路易斯酸催化莰烯异构酯化合成乙酸异龙脑酯的研究

以路易斯酸为催化剂催化莰烯与冰乙酸酯化制备乙酸异龙脑酯,通过催化剂筛选和反应条件的优化,获得了莰烯与冰乙酸酯化反应合成乙酸异龙脑酯的最佳反应条件,即:FeCl_3为催化剂,添加量为莰烯质量的10%,反应温度在25℃,反应时间2h,n(莰烯)∶n(冰乙酸)1∶3。在此条件下,采用含莰量94.9%的莰烯(莰烯84.8%,三环烯10.1%)为原料进行反应时,莰烯转化率接近99%,乙酸异龙脑酯选择性94%,乙酸异龙脑酯的平均产率88%。     

八面沸石在精细有机合成中催化作用研究（Ⅵ）──DUSY上莰烯与乙酸酯化反应研究

报道了ＤＵＳＹ催化莰烯与乙酸直接酯化反应。考察了催化剂用量、乙酸用量、反应温度及反应时间对该反应的影响。研究结果表明，在ＤＵＳＹ催化剂上，于８０℃条件下反应８ｈ，工业莰烯的转化率达８５．７％。其主要产物为乙酸异龙脑酯，乙酸异葑酯，异龙脑等。其中生成乙酸异龙脑酯的选择性为９４．１％。     

微波辐射下莰烯与羧酸加成反应的研究

研究了微波辐射下莰烯与羧酸用对甲苯磺酸作催化剂在密闭反应罐中的加成反应,系统探讨了在微波辐射下各因素对莰烯与羧酸(主要是甲酸)加成反应的影响.研究结果表明,在莰烯、甲酸和对甲苯磺酸分别为25、53和0.20 mmol时,于700 W功率的微波辐射下,莰烯与甲酸反应40 s,反应液中甲酸异龙脑酯的含量可达77.2 %,微波辐射大幅度地提高了莰烯与甲酸的加成反应速率,缩短了反应时间,为工业上莰烯的酯化工艺改进提供了新的思路.     

微波辐射下莰烯与羧酸加成反应的研究

研究了微波辐射下莰烯与羧酸用对甲苯磺酸作催化剂在密闭反应罐中的加成反应，系统探讨了在微波辐射下各因素对莰烯与羧酸(主要是甲酸)加成反应的影响。研究结果表明，在莰烯、甲酸和对甲苯磺酸分别为25、53和0．20mmol时，于700W功率的微波辐射下，莰烯与甲酸反应40s，反应液中甲酸异龙脑酯的含量可达77．2％，微波辐射大幅度地提高了莰烯与甲酸的加成反应速率，缩短了反应时间，为工业上莰烯的酯化工艺改进提供了新的思路。     

-蒎烯经二溴莰烷合成冰片二烯

以α-蒎烯为原料与Br2进行加成、异构化反应合成2,6-二溴莰烷,以2,6-二溴莰烷为中间体制备冰片二烯。α-蒎烯合成2,6-二溴莰烷的条件:Br2和α-蒎烯为2.5∶1(物质的量之比),反应温度为0℃,反应时间24 h,反应溶剂为二氯甲烷,此条件下α-蒎烯转化率为97.6%,定向转化为2,6-二溴莰烷的选择性最高(48.8%)。提纯后的2,6-二溴莰烷纯度为99.0%,得率为45.6%。以提纯后的2,6-二溴莰烷为原料制备冰片二烯的适宜反应条件:反应温度100℃,反应时间5 h,叔丁醇钾为消除试剂,叔丁醇钾与2,6-二溴莰烷投料比4∶1(物质的量比),DMF为溶剂。2,6-二溴莰烷转化率为99.12%,冰片二烯的选择性为99.0%,提纯后的冰片二烯纯度可达98.5%。采用FT-IR、GC-MS和1H NMR等方法对2,6-二溴莰烷和冰片二烯进行了结构鉴定。     

3'-(3,3-二甲基双环[2.2.1]庚-2-亚基)-5'-苯基-异噁唑啉的合成与表征

以2-(3,3-二甲基双环[2.2.1]庚-2-亚基)乙醛肟(莰烯醛肟)和苯乙烯为原料,通过环加成反应合成了未见报道的3'-(3,3-二甲基双环[2.2.1]庚-2-亚基)-5'-苯基-异噁唑啉,并采用FT-IR、GC-MS、~1H NMR以及~(13)C NMR等手段对产物进行表征,确定了产物结构。探讨了溶剂种类、催化剂种类及用量、氧化剂过硫酸氢钾复合盐(Oxone)用量、苯乙烯用量以及反应时间对反应转化率和得率的影响,得到适宜的工艺条件为:50%甲醇为溶剂,氯化钾为催化剂,n(莰烯醛肟)∶n(氯化钾)∶n(Oxone)∶n(苯乙烯)=1.0∶0.5∶1.5∶2.0,反应时间10 h,在此条件下,产物得率为88.07%。     

