Novel biodiesel production technology from soybean soapstock

This paper describes an attractive method to make biodiesel from soybean soapstock (SS). A novel recovery technology of acid oil (AO) from SS has been developed with only sulfuric acid solution under the ambient temperature (25 +/- 2 degrees C). After drying, AO contained 50.0% FFA, 15.5% TAG 6.9% DAG 3.1% MAG 0.8% water and other inert materials. The recovery yield of AO was about 97% (w/w) based on the total fatty acids of the SS. The acid oil could be directly converted into biodiesel at 95 degrees C in a pressurized reactor within 5 hours. Optimal esterification conditions were determined to be a weight ratio of 1 : 1.5 : 0.1 of AO/methanol/sulfuric acid. Higher reaction temperature helps to shorten the reaction time and requires less catalyst and methanol. Ester content of the biodiesel derived from AO through one-step acid catalyzed reaction is around 92%. After distillation, the purity of the biodiesel produced from AO is 97.6% which meets the Biodiesel Specification of Korea. The yield of purified biodiesel was 94% (w/w) based on the total fatty acids of the soapstock.

西藏产雪莲花的化学成分研究

本学位论文报道了作为传统藏药材广泛使用的西藏产雪莲花化学成分的研究。论文由五章组成，第一章是三种西藏产雪莲花的化学成分的系统分离纯化和结构鉴定；第二章为西藏产雪莲花化学成分的液-质及串联质谱联用分析；第三章提出了以HPLC和TLC为检测方法的雪莲花药材质量标准草案；第四章给出了对西藏产雪莲花挥发油化学成分的气-质联用分析结果；第五章概述了雪莲花的化学成分及药理研究进展。 第一章包括三个部分。第一部分报道了绵头雪莲花(Saussurea laniceps Hand.-Mazz.)全草乙醇提取物化学成分的分离鉴定。采用正相硅胶柱层析及凝胶柱层析等分离方法，从西藏产绵头雪莲花的乙醇提取物中共分离鉴定出15个化合物。其中11个化合物为首次从该植物中分离得到，当中2个化合物系在凤毛菊属植物中首次发现。第二部分报道了水母雪莲花(Saussurea medusa Maxim.)全草乙醇提取物的化学成分。采用正、反相硅胶柱层析及凝胶柱层析等分离方法，共分离鉴定出15个化合物，其中1个为新化合物，另有4个化合物为首次从该植物中分离得到。新化合物结构通过质谱和一维及二维核磁共振等波谱解析方法及碱水解反应确定为巴豆酰基-高车前苷(M-7)。第三部分报道了三指雪莲花 (Saussurea tridactyla Sch.-Bip. ex Hook. f.)全草乙醇提取物的化学成分。采用正相硅胶柱层析及凝胶柱层析等分离方法，共分离鉴定出7个化合物，其中1个化合物为首次从该植物中分离得到。 第二章也包括三个部分。首先是采用液-质联用(HPLC-DAD-ESI-MSn)分析方法，对7个西藏不同产地的三指雪莲花化学成分进行了分析，通过与标准品的 UV和MS数据比较，共鉴定出14个峰，并对其中8个共有成分进行了定量测定。其次是关于八种西藏产雪莲花化学成分的液-质联用(HPLC-DAD-ESI-MSn)分析，通过与标准品的UV和MS数据比较，共鉴定出15个峰，并对其中8个共有成分进行了定量检测。最后通过对八种西藏产雪莲花主要化学成分的多级串联质谱(ESI-MSn)分析，快速、灵敏地鉴定出10个黄酮和3个香豆素化学成分。 第三章同样包括三个部分。首先是以绵头雪莲花中主要香豆素成分东莨菪素和伞形花内酯为对照品，通过TLC定性检测和HPLC含量测定，草拟出较严谨的药材质量标准。其次是将绵头雪莲花、三指雪莲花和雪兔子作为一个药材看待，草拟了以东莨菪素和伞形花内酯的TLC检测为指标的药材质量标准。最后是针对水母雪莲花，以主要黄酮成分芹菜素-7-O-b-D-葡萄糖苷为对照品作TLC检测，并草拟出该药材的质量标准草案。 第四章报道了西藏产雪莲花挥发油的化学成分分析。采用传统水蒸气蒸馏法分别从八种雪莲花全草中提取挥发油，利用气相色谱-质谱联用技术分别从水母雪莲花、绵头雪莲花、槲叶雪莲花、云状雪兔子、拉萨雪兔子、小果雪兔子、雪兔子和三指雪莲花中分别鉴定出83、83、56、34、21、20、24和20个化学成分，分别占其挥发油总量的70.7%、76.0%、82.2%、55.4%、49.7%、70.4 %、76.2%和 76.7%。 第五章为综述，总结和概括了雪莲花的化学和药理研究进展。 The dissertation reports the investigation of the chemical constituents of the genus Saussurea. Quite a lot of species in this genus are traditional Tibetan medicinal plants, and hence have been widely used in traditional Tibetan medicine. This dissertation consisted of five chapters. The first chapter is on the chemical constituents of three Saussurea plants. The second section is about the analysis of chemical constituents of Saussurea plants using HPLC-MS and ESI-MS/MS. In the third chapter, we proposed quality-control standards for the Genus Saussurea based on TLC (thin layer chromatography) and HPLC. The fourth chapter is about chemical compositions of the essential oil from the whole plant of Saussurea plants. The last chapter reviews the research progress of the Genus Saussurea. The first chapter consists of three parts. The first part is about chemical constituents of ethanol extracts from whole plant of Saussurea laniceps Hand.