中国脂松香歧化反应机理的研究

研究中国脂松香在钯／炭催化剂作用下歧化反应的机理。发现其反应产物除去氢枞酸外，有８－二氢海松酸，８（１４）－二氢海松酸，８－二氢异海松酸，８（１４）－二氢异海松酸和８－二氢枞酸，及１３β－四氢枞酸，９β、１３β－四氢枞酸和１８－四氢枞酸等。同时，发现松香歧化反应速度高于湿地松松香，为歧化反应生产厂家选择歧化松香原料提供依据。     

水溶性钯-膦配合物催化松香加氢反应的研究

制备并表征了具有温控功能的膦配体脂肪醇聚氧乙烯醚亚磷酸邻苯二酚酯(FAPEPP),将其与钯的配合物用于催化松香加氢反应的研究,考察了反应时间、反应温度、氢气压力、催化剂用量等因素对反应的影响.在松香5g、m(松香): m(甲苯): m(水)1: 2: 2、氯化钯0.090%、n(氯化钯): n(膦配体)1: 10、氢气压力5MPa,反应温度160℃,反应时间3h的较佳工艺条件下,产物氢化松香中枞酸的质量分数小于1%,去氢枞酸的质量分数5.6%,符合GB/T 14020-2006国家标准;并对催化剂的重复使用性能进行了考察,催化剂相不经过处理直接重复使用5次后,产品氢化松香仍然符合国家标准中关于枞酸和去氢枞酸的指标要求.     

松香及其衍生物在胶粘剂中的应用

介绍了松香、改性松香及其衍生物在胶粘剂中的应用．应用于胶粘剂的松香有脂松香、未松香和浮油松香：改性松香包括它们的氢化、脱氢、歧化，聚合以及马来酸酐反应后的产物．松香衍生物包括松香和改性松香与各种醇反应生成的松香酯，氯化松香以及与其他物质的共聚物。松香及其衍生物在热熔胶和压敏胶中应用尤其广泛．     

松香催化加氢本征动力学研究

以脂松香为原料，RaneyNi为催化剂，200#油为溶剂，在150-180℃和氢压4-7MPa的条件下进行了松香催化加氢的本征动力学研究，根据实验结果筛选出合适的反应模型。即为吸附在催化剂表面上的氢分子和枞酸型树脂酸分子间的反应，产物二氢枞酸型树脂酸的脱附为速度控制步骤。     

杨梅不同部位单宁含量与结构研究

对杨梅的叶、枝和树皮的总酚含量与可溶缩合单宁含量进行了测定,并利用基质辅助激光解吸附飞行时间质谱(MALDI-TOFMS)详细研究了不同部位中缩合单宁的类型、聚合度及聚合物的分布情况。结果表明:树皮的总酚含量最高(43.56%),叶次之(34.69%),枝最低(18.53%);树叶的可溶缩合单宁含量最高(25.67%),皮次之(17.93%),枝最低(8.01%);3组分的缩合单宁都以(表)棓儿茶素-3-O-棓酸酯(EGCG/GCG)为基本结构单元的原翠雀定,且大部分聚合物的结构单元之间存在A型和B型两种连接方式,但其中叶和枝缩合单宁的聚合度要大于树皮。     

松香树脂酸乙烯酯的研究（Ⅱ）：松香树脂酸乙烯酯组成与结构的研究

研究了国立特级松香树脂酸乙烯酯的组成与各组份的分子结构。结果表明国产特级松香树酸乙烯酯的主要成分是枞酸乙烯酯,长叶松酸乙烯酯和去氢枞酸乙烯酯,三者间重量比为１３：３：２,其连续在羧基上的乙烯基在核磁共振谱图中呈现为很好的ＡＢＸ系统。     

PS-10对松香的浅色化作用机理初探

研究了浅色剂PS-10对松香的浅色作用机理.对反应前后松香物理指标及其化学组成分析发现随着PS-10用量增加、反应温度升高或反应时间延长,松香颜色变浅.加入PS-10反应后松香的枞酸型树脂酸含量由70.6%下降至18.8%,去氢枞酸从7.3%增加至30.6%,二氢树脂酸从0增加至12.2%.结果表明,PS-10对松香歧化反应起了催化剂的作用.同时,PS-10在松香脱色过程中,发挥了抗氧剂的作用,它的抗氧活性表现在酚羟基和硫原子上,酚羟基具有捕捉游离基的功能,而硫醚可以分解氢过氧化物,因而表现出分子内协同作用.     

去氢枞酸醇类香料酯的合成与表征

以去氢枞酸为原料,经去氢枞酸酰氯与醇类香料的O-酰化反应,合成得到去氢枞酸肉桂酯、去氢枞酸葑醇酯、去氢枞酸龙脑酯和去氢枞酸薄荷酯等4种去氢枞酸醇类香料酯,其中去氢枞酸肉桂酯和去氢枞酸葑醇酯为新化合物.目标产物的适宜合成条件为:反应时间10 h,反应温度95～100℃,反应物n(醇)∶n(酰氯)=1.2∶1.采用IR、UV、NMR和MS等方法对目标产物进行了结构表征.     

