，配合物中存在的螺旋金属链中的金属间平均距离增大。2、通过改变间苯二甲酸配体的5位取代基，制备了5-甲基间苯二甲酸和5-硝基间苯二甲酸的三个系列稀土羧酸配合物8～19。

In complexes 8～16 synthesized by hydrothermal method, most of the ligands adopt multidentate coordination modes joining several lanthanide ions into high-dimensional coordination polymers. And changing of 5-substituting group on isophthalic acid has a little effect on the coordinated abilities of the meta-carboxyl groups.

水热法制备的配合物8～16中，配体多采取多齿配位模式桥连多个稀土离子，形成高维配位聚合物，同时由于羧基氧原子和稀土离子的强的键合力，间苯二甲酸的5位取代基的变化对间位羧基的配位能力的影响不大。

The hydrophobic core serves as a reservoir for water-insoluble drugs.Hence,these nanoparticles can be used as carriers for hydrophobic drugs.For the synthesis of cholesterol-modified glycol chitosan conjugates,a carboxyl group was initially introduced to cholesterol molecule using succinic anhydride,and then covalently coupled with the primary amino group of glycol chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride and N-hydroxyl succinimide.

本文采用二步反应将胆固醇接枝到乙二醇壳聚糖，首先将胆固醇进行羧基化，将胆固醇与琥珀酸酐反应生成胆固醇半琥珀酸酯，然后用1-乙基-3-(3-二甲基氨丙基)碳二亚胺盐酸盐与N-羟基琥珀酰亚胺作为偶联剂，将胆固醇半琥珀酸酯的羧基与乙二醇壳聚糖主链的氨基进行反应，得到胆固醇疏水改性乙二醇壳聚糖共聚物。

Several methods applied widely for synthesizing uronic acid are introduced, such as methods of one-step process and two-step process.

分别就糖醛酸的几种常用合成方法进行了介绍，即直接将羟甲基氧化成羧基的一步法和先将羟甲基氧化成甲酰基、再氧化成羧基的两步法。

The result indicated that MgO and α- methacrylic acid can together thicken epoxy, and the speed of thickening epoxy become quickly with the increasing content of MgO; when the ratio of MgO and α- methacrylic acid is 3:1, thickening epoxy have a better effect; the thickening mechanism: the terminal corboxyl group of α- methacrylic acid react with MgO, and it accompany with large numbers of heat, the heat can accelerate the reaction between the terminal corboxyl group with the secondary hydroxyl groups of epoxy, intermolecular hydrogen bonding which the water of above-mentioned formation result in and complex compound which format the metal atoms and carbonyl group complexing collective increase the viscosity of epoxy resin.

结果表明：MgO和α－甲基丙烯酸配合可增稠环氧树脂，随着MgO加入量的增加，环氧树脂增稠的速度加快；MgO与α－甲基丙烯酸为3：1时，增稠环氧树脂的效果较好；推测环氧树脂的增稠机理是α－甲基丙烯酸中的端羧基与氧化镁反应，放出热量促使其端羧基与环氧树脂中的仲羟基反应，上述反应生成水产生的氢键和羰基与氧化镁中的金属原子形成络合物共同导致环氧树脂的粘度增加。

A chemical reaction resulting in the formation of at least one ester product.

羧酶，羧基酶在羧化或脱羧反应中起催化作用的一种酶

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。