-Mazz. Fifteen compounds were isolated by column chromatography on normal phase silica gel and Sephadex LH-20. Among them, eleven compounds were isolated from this plant for the first time, and two compounds were isolated from Genus Saussurea for the first time. The second part is about chemical constituents of ethanol extracts from whole plant of Saussurea medusa Maxim. Fifteen compounds were isolated by column chromatography on normal phase, reversed phase silica gel and Sephadex LH-20. Five of them were isolated from this plant for the first time, and there is one new flavonoid glucoside which was identified as 6″-O-crotonoyl-homoplantaginin (M-7) based on the evidence of one- and two-dimensional nuclear magnetic resonance, mass spectrometry analysis, and alkaline hydrolysis reaction. The last part is about chemical constituents of ethanol extracts from whole plant of Saussurea tridactyla Sch.-Bip. ex Hook. f.. Seven compounds were isolated by column chromatography on normal phase silica gel and Sephadex LH-20. There is one compound which was isolated from this plant for the first time. The second chapter consists of three parts. In the first part, we analyzed the chemical constituents of S. tridactyla collected from seven different places in Tibet using HPLC-DAD-ESI-MSn. Fourteen peaks in the HPLC were identified by comparison of UV and MS spectra with those of authentic compounds, among which eight common peaks were quantified. In the second part, we analyzed the chemical constituents of eight Saussurea species using HPLC-DAD-ESI-MSn method. Fifteen peaks in the HPLC were identified by comparison of UV and MS spectra with those of authentic compounds and eight main peaks of them were quantified. In the last part, we analyzed the chemical compounds of the above eight Saussurea plants directly by ESI-MS/MS. Thirteen major compounds, including 10 flavonoids and 3 coumarins were easily rapidly identified. The third chapter consists of three parts. In the first part, we proposed a comparative high quality-control standard for S. laniceps, based on quality detection by TLC and quantity analysis by HPLC using two major compounds (umbelliferone and scopoletin) as standard compounds. In the second part, in viewing S. laniceps, S. tridactyla and S. gossypiphora as the members of one family of medicinal herbs, we suggested a quality-control standard based on the TLC detection of the two major compounds (umbelliferone and scopoletin). In the last part, we proposed a quality-control standard for S. medusa based on the TLC detection of its major component (apigenin 7-O-glucoside). The four chapter analyzed the chemical constituents of essential oil of eight Saussurea species. The essential oils were extracted from the whole plants of these samples with water stream distillation. By GC-MS analysis, we identified eighty-three compounds from S. medusa, eighty-three from S. laniceps, fifty-six from S. quercifolia, thirty-four from S. aster, twenty-one from S. kingii, twenty from S. simpsoniana, twenty-four from S. gossypiphora, and twenty from S. tridactyla respetively, which accounted for 70.7%, 76.0%, 82.2%, 55.4%, 49.7%, 70.4 %, 76.2% and 76.7% of the total essential oil, respectively. The last chapter reviews the research progress of the Genus Saussurea.