脱氢枞醇丁烯二酸单酯的合成及助焊性能研究

以脱氢枞酸和顺丁烯二酸酐为基本原料,先将脱氢枞酸经氢化铝锂还原为脱氢枞醇,再与顺丁烯二酸酐反应得到脱氢枞醇丁烯二酸单酯,并通过傅里叶红外光谱、核磁共振氢谱及质谱对产物进行表征。将脱氢枞醇丁烯二酸单酯配制成质量分数为25%的液体助焊剂,测试了助焊剂的物理性能,同时采用扩展率试验法研究了其对3种钎料Sn37Pb、Sn0.7Cu及Sn3.0Ag0.5Cu的助焊性能。结果表明,脱氢枞醇丁烯二酸单酯质量分数为25%的液体助焊剂在物理稳定性、干燥度、铜板腐蚀性以及焊后表面绝缘电阻等方面均符合相关标准要求,对3种钎料Sn37Pb、Sn0.7Cu及Sn3.0Ag0.5Cu的扩展率分别为76.6%、81.6%和75.3%,助焊活性均高于相同条件下的精制氢化松香助焊剂,并且钎焊Sn37Pb和Sn0.7Cu钎料时的焊点形貌规则,表面光亮无凹坑,明显优于精制氢化松香。     

蒎酸二酰基双去氢枞基双噁二唑的合成与表征

以歧化松香中提取的去氢枞酸为原料,经酰化得到去氢枞酸酰氯。以松节油的主要成分α-蒎烯为原料,经过蒎酮酸、蒎酸、蒎酸二乙酯得到蒎酸二酰肼。蒎酸二酰肼与去氢枞酸酰氯在相转移催化剂的作用下反应,得到N,N′-二去氢枞基取代蒎酸二酰肼,再经三氯氧磷脱水环合,得到蒎酸二酰基双去氢枞基双噁二唑。初步探讨合成条件,通过元素分析、IR、MS、1H NMR和13C NMR对所合成的化合物进行了结构表征。     

Chemistry and ecological significance of tannins

IntroductionChemicaldefenseisoneofanumberofwaysthatpIantsaredefendedfrommammalianherbivore.SuchchemicaldofenseinvolvestheelaborationandaccumuIationoforganicsubstanceswhenthepIanttissueiseaten.Thesubstancesmaybebittertasting,poisonous,oftenodour,orhaveantinutritionaIeffects.Thegreatmajorityofdeferentsubstancesaretheproductsofsecondarymetabolism.TheyrepresenttheammuIacationofendproductsfromarelativeIyIengthpathwayofenzyme-cataIyzedstepsinbio-synthesis.TheproductsarethenchannelIedwithinthepl…     

黑荆树皮单宁不同级分对水解酶的抑制作用

通过对黑荆树皮单宁进行醇沉纯化和溶剂萃取分级,可得到分子量分布范围不同的单宁级分。各级分对5种水解酶均表现出不同程度的抑制作用,具有一定的选择性。其抑制能力与抑制剂常数Ki值有关,分子量大的单宁级分,Ki值小,对酶活性的抑制作用大,同时,证明了黑荆树皮单宁对纤维素酶的抑制作用属于非竞争性抑制。     

水解单宁的微生物降解

单宁为高等植物的次生代谢产物,是相对分子质量为300到3 000的多酚类化合物,主要分为水解单宁和缩合单宁两大类。根据水解单宁结构特性的差异,又将其分为棓单宁和鞣花单宁。自然界中的某些微生物具有忍耐单宁的特性,甚至可以将单宁降解成具有一定生理或药理活性的小分子单宁或其衍生物。由于缩合单宁的分子结构复杂,对其微生物降解的研究远不及水解单宁深入。本文综述了近年来关于细菌和真菌降解棓单宁和鞣花单宁的研究情况,阐述了其降解机理,提出了微生物降解单宁需要解决的问题,可为单宁生物降解的进一步研究提供参考。     

植物单宁化学结构分析方法研究进展

植物单宁的各种性质,包括自由基清除能力和蛋白质结合能力等主要取决于其化学结构特别是分子质量的大小(聚合度)。因此对植物单宁化学结构的研究已成为近年来国内外相关研究的热点。本文综述了近10年来,国内外对植物单宁化学结构与分析方法的研究工作新进展。薄层色谱(TLC)和高效液相色谱(HPLC)技术可鉴定样品中所含单宁的结构类型;核磁共振(NMR)及质谱(MS)技术可对植物单宁纯化物进行结构测定;近年来发展起来的基质辅助激光解析离子化飞行时间(MALDI-TOF)质谱技术可对植物单宁混合物进行结构分析,并被证明是一种分析多分散的植物单宁聚合物的理想工具。     

