Selection of thermal,spectroscopic, spectrometric,and chromatographic methods for characterizing historical celluloid

Celluloid in museum collections is very unstable; therefore, heritage professionals carry out research studies dedicated to understanding its decay and prolonging its lifetime. This paper addresses the need to compare and select suitable analytical methods for that purpose. Thermogravimetric analysis coupled with Fourier transform infrared spectroscopy, evolved gas analysis–mass spectrometry, double shot – gas chromatography/mass spectrometry, and gel permeation chromatography (GPC) were employed to characterize the emission of gasses (decay products) and measure the molecular weight and camphor (plasticizer) content from unaged, artificially, and naturally aged celluloid samples. A pioneer GPC set-up for the quantification of camphor was introduced for the first time in this study. Results demonstrated that GPC was the most suitable method for assessing material changes due to degradation. Both set-ups, for measuring molecular weight and quantifying camphor, appear promising for assessing the effect of conservation treatments and investigating the heterogeneous degradation of celluloid objects in future studies.     

Simple Plug-In Synthetic Step for the Synthesis of (−)-Camphor from Renewable Starting Materials

Racemic camphor and isoborneol are readily available as industrial side products, whereas (1R)-camphor is available from natural sources. Optically pure (1S)-camphor, however, is much more difficult to obtain. The synthesis of racemic camphor from α-pinene proceeds via an intermediary racemic isobornyl ester, which is then hydrolyzed and oxidized to give camphor. We reasoned that enantioselective hydrolysis of isobornyl esters would give facile access to optically pure isoborneol and camphor isomers, respectively. While screening of a set of commercial lipases and esterases in the kinetic resolution of racemic monoterpenols did not lead to the identification of any enantioselective enzymes, the cephalosporin Esterase B from Burkholderia gladioli (EstB) and Esterase C (EstC) from Rhodococcus rhodochrous showed outstanding enantioselectivity (E>100) towards the butyryl esters of isoborneol, borneol and fenchol. The enantioselectivity was higher with increasing chain length of the acyl moiety of the substrate. The kinetic resolution of isobornyl butyrate can be easily integrated into the production of camphor from α-pinene and thus allows the facile synthesis of optically pure monoterpenols from a renewable side-product.     

HPLC法快速测量市售卫生球中萘的含量

萘是一种潜在的致癌物.市售卫生球中萘含量的测定受到关注.多采用气相色谱法测定卫生球中的萘含量.探讨了HPLC法用于测定卫生球中萘的含量的方法.以甲醇为流动相,用纯萘为标准物质,建立了HPLC法测量萘含量的标准曲线,用HPLC法测定了在市场上随机购买的5种樟脑丸中萘的含量.结果表明,萘的含量都较高.     

Identification of Camphor Oxidation and Reduction Products in <Emphasis Type="Italic">Pseudomonas putida</Emphasis>: New Activity of the Cytochrome P450<Subscript>cam</Subscript> System

P450 enzymes are known for catalyzing hydroxylation reactions of non-activated C-H bonds. For example, P450_cam from Pseudomonas putida oxidizes (1R)-(+)-camphor to 5-exo-hydroxy camphor and further to 5-ketocamphor. This hydroxylation reaction proceeds via a catalytic cycle in which the reduction of dioxygen (O₂) is coupled to the oxidation of the substrate. We have observed that under conditions of low oxygen, P. putida and isolated P450_cam reduce camphor to borneol. We characterized the formation of borneol under conditions of low oxygen or when the catalytic cycle is shunted by artificial oxidants like m-chloro perbenzoic acid, cumene hydroperoxide, etc. We also tested the toxicity of camphor and borneol with P. putida and Escherichia coli. We have found that in P. putida borneol is less toxic than camphor, whereas in E. coli borneol is more toxic than camphor. We discuss a potental ecological advantage of the camphor reduction reaction for P. putida.     

樟树籽核油的开发与利用研究

介绍了樟树籽的植物学组成及用途 ,研究了樟树籽核油的加工方法 ,得出环己烷是提取核油较好的溶剂 ,分析了油脂的理化常数及化学组成 ,提出樟树籽的综合利用新途径。     

三水磷酸钾耦合CaO对樟木粉热解特性及NOx前体释放特性的影响

利用生物质催化热解生产高附加值化学品具有广阔的应用前景,但热解过程中排放的NO_x会对环境造成不利影响。本文利用热重-质谱联用技术（TG-MS）探究樟木粉热解特性及热解过程中主要NO_x前体的释放特性,对比分析CaO耦合磷酸盐对樟木粉热解过程中NO_x前体生成的反应过程的影响。实验结果显示,随着三水磷酸钾和CaO的加入,樟木粉热解过程中挥发性产物的释放量有所增加而固相产物的产率有所减少;同时,混合热解过程中生成的主要NO_x前体的离子流强度曲线有所降低。这表明,三水磷酸钾和CaO的耦合作用,一方面能够改善樟木粉的热解特性,使热解过程更加彻底;另一方面能够有效抑制樟木粉中含氮化合物的一次裂解,延缓NH₃等NO_x前体的生成、减少HCN等NO_x前体的释放。     