几种植物药材的色谱－质谱联用分析

本论文由四章组成，第一、二、三章为实验论文，分别报道了中药羌活、菊花、全缘叶绿绒蒿的化学成分的高效液相色谱(HPLC)和液相色谱-质谱(LC-MS)联用分析以及挥发油的气相色谱-质谱(GC-MS)联用分析。第四章概述了重要藏药材化学成分的研究进展。 第一章首先对28批不同产地的羌活药材进行了HPLC分析，建立了羌活的指纹图谱。结果表明，不同产地羌活的化学成分基本相似，但是各组分在含量上存在较大差异。其次，对羌活的主要化学组分包括紫花前胡苷、紫花前胡素、6'-O-反式阿魏酸紫花前胡苷、茴香酸对羟基苯乙酯、羌活醇和异欧前胡素进行了定量分析。此外，针对同一产地不同采集时间的羌活挥发油进行系统分析，结果表明它们的化学成分基本相似，主要含有a－蒎烯、b－蒎烯、柠檬烯和龙脑乙酸酯等，只是各组分含量有所变化，这说明采集药材时要注意采集时间。 第二章分别报道了不同产地不同品种菊花非挥发性成分的液相色谱－二极管阵列检测－串联质谱(LC-PDA-MSn)分析和挥发性成分的气相色谱－质谱(GC-MS)联用分析比较。首先通过液相色谱－质谱－串联质谱对各色谱峰进行定性分析，通过与标准品对照，以及UV和MSn提供的结构信息，结合文献报道共鉴定了11个化学成分，包括绿原酸和10个黄酮化合物，并比较了不同品种菊花的化学成分相同之处和不同之处。另外，对七种不同品种不同产地的菊花挥发性成分通过GC-MS分析表明其主要挥发性成分为单萜类、倍半萜类化合物，共有成分樟脑、龙脑和龙脑乙酸酯等，各成分在不同挥发油中的含量变化明显。 第三章为藏药全缘叶绿绒蒿不同部位挥发油成分的气相色谱－质谱(GC-MS)联用分析，比较其挥发油化学成分及其含量变化的异同点。研究结果表明，全缘叶绿绒蒿花精油的化学成分明显多于全草部位，且两者主要成分有较大的差别。 第四章综述了青藏高原重要藏药材化学成分的研究进展。分别对藏药的资源特色和110多种常用重要藏药材的化学成分的研究情况以及藏药未来发展思路进行了阐述，以期对相关的研究提供一些信息。 This dissertation consists of four parts. The first part reports studies on the fingerprint of Notopterygium incisum and N. forbesii by HPLC-PDA-MSn, and on the constitutents of essential oil by GC-MS. The second part elaborates the chemical constitutents of Chrysanthemum L. by LC-MS and GC-MS analysis. The third part reports the chemical compositions of the essential oil from the different parts of Meconopsis integrifolia. The fourth part reviews on the progress of the studies on the chemical constitutents in Tibetan medicines. The first chapter is about HPLC analysis of a traditional Chinese herbal medicine Qiang-huo (Notopterygium incisum and N. forbesii ). Firstly, based on analyzing and contrasting the relative retention time and relative paek area in chromatographic fingerprint, the HPLC chromatographic fingerprint of Notopterygium incisum was established, which can used as a scientific basement for the quality evalution of this herb. Secondly, quantitative analysis were performed on the main chemical constitutents of Notopterygium incisum and N. forbesii including nodakenin, nodakenetin, 6’-O-trans-feruloylnodakenin, p-hydroxypenethylanisate, notopterol and isoimperatorin. The results indicated that the contents were variable related to different growth regions. Lastly, the essential oil of Notopterygium incisum collected in different harvest times is analyzed by GC-MS. The second chapter is about HPLC-MS and GC-MS analysis of several species of Chrysanthemum L. Firstly, eleven compounds including chlorogenic acid and ten flavone compounds were identified in the methanol extract of Chrysanthemum morifolium Ramat. from different regions by HPLC-MS analysis. Secondly, the essential oil of seven different species of Chrysanthemum L.were extracted by steam distillation, and its compositions were isolated and identified by GC-MS. The main active constitutents such as camphor, borneol and bornyl acetate were detected, but the relative content varied notably. The third chapter is about GC-MS analysis of the essential oil from different parts of Meconopsis integrifolia. It indicated great difference of the chemical compositions of their oil in the flowers and residual overground part. The last chapter is a review of the research progress of the Tibetan medicines, which includes their features and their main chemical constitutents.

