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1.
相转移催化剂对苯甲基化木材制备的影响   总被引:16,自引:1,他引:15  
以NaOH作润胀剂及催化剂,氯化苄作醚化剂,季铵盐作相转移催化剂(PTC),对东北红松进行了苯甲基化改性,研究了碱用量,反应时间,反应温度及PTC用量对PTC作用效果的影响,并用了FTIR,X-射线衍射对苯甲基化木材的微观结构进行了表征。  相似文献   

2.
基于发明专利"一种绿色环保人造木材的生产方法("申请号:201010166601.1),以杨木单板及杨木枝丫材/加工剩余物经粉碎所得粉末为研究对象,按"杨木单板-杨木粉末-杨木单板"层叠模式进行装模后实施无胶模压成形,利用木质材料中的纤维、半纤维及木素在一定温度/压力下的自粘合行为,探索木质复合材料无胶模塑成形的工艺及其复合材料的性能。首先进行单因素试验,研究成形压力、成形温度、成形时间及粉末粒度对复合材料静曲强度及吸水率的影响;然后利用响应面法对在单因素实验基础上选取的成形压力、成形温度、成形时间三个主要影响因素进行响应面实验设计,并以静曲强度、吸水率、弹性模量、抗拉强度及内结合强度五个性能指标为响应值,对三个主要成形工艺参数进行综合优化,得出的参数优化结果为。  相似文献   

3.
江苏杨木人造板的研发与展望   总被引:2,自引:0,他引:2  
在总结江苏杨木加工产业现状的基础上,分析了存在的不足,提出了具有发展强势的人造板产品,包括杨木单板层积材、杨木水泥模板、杨木复合地板、杨木人造薄木、竹木复合层积材、超常厚度中密度纤维板、草木复合中密度纤维板、软质纤维(碎料)板、定向结构板、木(草)塑复合材料、杨木木丝墙体材料和废旧木材人造板等。指出了实现人造板产业持续发展的保证措施,包括优化资源供应,重视无醛胶粘剂的研发,加强木材保护技术的研究,突出技术创新,实施人才、专利和标准战略。  相似文献   

4.
研究了以苯甲酰氯和间苯二酚为原料、液碱为除酸剂,酯化合成然后精制得间苯二酚单苯甲酸酯的工艺.研究了酯化反应中温度、物料配比、pH、间苯二酚水溶液的浓度和反应时间等条件对反应的影响,获得了较佳的酯化工艺条件:苯甲酰氯与间苯二酚的摩尔比为1.15∶1;pH值为7.5;反应温度为25℃;反应时间为1.5 h;间苯二酚溶液的质量分数为10%.酯化反应收率为88.6%.考察了结晶溶剂配比、温度对产品质量和收率的影响,经实验评估得到了较佳的结晶工艺条件:结晶溶剂甲苯的体积(/mL)与初产物的质量(/g)之比为2.5∶1,结晶温度为30℃,结晶收率为95.0%.优化工艺条件下产品的总收率为84.2%.  相似文献   

5.
茯苓液态发酵法中CMP的制备及黏度特性的研究   总被引:1,自引:0,他引:1  
茯苓菌株HD06-10进行液态发酵培养,对所获得的茯苓多糖进行羧甲基化处理,制备羧甲基茯苓多糖(CMP),并采用正交设计法优化其制备条件.另外,对CMP的黏度特性进行研究,探讨影响其多糖黏度的因素:浓度、温度、pH、NaCl等.结果表明,反应最佳条件分别是:反应温度为50℃,NaOH浓度为1%,氯乙酸用量为7g,羧甲基化反应介质为80%乙醇,反应时间为44 h:浓度、温度、pH、NaCl 等因素对多糖溶液黏度有较明显的影响作用.  相似文献   

6.
将竹材在200-400℃无氧环境中热处理3 h,然后对热处理竹材进行苯甲基化改性,探讨了反应时间、NaOH用量、相转移催化剂用量对醚化反应的影响.通过反应后热处理竹材的增重率来表征醚化反应程度,在同样的反应条件下,250℃热处理竹材的增重率最大,并通过FT-IR、XRD对苯甲基产品的微观结构进行了表征.  相似文献   

7.
以香豆胶片为原料,通过单因素及正交实验对香豆胶的羧甲基化条件进行优化,考察了各实验因素对羧甲基化香豆胶水溶液表观粘度的影响,得出了香豆胶羧甲基化的最佳条件:氢氧化钠(NaOH)浓度为0.15mol/L,NaOH与氯乙酸钠(ClCH2COONa)物质的量比为1∶1.25,碱预处理时间45min,反应温度50℃,反应时间4h。同香豆胶原胶相比,改性后的香豆胶水溶液中水不溶物质量分数由35.8%降低到了7.9%,表观粘度显著提高。可为工业化生产羧甲基香豆胶提供实验依据。  相似文献   

8.
沙柳、柠条、杨木的苯酚液化工艺研究   总被引:4,自引:0,他引:4  
以苯酚作液化剂,稀硫酸作催化剂,对沙柳(Salix psammophila)、柠条(Caragana intermedia)和杨木(Populus×Euramericana(Doda)Guineir cv.’I-214)进行了液化实验,分析了反应温度、液比、催化剂用量及液化时间对液化反应的影响。结果表明:(1)在适宜的液化条件下,沙柳、柠条和杨木均能达到理想的液化效果,且杨木比沙柳和柠条更易于液化。(2)反应温度对液化过程的影响最大,液比、催化剂用量等对液化过程也有不同程度的影响。(3)杨木液化适宜的工艺条件为:温度150℃,液比(酚/木)为3,催化剂质量分数7%,时间120 min;沙柳和柠条适宜的液化工艺条件为:温度150℃,液比(酚/木)为4,催化剂质量分数7%,时间120 min。  相似文献   

9.
苯直接羟化制苯酚的新工艺   总被引:1,自引:0,他引:1  
提出了TS-1分子筛为催化剂、十六烷基三甲基溴化铵为相转移催化剂、氨水为调节剂以及双氧水为氧化剂的苯直接羟化制苯酚的新工艺。考察了反应温度、反应时间、氧化剂用量和调节剂种类对苯直接羟化反应的影响。确定了反应的最佳条件,当反应时间为2h,反应温度为313K,氨水、催化剂、双氧水、相转移催化剂、苯五者物质的量之比为2.80:0.10∶2.52∶0.005∶1时,苯酚产率可达66.32%。  相似文献   

10.
丙醛缩合制2-甲基-2-戊烯醛的研究   总被引:1,自引:0,他引:1  
研究了丙醛双分子缩合制 2 -甲基 - 2 -戊烯醛的反应 ,以NaOH水溶液作催化剂 ,重点考察了反应温度、溶剂用量、催化剂浓度、反应时间、NaOH固体 /丙醛 (摩尔比 )对目标产物收率的影响 ,确定了制备 2 -甲基 - 2 -戊烯醛的优化反应条件 :温度 2 93K、溶剂苯 5ml、催化剂浓度 2M、时间 1h、NaOH固体 /丙醛 (摩尔比 ) 2 / 15 ,目标产物 2 -甲基 - 2 -戊烯醛的收率可达 98.4%。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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