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1.
制备、表征了酸功能化离子液体1-(3-磺酸)丙基-3-甲基咪唑磷酸二氢盐((HSO3-pmim)H2PO4),并用于催化合成乙酸松油酯的反应研究,考察了反应时间、反应温度、原料配比、催化剂用量等因素对反应的影响.在松油醇5.1 g、n(松油醇):n(乙酸酐)1:1.5、离子液体1.5 g、反应温度40 ℃、反应时间8 h的工艺条件下,松油醇转化率为100 %,乙酸松油酯的选择性为87.2%;并对离子液体(HSO3-pmim)H2PO4的重复使用性能进行了考察,离子液体在不经处理直接重复使用6次后,松油醇的转化率为99.4%,乙酸松油酯的选择性为88.6%,具有较好的重复使用性能.  相似文献   

2.
制备、表征了酸功能化离子液体1-(3-磺酸)丙基-3-甲基咪唑磷酸二氢盐((HSO,-pmim)H2PO4),并用于催化合成乙酸松油酯的反应研究,考察了反应时间、反应温度、原料配比、催化荆用量等因素对反应的影响。在松油醇5.1g、n(松油醇):n(乙酸酐)1:1.5、离子液体1.5g、反应温度40℃、反应时间8h的工艺条件下,松油醇转化率为100%,乙酸松油酯的选择性为87.2%;并对离子液体(HSO3-pmim)H2PO4的重复使用性能进行了考察,离子液体在不经处理直接重复使用6次后,松油醇的转化率为99.4%,乙酸松油酯的选择性为88.6%,具有较好的重复使用性能。  相似文献   

3.
磷酸/离子液体复合体系催化合成乙酸松油酯的研究   总被引:7,自引:2,他引:5  
将3种磷酸与离子液体组成的复合体系用于催化合成乙酸松油酯的反应,其中,H3PO4/[C4m im]BF4和H3PO4/[C8m im]BF4均显示出很高的催化活性;以H3PO4/[C4m im]BF4为代表,详细考察了反应的影响因素;得出最佳工艺条件:n(松油醇)∶n(乙酸酐)为1∶1.5,松油醇0.03 mol,磷酸0.03 g,反应温度40℃,反应时间10 h,离子液体[C4m im]BF45 g,此条件下所得粗产物中未反应松油醇质量分数仅为0.9%,松油醇的质量分数86.5%,松油烯11.0%。H3PO4/[C4m im]BF4复合体系重复使用7次后,适当补加H3PO4可使催化活性与新催化体系相当。  相似文献   

4.
以乳酸和薄荷醇为原料,以合成的离子液体[Hnmp]+HSO4-为催化剂,合成乳酸薄荷酯,并与H2SO4、钨硅酸2种催化剂进行比较.结果明表:离子液体[Hnmp]+HSO4-的催化和重复使用效能均优于催化剂H2SO4、钨硅酸;离子液体[Hnmp]+HSO4-催化合成乳酸薄荷酯的最佳反应条件为n(薄荷醇)∶n(乳酸)=1....  相似文献   

5.
制备、表征了酸功能化离子液体1-(3-磺酸)丙基-3-甲基咪唑对甲苯磺酸盐((HSO3-pmim)pTSA),并用于催化合成松香甲酯的反应研究,详细考察了甲醇用量、催化剂用量、反应温度、反应时间等因素对反应结果的影响,得到较佳的工艺条件:甲醇15 g,离子液体2.5 g,松香5 g,反应温度200 ℃,反应时间4 h.在该条件下,所得产物松香甲酯的酸值为17.4 mg/g;并对离子液体(HSO3-pmim)pTSA的重复使用性能进行了考察,分出的离子液体在不经处理直接重复使用5次时,所得产物松香甲酯的酸值为20.1 mg/g,具有较好的可重复使用性.  相似文献   

6.
制备、表征了酸功能化离子液体1-(3-磺酸)丙基-3-甲基咪唑对甲苯磺酸盐((HS03-pmim)pTSA),并用于催化合成松香甲酯的反应研究,详细考察了甲醇用量、催化剂用量、反应温度、反应时间等因素对反应结果的影响,得到较佳的工艺条件:甲醇15g,离子液体2.5g,松香5g,反应温度200℃,反应时间4h。在该条件下,所得产物松香甲酯的酸值为17.4mg/g;并对离子液体(HSO3-pmim)pTSA的重复使用性能进行了考察,分出的离子液体在不经处理直接重复使用5次时,所得产物松香甲酯的酸值为20.1mg/g,具有较好的可重复使用性。  相似文献   