双花千里光、川芎及宽叶羌活的化学成分研究

本论文由四章组成。第一、二和三章分别报道了双花千里光、川芎和宽叶羌活的化学成分研究。从三种药用植物中共分离和鉴定了40 个化学成分，其中8个为新化合物。第四章概述了藳本属植物及日本川芎的化学成分研究进展。 第一章包括三个部分。第一部分报道双花千里光（Senecio dianthus Franch.）地上部分乙醇提取物的化学成分。采用正、反相硅胶柱层析等各种分离方法，从中共分离出8 个艾里莫酚型倍半萜内酯，其中5 个是新化合物，并且有1 个为首次发现的连接了含氮原子取代基的艾里莫酚型倍半萜内酯。它们的结构经MS、IR、NMR及X-单晶衍射等解析方法确定为2b-angeloyloxy-10b-hydroxyeremophil-7(11)-en-8a,12-olide (1)、6b-angeloyloxy-10b-hydroxyeremophil-7(11)-en-8a,12-olide (2)、2b-angeloyloxy-8b,10b- dihydroxyeremophil-7(11)-en-8a,12-olide (3)、2b-angeloyloxy-8a-hydroxyeremophil-7(11),9(10)-dien-8b,12-olide (4)和8b-amino-10b- hydroxyleremophil-7(11)-en-8a,12-olide (5)。这8 个倍半萜内酯经体外生物活性测试表明均具有通过抑制巨噬细胞增殖抵制破骨细胞增生的活性。第二部分对艾里莫酚型倍半萜内酯的质谱裂解规律进行了初步探讨。第三部分报道双花千里光茎、和叶花的挥发油成分分析。采用传统水蒸气蒸馏法分别提取了双花千里光茎、叶和花的挥发油，用气相色谱－质谱联用（GC-MS）技术分别分离鉴定了其化学成分，从茎、叶和花挥发油中各分离和鉴定出70、80 和73 种化学成分，分别占挥发油总量的91.2％、85.7％及93.4％。 第二章包括两个部分。第一部分报道川芎（Ligusticum chuanxiong Hort.）根茎乙醇提取物的化学成分。通过正、反相硅胶柱层析等分离纯化和MS、NMR及X-单晶衍射等解析方法，共分离鉴定了21 个化合物，结构类型分属于苯酞、二聚苯酞、香豆素和脂肪酸类。其中2 个为结构比较新颖的二聚苯酞类化合物：chuanxiongnolide A (19)和chuanxiongnolide B (20)，化合物19 的结构经X-单晶衍射得到确证。第二部分报道川芎挥发油的化学成分。采用不同的提取方法（溶剂萃取法、水蒸气蒸馏法、CO2 超临界流体萃取法）提取川芎挥发油，同时采集不同产地（四川彭县、四川郫县、云南鹤庆）及不同品质（川芎、奶芎、苓子）的川芎产品，利用GC-MS 技术分离鉴定其挥发油的化学成分，计算各成分的相对含量，并对比分析其中的异同。 第三章报道宽叶羌活（Notopterygium forbesii Boiss.）根茎化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR 等解析方法，共分离鉴定了13 个化合物，结构类型分属于香豆素、二氢异香豆素、甾体和羧酸类。其中1 个新二氢异香豆素类成分鉴定为6-methoxy-hydrangenol (37)。 第四章概述了藳本属植物及日本川芎化学成分的研究进展。 This dissertation consisted of four chapters. The former three chaptersrespectively elaborated the phytochemical investigation of three herbal medicines:Senecio dianthus Franch., Ligusticum chuanxiong Hort. and Notopterygium forbesiiBoiss.. Forty compounds, including eight new ones, were isolated and identified byspectral and chemical evidence. The fourth chapter elaborated the study progress ofchemical constituents of Ligusticum genus and Cnidium offcinale. The first chapter consisted of three parts. The first part is about the chemicalconstituents of ethanol extraction and essential oils from the aerial parts of S. dianthu.Eight eremophilenolides were isolated and identified. Among them, five ones are newcompounds and one of them is a novel eremophilenolide attched with an amino group.The