浸取/气相色谱法表征发射药中钝感剂的浓度分布

采用丙酮石油醚混合溶剂为浸取液浸泡发射药,用气相色谱测定不同时刻从发射药中浸取出来的樟脑,用浸取液中的樟脑浓度c与浸取时间t的关系曲线表征发射药中的樟脑浓度分布。重复实验结果表明,对同一发射药样品。在确定的浸取条件下,浸取曲线重复性一致,浸取曲线仅由发射药中樟脑的浓度分布来确定。实验结果表明,当樟脑的浓度分布变化时,浸取曲线也发生相应变化。因此,可以用浸取／气相色谱法来表征发射药中钝感剂樟脑的浓度分布。     

《日用樟脑》行业标准的研制及应用

根据市场需求研究制定了林业行业标准《日用樟脑》。该标准主要规定了日用樟脑的外观、性状、嗅味感、要求、试验方法、功能添加剂、形状、大小、包装、标识、贮存、运输、卫生和管理,适用于以合成樟脑或者天然樟脑为基本原料制得的各种不同形状的日用樟脑制品。研究建立了以气相色谱分析为主的相应检测和分析试验方法,确定了含量、密度等主要技术参数及取值范围。同时还研究了日用樟脑中相关掺假制假物质的分析检验方法。     

CHEMOTYPIC Variation in Volatiles and Herbivory for Sagebrush

Plants that are damaged by herbivores emit complex blends of volatile compounds that often cause neighboring branches to induce resistance. Experimentally clipped sagebrush foliage emits volatiles that neighboring individuals recognize and respond to. These volatiles vary among individuals within a population. Two distinct types are most common with either thujone or camphor as the predominate compound, along with other less common types. Individuals respond more effectively to cues from the same type, suggesting that some of the informative message is contained in the compounds that differentiate the types. In this study, we characterized the chemical profiles of the two common types, and we examined differences in their microhabitats, morphologies, and incidence of attack by herbivores and pathogens. Analysis by gas chromatography coupled with mass spectrometry revealed that the camphor type had higher emissions of camphor, camphene, and tricyclene, while the thujone type emitted more α-thujone, β-thujone, (Z)-salvene, (E)-salvene, carvacrol, and various derivatives of sabinene. We were unable to detect any consistent morphological or microhabitat differences associated with the common types. However, plants of the thujone type had consistently higher rates of damage by chewing herbivores. One galling midge species was more common on thujone plants, while a second midge species was more likely to gall plants of the camphor type. The diversity of preferences of attackers may help to maintain the variation in volatile profiles. These chemical compounds that differentiate the types are likely to be informative cues and deserve further attention.     

π-氧化樟脑的合成

以(+)-樟脑为原料,先经二次溴化、还原得(+)-π-溴代樟脑,再经酯化、水解和氧化反应合成了强心药物π-氧化樟脑。确定了较佳工艺条件:(1)溴化反应:n〔(+)-樟脑〕∶n(Br2)=1∶1.4,冰醋酸为溶剂,80℃下反应6h,(+)-α-溴代樟脑收率88.5%;n〔(+)-α-溴代樟脑〕∶n(Br2)=1∶1.1,氯磺酸为助剂,室温下反应2 h,(+)-α,π-二溴代樟脑收率80.1%。(2)还原反应:n〔(+)-α,π-二溴代樟脑〕∶n(Zn)=1∶3,冰醋酸为溶剂,冰浴反应3h,(+)-π-溴代樟脑收率66.3%。(3)酯化-水解反应:n〔(+)-π-溴代樟脑〕∶n(CH3COOK)=1∶1.5,冰醋酸为溶剂,190℃下反应30 h,除去溶剂后用V(CH3CH2OH)∶V〔w(KOH)=55%的水溶液〕=1∶9的水解液,回流反应2.5 h,(+)-π-羟基樟脑收率78.1%。(4)氧化反应:选用氯铬酸吡啶嗡盐(PCC)作氧化剂,n(PCC)∶n〔(+)-π-羟基樟脑〕=2∶1,CH2Cl2作溶剂,氮气保护下室温反应2 h,π-氧化樟脑收率95.5%。目标产物总收率35%。中间体及目标产物结构经IR、GC-MS和1HNMR确证。     