植物单宁的营养学特性

结合植物单宁的化学性质，讨论了它们与蛋白质、酶、金属离子和多糖的作用。在此基础上，概述了植物单宁的抗营养性以及在食品和饲料加工中所采取的减弱单宁抗性的措施。     

Condensed tannins in Leucaena and their relation to psyllid resistance

Leucaena species and hybrids were examined to determine the relative content of condensed tannins and its relationship to susceptibility to defoliation by the Leucaena psyllid (Heteropsylla cubana). The interspecific Leucaena hybrid KX2 (L. leucocephala × L. pallida) was examined for variability of condensed tannin levels. A broad range of condensed tannin values were found which indicate potential for improved forage value through selection for KX2 trees with lower condensed tannin while maintaining psyllid resistance. A significant correlation was not found linking condensed tannins and psyllid resistance.     

Preparation and adsorption properties of macroporous tannin resins

1 Introduction Plant polyphenols are a large and diverse class of poly-atomic phenols which occur naturally in some parts of plants. Their molecular weight ranges from 500 to 3,000 g·mol–1. Plant polyphenols are abundant in nature and their production capacity is only second to that of cellulose, hemicellulose and lignin (Sun, 1988). Polyphenols can be divided into two kinds given their chemical constitution: hydrolysable tannin and condensed tannin (Song and Di, 2000). Benzene rings in th…     

Do tannins in leaves of trees and shrubs from African and Himalayan regions differ in level and activity?

Mature leaves of trees and shrubs from sub-humid tropical regions of Benin (Acioa barteri, Cassia sieberiana, Dialium guineense, Dichrostachys cinerea, Guiera senegalensis, Milletia thonningii, Piliostigma reticulatum) and arid and semiarid regions of Zimbabwe and Niger (Acacia holosericea, A. nilotica, Dichrostachys cinerea, Securidaca longepedunculata, Parinari cuvetelio, Ziziphus mucronata) in Africa, and from sub-tropical region in foot-hills of North-West Humid Himalayan range (Albizia stipulata, Bauhenia variegata, Cedrela toona, Celtis australis, Dendrocalamus hamiltonii, Grewia optiva, Leucocephala leucocephala, Morus alba, Papulus ciliata, Quercus incana, Q. semecarpifolia, Q. glauca, Q. serrata, Q. ilex, Robinia pseudoacacia, Salix tetrasperma) were analysed for crude protein, total phenols (TP), protein precipitation capacity (PPC) and operational activity of tannins (values are as mean ± SE). There was no significant difference in the crude protein values of forages obtained from the Himalayan and African region (15.2 ± 1.16 and 14.1 ± 1.19%, respectively), however the levels of TP and biological value of tannins as PPC were significantly higher for the African forages (TP 15.7 ± 4.27 vs 6.0 ± 1.0%; PPC 327.2 ± 113.6 vs 56 ± 15.9 mg bovine serum albumin precipitated/g). The operational activity of tannins expressed as mg protein precipitated per unit of phenols was also significantly higher in forages from the African regions (1.97 ± 0.47 vs 0.66 ± 0.17). For a small set of leaves from arid and semiarid zones of Middle East (Syria, A. cyanophylla; Israel, A. saligna) and India (Eugenia jambolana, Eucalyptus punctata, Prosopis cineraria and Shorea robusta) TP, PPC and tannin activity were closer to those for the African forages.This revised version was published online in November 2005 with corrections to the Cover Date.     

Chemical structures of the condensed tannins in the fruits of Diospyros species

The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1995     

Effects of pruning on the concentration of secondary metabolites in Colophospermum mopane leaves

Colophospermum mopane, commonly known as mopane, produces secondary metabolites during the growing season. However, there is still insufficient knowledge on the quantity of secondary metabolites and the effect of browsers on the concentration of secondary metabolites. A pruning experiment was conducted in the Musina Nature Reserve, Limpopo province, South Africa, to simulate the effect of browsers on the concentration of secondary metabolites in mopane leaves. The twigs from 40 selected experimental mopane trees were pruned back 50 mm from their tips using a hand shear. The total amount of leaf and shoot biomass removed from branches of selected experimental trees was less than 10%. Three independent samples composed of seven mopane leaves per 40 mopane trees were randomly collected from the canopies of experimental and control trees per sampling event. The dried leaves from each three independent samples were then mixed separately and a pooled sample of 10 g per treatment per sample cycle (55 d) was used for determination of total phenols (TP), condensed tannins (CT) and protein-precipitating tannins (PPT). Results showed that <10% pruning does not have an effect on the amount of secondary metabolites in the mopane leaves. The concentration of TP, CT and PPT increased during leaf flush in October and then declined as the leaves matured and aged. It is concluded that the amount of secondary metabolites in mopane leaves is not dependent on <10% pruning, but appeared to be associated with leaf growth stages. The ability of mopane to produce secondary metabolites has implications on the seasonal diet composition and distribution of browsers in mopane woodland.