structures of the new compounds were identified as 2b-angeloyloxy-10b-hydroxyeremophil-7(11)-en-8a,12-olide (1)，6b-angeloyloxy-10b-hydroxyeremophil-7(11)-en-8a,12-olide (2)，2b-angeloyloxy-8b,10b-dihydroxyeremophil-7(11)-en-8a,12-olide (3)，2b-angeloyloxy-8a-hydroxyeremophil-7(11),9(10)-dien-8b,12-olide (4) and8b-amino-10b-hydroxyeremophil-7(11)-en-8a,12-olide (5) by spectral evidence andX-ray crystallography analysis. All the compounds were evaluated for theiranti-osteoclstogenesis activity using a proliferation inhibit assay with microphagecells. The second part elementarily discussed the characteristic fragmentation oferemophilenolides isolated from S. dianthus in ESI-MS.The latter part is about thechemical constituents of essential oil extracted from stems, leaves and flowers of S.dianthus with steam distillation. By the GC-MS analysis, 70, 80 and 73 compoundswere respectively isolated and identified which accounted for more than 91.2％, 85.7％ and 93.4％ of total essential oil. The second chapter, including two parts, is about the the chemical constituents ofethanol extraction and essential oils from rhizomes of L. chuanxion. In the first part, twenty-one compounds were isolated and iedntified. Two ones are novel dimericphthalides and the structures were suggested as chuanxiongnolide A (19) andchuanxiongnolide B (20) by spectral evidence and confirmed by X-raycrystallography analysis. In the second part, the samples were collected from differentextract techniques (solvent extraction, steam distillation and supercriticalfluid extraction), different habitats (Peng and Pi counties, Sichuan province; Heqing,Yunnan province) and different qualities (Chuanxiong, Naixiong and Lingzi). Thechemical constituents of essential oil from L. chuanxiong were analyzed by GC-MS and were compared each other. The third chapter is about the chemical constituents of rhizomas of N. forbesii,which belongs to a endemic genus of China. Thirteen compounds were isolated andidentified. One of them is a new dihydroisocoumarin and the structure was identifiedas 6-methoxy-hydrangenol (37) by spectral evidence. The fourth chapter is a review on study progress of chemical constituents ofLigusticum species and Cnidium offcinale.