7.
酸性离子液体催化合成乙酸龙脑酯   总被引:1,自引:0,他引:1  
制备了酸功能化离子液体(3-磺酸基)丙基三乙基铵硫酸氢盐[N(Et)3(CH2)3SO3H]HSO4,并用FT-IR、1HNMR和13CNMR对其进行了表征.将其与氯乙酸组成的复合催化体系用于催化α-蒎烯一步酯化反应,详细考察了离子液体用量、反应温度、反应时间、反应物配比等因素对酯化反应的影响,得到了较佳的反应条件:n(α-蒎烯)∶n[N(Et)3(CH2)3SO3H]HSO4∶n(氯乙酸)∶n(乙酸)5∶0.6∶5∶14,反应温度30℃,反应时间10h.在该条件下α-蒎烯转化率为95.90%,乙酸龙脑酯选择性45.07%.并对催化体系的重复使用性进行了考察,重复使用5次时,α-蒎烯转化率仍达87.4%,乙酸龙脑酯选择性40.6%.  相似文献   

8.
制备了一种酸功能化离子液体1-(3-磺酸基)丙基-3-甲基咪唑磷酸二氢盐((HSO3-pmim) H2 PO4),并用FT-IR、 1 H NMR、 13 C NMR对其进行了表征.将其同氯乙酸构成的复合催化体系磺烷基咪唑磷酸盐-氯乙酸((HSO3-pmim)H2 PO4-ClCH2 COOH)用于催化α-蒎烯水合反应,详细考察了水合反应的影响因素,得到了较佳的反应条件:n(α-蒎烯)∶ n((HSO3-pmim)H2 PO4)∶ n(氯乙酸)∶ n(水) 6∶ 1∶ 6∶ 30,反应温度 80 ℃,反应时间 8 h.在该条件下α-蒎烯转化率为 97%,松油醇选择性 47.1%.并对催化体系的重复使用性进行了考察,该催化体系不经处理直接重复使用5次时,α-蒎烯转化率仍达 83.7%,松油醇选择性 51.6%.  相似文献   

9.
漆酚金属盐高分子复合催化剂催化酯化反应   总被引:11,自引:3,他引:8  
探讨了漆酚金属盐高分子复合试剂催化酯化反应的情况,首先以乙酸和丁醇为反应体系,筛选了最佳催化剂,实验表明,Fe、Al、Ti、Sn等的金属盐与漆酚树脂的复合度剂均能催化酯化2,其中,漆酚Fe^3+和Al^3+盐的复合试剂催化酯化活性最好,重复使用8次后转化率仍为92%。此外,该催化剂还能催化乙酸乙酯、乙酸丙酯、忆知心是等一系列有机酯的合成,转化率为87-97%,且能重复使用。  相似文献   

10.
以离子液体[P123mim]Cl为模板剂,合成了介孔分子筛PNS-7,通过XRD、TEM、SEM和N2吸附/脱附技术对其表征,并与传统的介孔分子筛MAS-7进行对比。结果表明:合成的新型分子筛是典型的六方介孔结构,且具有长程有序性和结晶度佳、孔径分布窄、比表面积高等优点。将PNS-7和MAS-7分子筛用于催化裂解木质素反应中,通过单因素和正交试验考察了反应温度、反应时间、催化剂种类及用量对木质素催化裂解反应的影响,相较于MAS-7分子筛,PNS-7的催化性能更佳,以乙二醇为溶剂,木质素1 g、PNS-7分子筛0.1 g,在180℃下反应3 h,木质素裂解残渣率为27.6%,产物香草酸和香草醛的选择性分别为28.2%和29.6%,此外,PNS-7分子筛具有良好的重复使用性能,重复使用4次,其催化性能未见明显降低。  相似文献   

11.

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.  相似文献   

12.

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.  相似文献   

13.

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.  相似文献   

14.

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.  相似文献   

15.
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。  相似文献   

16.

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.  相似文献   

17.
18.

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.  相似文献   

19.
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.  相似文献   

20.
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

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