Synthesis of the Bomadiene from 2,6-Dibromocamphane

以α-蒎烯为原料与Br2进行加成、异构化反应合成2,6-二溴莰烷,以2,6-二溴莰烷为中间体制备冰片二烯.α-蒎烯合成2,6-二溴莰烷的条件:Br2和α-蒎烯为2.5∶1(物质的量之比),反应温度为0℃,反应时间24h,反应溶剂为二氯甲烷,此条件下α-蒎烯转化率为97.6％,定向转化为2,6-二溴莰烷的选择性最高(48.8％).提纯后的2,6-二溴莰烷纯度为99.0％,得率为45.6％.以提纯后的2,6-二溴莰烷为原料制备冰片二烯的适宜反应条件:反应温度100℃,反应时间5h,叔丁醇钾为消除试剂,叔丁醇钾与2,6-二溴莰烷投料比4∶1(物质的量比),DMF为溶剂.2,6-二溴莰烷转化率为99.12％,冰片二烯的选择性为99.0％,提纯后的冰片二烯纯度可达98.5％.采用FT-IR、GC-MS和1H NMR等方法对2,6-二溴莰烷和冰片二烯进行了结构鉴定.     

冰片烯的合成研究

分别以α-蒎烯、β-蒎烯和莰烯为原料,合成2-氯莰烷,再以2-氯莰烷为原料合成冰片烯. α -蒎烯合成2-氯莰烷的反应温度为-5℃, β -蒎烯合成2-氯莰烷的反应温度为-10℃;莰烯合成2-氯莰烷的反应条件是以氯化锌为催化剂、投料比6∶1(物质的量比,下同)、温度为35℃,反应时间24h.2-氯莰烷合成冰片烯的工艺条件为,以叔丁醇钾为消除反应试剂、投料比为3∶1、DMF为溶剂、反应温度为120℃、反应时间为3h.采用FT-IR、GC-MS和1HNMR等方法对2-氯莰烷和冰片烯进行了结构鉴定.     

脱氢枞酸基甲基丙烯酸酯单体的合成和表征

以脱氢枞酸(DA)和甲基丙烯酸缩水甘油酯(GMA)为原料,通过酯化反应合成了脱氢枞酸(2-甲基丙烯酰氧基异丙醇基)酯(DAGMA),探讨了反应时间、反应温度、催化剂种类及催化剂用量对合成DAGMA的影响,对DAGMA的结构和性能分别采用FT-IR、~1H NMR、~(13)C NMR、DSC、和GPC进行表征。研究结果表明:DAGMA较适合的合成条件为n(AD)∶n(GMA)1∶1,以三乙胺作催化剂,用量为脱氢枞酸质量的2%,反应时间5 h,反应温度120℃,酯化率约为85%。DSC分析显示,在引发剂AIBN存在下,DAGMA可发生聚合反应,得到均聚物的重均相对分子质量(M_w)23 900,数均相对分质量(M_n)12 254,玻璃化转变温度(T_g)为62.61℃。     

-蒎烯合成龙脑研究

在固体超强酸催化作用下β-蒎烯和无水草酸平稳地发生酯化反应,生成草酸龙脑酯;加入氢氧化钠溶液发生皂化反应得到龙脑。酯化反应采用程序升温的方式（65℃、1h,75℃、4h,90℃、1h）,皂化反应时间为1h。在上述反应条件下,当催化剂SO4^2-／ZrO2用量为7％时（以β-蒎烯质量计,下同）,粗龙脑产率为62．0％,产品中正、异龙脑比为13．6：48．7;当催化剂S2O8^2-／ZrO2用量为7％时,粗龙脑产率为66．7％,正、异龙脑比为11．5：49．5;这两种催化剂对正龙脑选择性比较差。当用稀土复合固体超强酸SO4^2-／ZrO2-CeO2为催化剂,用量3％时,粗龙脑产率为56．1％,但对正龙脑的选择性高于其他催化剂,正、异龙脑比为46．0：23．2。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.