千金子和暖地大叶藓的化学成分研究

本论文由三部分共4 章组成。第一部分阐述了大戟科大戟属传统中药千金子（Euphorbia lathyris L.）化学成分、生物学活性以及千金子化学成分的HPLC、UPLC-MS、GC-MS 分析成果。第二部分介绍了民族药材暖地大叶藓（Rhodobryum giganteum (Schwaegr.) Par.）的化学成分研究和结构鉴定。第三部分概述了大戟属 植物中大环二萜酯的研究进展。 第一章包括1－3 节。在第1, 2 节中报道了千金子（Euphorbia lathyris L.）95% 乙醇提取物的化学成分分离鉴定。我们采用正、反相硅胶柱层析、重结晶等各种分离方法，凭借MS、IR、NMR、X-ray 等现代仪器手段,从中共分离鉴定22 个化合物。其中8 个是高活性化合物前体-续随子烷型大环二萜及3 个巨大戟烷型二萜，还有香豆素、生物碱、甾体等类型，其中完成对5 个大环二萜酯构型的确认，对2 个二萜酯构型进行了修正。第3 节中介绍对千金子化学成分的细胞毒性、α-葡萄糖苷酶抑制活性、P-gp 表达抑制活性的模型筛选结果。 第二章包括3 节，第1 节报道不同产地千金子高效液相色谱定量分析结果。第2 节介绍了各大环二萜酯的HPLC-MS/MS 的分析结果，并且对其质谱裂解规律、UPLC-MS 快速鉴定方法做了进一步讨论。第3 节介绍了千金子挥发油成分分析。采用传统水蒸气蒸馏方法提取千金子中的挥发油，并经气相色谱－质谱联用（GC-MS）技术共分离鉴定出 49 个化合物，占挥发油总量的90.48％。 第三章包括1, 2 两节，第1 节报道了暖地大叶藓化学成分。采用正、反相硅胶，凝胶柱层析等各种分离方法和MS、IR、NMR 等解析手段，共分离鉴定10个化合物，其中一个环肽化合物为新化合物。第2 节介绍了暖地大叶藓挥发油成分分析，共分离鉴定出 52 个化合物，占其挥发油总量的85.67％。 第四章概述了大戟科大戟属植物中大环二萜酯的研究进展。 This dissertation consists of three parts. In the first part, it is elaborated that the phytochemical investigation from the traditional Chinese medicine: seeds of Euphorbia lathyris L.. Biological activity and constituents analysis by HPLC、UPLC-MS、GC-MS were reported. In the second part, it is discussed that the chemical constituents were isolated and identificated from minority nationalitical herb－Rhodobryum giganteum (Schwaegr.) Par.. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia. The first part is composed of 1－3 sections. The section 1and 2 is focused on the isolation and identification of chemical constituents from seeds of E. lathyris. 22 compounds were isolated from the seeds of E. lathyris. by isolation methods of column chromatography (silica gel, including reversed phase) and recrystallisation on the basis of spectroscopic methods including IR, MS, NMR and X-ray. In 8 macrocyclic and 3 ingenane diterpenes, the relative configuration of 5 macrocyclic diterpenes were confirmed, in which 2 were amended. In the third section, cell cytotoxic activity, restraining activity of α-Glucosidase and multidrug resistance (MDR) reversing activity about P-gp were tested. 5 potential revsering reagents were found. The second part is composed of 1－3 sections. In first section it is described that the quality of the chemical constituents of E. lathyris from 5 sources , which were analyzed by high-performance liquid chromatography. In addition, the fractionation rules of some macrocyclic diterpenes were discussed and Ultra Performance Liquid Chromatography/ electrospray ionization mass spectrometry (UPLC-MS) was applied for quick determination of compounds in the second section. In the third section, chemical analysis of the essential oil from seeds of E. lathyris by GC-MS were reported. The essential oil from the seeds of E. lathyris L. in Sichuan was extracted by steam distillation and 49 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 90.46% of the total essential oil. The second part, including section 4 and 5, is about the phytochemical investigation of R. giganteum. In the former section, ten compounds were isolated and identified. Among them, a new peptide was characterized by spectroscopic analysis including IR, MS and NMR. In the other section, 52 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 85.67% of the total essential oil. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia.

Factors affecting pore structure and performance of poly(vinylidene fluoride-co-hexafluoro propylene) asymmetric porous membrane

Preparation of poly(vinylidene fluoride-co-hexafluoro propylene) (F2.6) flat-sheet asymmetric porous membrane has been studied for the first time. Factors affecting F2.6 membrane pore structure and permeate performance, such as macromolecule pore formers (polyethylene glycol-400, 1000, 1540, 2000 and 6000), the small molecule former (glycerol), swelling agent (trimethyl phosphate) in casting solution, precipitating bath component and temperature, exposure time and ambient humidity, were investigated in detail. Average pore radius and porosity were used to characterize F2.6 membrane structure, and respectively, determined by ultrafiltration and gravimetric method for the wet membrane. Morphology of the resultant membranes was observed by scanning electronic microscopy (SEM). Final test on permeate performance of F2.6 porous membrane was carried out by a direct contact membrane distillation (DCMD) setup. The experimental F2.6 membrane exhibits a higher distilled flux than PVDF membrane under the same operational situations. The determination of contact angle to distilled water also reveals higher hydrophobic nature than that of PVDF membrane.