合成樟脑行业发展现状分析

详细研究了合成樟脑行业的发展现状,探讨了促进和影响行业发展的主要因素。国内外合成樟脑的生产能力为3.235 万t,但正常生产的企业仅9家。2008年全球合成樟脑产量约2.365 万t,其中国内生产量约1.63 万t,印度的产量0.735 万t。2008年中国出口量0.81 万t,出口价格3546 USD/t,出口到70余个国家和地区,其中印度、泰国、德国、美国、日本居前5位,近6年几乎没有变化。消费量相近且最大的国家为印度和中国。合成樟脑的生产主要有2种工艺方法,以传统的酯化-皂化法和一步水合法合成中间体异龙脑为区别,传统工艺方法仍是主流。质量控制标准体系中有工业品国家标准、民用品行业标准和药用产品的药典标准,以及为标准服务用的标准样品。已经有环境标志产品等相关法律、法规、政策和文件为合成樟脑行业的发展提供了良好的支撑和保障,而民用品市场的发展依然有赖于大众生活水平和健康认识水平的进一步提高以及国家政策的引导。     

Camphor from juvenile white spruce as an antifeedant for snowshoe hares

One theory in plant antiherbivore defense predicts that slow growing late succession plants like white spruce (Picea glauca) make large investments in antiherbivore defenses. Juvenile stages of white spruce in the Yukon, Canada, are rarely browsed by snowshoe hares (Lepus americanus), an abundant herbivore, but mature spruce is a highly preferred food. The hexane-soluble fractions of the methanol extracts from juvenile and mature white spruce contain camphor and bomyl acetate. There is four times as much camphor in juvenile spruce as in mature spruce from GC analysis. Plant extracts were added to rabbit chow. Pairs of extracts were offered to hares in choice tests. These tests demonstrated that camphor in the juvenile spruce extracts deterred feeding. Bornyl acetate did not have a clear antifeeding effect.On leave from the Department of Chemistry, University of South Pacific, Fiji.     

Organic‐acid‐catalyzed sol–gel route for preparing poly(methyl methacrylate)–silica hybrid materials

In this study, a series of organic–inorganic hybrid sol–gel materials consisting of a poly(methyl methacrylate) (PMMA) matrix and dispersed silica (SiO₂) particles were successfully prepared through an organic‐acid‐catalyzed sol–gel route with N‐methyl‐2‐pyrrolidone as the mixing solvent. The as‐synthesized PMMA–SiO₂ nanocomposites were subsequently characterized with Fourier transform infrared spectroscopy and transmission electron microscopy. The solid phase of organic camphor sulfonic acid was employed to catalyze the hydrolysis and condensation (i.e., sol–gel reactions) of tetraethyl orthosilicate in the PMMA matrix. The formation of the hybrid membranes was beneficial for the physical properties at low SiO₂ loadings, especially for enhanced mechanical strength and gas barrier properties, in comparison with the neat PMMA. The effects of material composition on the thermal stability, thermal conductivity, mechanical strength, molecular permeability, optical clarity, and surface morphology of the as‐prepared hybrid PMMA–SiO₂ nanocomposites in the form of membranes were investigated with thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, gas permeability analysis, ultraviolet–visible transmission spectroscopy, and atomic force microscopy, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

发射药中钝感剂含量与分布的测定

利用气相色谱法对某新型发射药中钝感剂含量与分布进行了测定。借助一些假设和萃取时间及所萃取樟脑含量数据,建立了钝感剂在发射药中的含量分布模型。分析了结果误差,计算了含樟脑发射药的内弹道性能。讨论了钝感剂含量及其分布对内弹道性能主要指标pm,v0的影响。结果表明,所提出的基本假设是合理的,钝感剂含量及分布显著影响内弹道性能。     

樟树资源化学加工利用产业发展现状

油樟和樟树化学型中的芳樟、龙脑樟是中国特色樟科树种,总面积约8万公顷,主要分布在四川宜宾、四川广安、江西赣州、广西南宁、湖南新晃等地.樟树叶油中的1,8-桉叶素、芳樟醇和天然龙脑是重要的出口产品,也是医药、香精香料和日化行业的主要原料.本文综述了樟树资源特征、分布,介绍了油樟油、芳樟油、龙脑樟油的化学组成和生物活性,樟...     