Analysis of chemical constituents of essential oil in purple magnolia leaves by gas chromatography-mass spectrometry

The essential oil in purple magnolia leaves was extracted by steam distillation approaches. The oil obtained was dried with anhydrous magnesium sulfate. According to the analysis of gas chromatography/mass spectrometry, more than 40 peaks were separated and 32 compounds were identified. The identified constituents represent 95% of the peak area of the essential oil. The main compounds were germacrene-D, santolina triene, caryophyllene, 1,3,7-octatriene, 3,7-dimethyl, and camphene, etc.

Heterogenization of heteropolyacids: A general discussion on the preparation of supported acid catalysts

Heteropolyacids (HPAs) possess both acidic and redox catalytic properties and held extensive promise of practical application. These type of compound display a great potential of specific synthesis reactions for replacing sulfuric acid to satisfy the requirements of environmental protection. Heterogenizing HPAs would not only make them more useful in liquid phase oxidation with oxygen and in acid-catalyzed reaction, as the catalyst is often difficult to separate from the reaction products, but also create favorable factors for realizing heterogenization of homogeneous reaction and even utilizing new technology of catalytic distillation. In this paper, different kinds of porous materials which are well characterized, including oxides such as Al2O3, SiO2, TiO2, diatomite, bentonite, and active carbon of different sources, were used as support for heterogenizing HPAs (in different media), and the obtained results, the intrinsic characters of supports which may influence both the nature of the interaction between HPAs and supports in the heterogenization and the activity in the catalytic reaction, are explored. It is expected that these can provide a referential model for preparing supported acid catalyst used in liquid phase.

Pretreatment Method for Nitrogen Isotopic Analysis of Nitrate in Seawater

A suitable method for the pretreutment of dissolved nitrate samples in seawaters for nitrogen isotopic analysis was established. First, the seawater samples were processed by removing nitrite and amonium. Then Devard's alloy was added in sample for conversion of dissolved nitrate to ammonium. The sample was distilled, and then the ammonium condensate was collected with zeolite. after distillation, the collected condensate was filtered and prepared for determining nitropic values. Some tests of the method were conducted. The distillation condition, the influence of salinity on nitrogen isotopic analysis, absorption of ammonium onto zeolite and an improved method on a large volume of seawater were discussed in this study. The results showed that the distillation step had an average recovery of (104.9 +/- 4.2) % (n = 6) when distillating every 300 mL aliquot of the sample under a strong alkaline condition with 0.5 g devard's alloy and a distillation time of 30 min. The nitrogen isotopic fractionation decreased markedly when salinity was increased from 0% to 0.5%; further increase(1% - 3.5%) showed little effect. The adsorption rate of ammonium onto zeolite had a high yield of (95.96 +/- 1.08) % (n = 6) in average. An improved collection method was used to process a large volume of seawater with several distillations, and had good effect on analysis. The method had been applied to analyze water samples collected from Changjiang estuary. The analytical results indicate that the method is suitable for delta N-15 analysis of dissolved nitrate in seawaters. The present method could provide valuable information about the source and cycle mechanism of dissolved nitrogen in estuary waters.

Nitrogen isotope fractionation during nitrate, ammonium and urea uptake by marine diatoms and coccolithophores under various conditions of N availability

Stable isotopes of N provide a new approach to the study of algal production in the ocean, yet knowledge of the isotope fractionation (epsilon) in various oceanic regimes is lacking. Here we report large and rapid changes in isotope composition (delta(15)N) of 2 coastal diatoms and 2 clones (open and coastal) of a coccolithophore grown in the simultaneous presence of nitrate, ammonium and urea under varying conditions of N availability (i.e. N-sufficiency and N-starvation followed by N-resupply) and hence different physiological states, During N-sufficiency, the delta(15)N of particulate organic N (PON) was well reproduced, using a model derived from Rayleigh distillation theory, with constant epsilon similar to that for growth on each individual N source. However, following N-resupply, the variations in delta(15)N(PON) could be well explained only in the case of the open ocean Emiliania huxleyi, with epsilon similar to N-sufficient conditions. It was concluded that the mechanism of isotope fractionation changed rapidly with N availability for the 3 coastal clones. However, in the case of E. huxleyi isolated from the Subarctic Pacific Ocean, no evidence of a change in mechanism was found, suggesting that perhaps open ocean species can quickly recover from N-depleted conditions.