Photocurable ceramic slurry using solid camphor as novel diluent for conventional digital light processing (DLP) process

This study presents the utility of solid camphor as a novel type of diluent for the preparation of photocurable ceramic slurries with sufficiently low viscosity at high solid loading (48 vol%), which can be applicable for the conventional digital light processing (DLP) process. The camphor addition remarkably decreased the viscosity of calcium phosphate (CaP) ceramic slurries without affecting their photopolymerization behavior. This approach could effectively mitigate the clogging of pores with residual slurries, and thus the porous structure of porous CaP scaffolds with 3D channels could be tightly controlled. Furthermore, the high densification of CaP frameworks after sintering at 1250 °C for 3 h could be achieved owing to the use of the high solid loading in the CaP slurry. The porous CaP scaffolds produced displayed high compressive strength (˜ 23.8 MPa) and modulus (˜ 276 MPa) at a high porosity of ˜ 50.6 vol%.     

Synthese und Reaktionen von β-Campholenverbindungen

Synthesis and Reactions of β-Campholene Compounds In contrast to the well known α-campholenic ( B ) and fencholenic compounds ( C ) little is known about β-campholenic derivatives ( A ) because of their difficult accessibilitiy. β-Campholenic compounds ( A ) can be obtained: (1) by Baeyer-Villiger oxidation of camphor via lactone 7 and β-dihydrocampholenic lactone ( 5 ); (2) by Beckmann fragmentation of camphor oxime via α-( 2 ) and β-campholenic nitril ( 3 ) and the lactone 5 ; and ( 3 ) by acid catalysed rearrangement of α-campholenic derivatives ( B , 17a , b ). The β-analogous brahmanol ( 14 ) can be synthesized by the reaction of the β-campholenic bromide ( 11 ) with methyl diethyl malonate or by rearrangement of brahmanol.     

Binary gas diffusivity estimates from transient,one-dimensional sublimation–diffusion experiments in a spherical enclosure

Binary gas diffusivities D_AB’s are extremely useful in the analysis/design of mass transfer systems and to develop correlations. This study used an unsteady experimental method to determine D_AB’s in gas pairs starting with a sublimating solid (A) such as naphthalene or camphor and air (B). The cumulative fractional mass transferred from the surface of a solid A sphere placed concentrically within an isothermal spherical enclosure was followed gravimetrically with time. The experimental D_AB,exp for the gas pair was determined by nonlinear regression using the solution to a transient, one-dimensional (radial) diffusion model. The model’s Case 1 option assumed impermeability (no flux of gas A) at the enclosure’s outer surface, while Case 2 assumed zero concentration of gas A at the same location. For naphthalene–air, D_AB,exp overestimated the literature values, the errors ranging from ?110 to ?185% for Case 1 and ?21 to ?65% for Case 2. For camphor–air, the error in D_AB,exp was ?36% for Case 1 and ?16% for Case 2. D_AB,exp for camphor in atmospheric air is herein reported for the first time. Potential improvements to the experiments include automation of the sphere melt-casting process and tighter control of the enclosure’s environmental conditions. Likewise, the theoretical model could be extended to three dimensions with multicomponent diffusion to assess the effect of air humidity on the transport of gas A. This is the first attempt to determine D_AB,exp for naphthalene–air and camphor–air from an unsteady sublimation–diffusion experiment and to model the results using rigorous mass transport theory.     

Adsorption of camphor and 2,2′-bipyridine on Bi(1 1 1) electrode surface

Impedance spectroscopy and in situ STM methods have been used for investigation of the camphor and 2,2′-bipyridine (2,2′-BP) adsorption at the electrochemically polished Bi(1 1 1) electrode from weakly acidified Na₂SO₄ supporting electrolyte solution. The influence of electrode potential on the adsorption kinetics of camphor and 2,2′-BP on Bi(1 1 1) has been demonstrated. In the region of maximal adsorption, i.e. capacitance pit in the differential capacitance versus electrode potential curve, the heterogeneous adsorption and diffusion steps are the rate determining stages for camphor and 2,2′-BP adsorption at the Bi(1 1 1) electrode. It was found that for camphor | Bi(1 1 1) interface the stable adsorbate adlayer detectable by using the in situ STM method has been observed only at the positively charged electrode surface, where the weak co-adsorption of SO₄²⁻ anions and camphor molecules is possible. At the weakly negatively charged Bi(1 1 1) electrode surface there are only physically adsorbed camphor molecules forming the compact adsorption layer. The in situ STM data in a good agreement with impedance data indicate that a very well detectable 2,2′-BP adsorption layer is formed at Bi(1 1 1) electrode in the wide region of charge densities around the zero charge potential.     

手性助剂樟脑磺酸酯的合成工艺研究

以樟脑磺酸为起始原料,通过两步反应,合成了樟脑磺酸酯,并用IR和1 H NMR进行了表征。优化条件为:n(樟脑磺酰氯)∶n(甲醇)∶n(吡啶)=1.0∶2.5∶4.0,在-5℃下反应2h,樟脑磺酸甲酯的收率达到了73.2%,产品质量分数为99.6%。