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1.
在热力学计算的基础上,研究CaCO3在铝酸钠溶液体系中发生反苛化反应的规律.热力学计算表明,低温条件下,CaCO3与游离苛性碱形成Ca(OH)2的反苛化程度较小,而其与Al(OH)4-形成3CaO·Al2Oy6H2O(C3AH6)的反苛化反应显著.CaCO3在纯NaOH溶液中反苛化反应的反应率小于5%,而在铝酸钠溶液中其反苛化率可达50%以上,说明Al(OH)4-对CaCO3的反苛化具有显著的促进作用;CaCO3的反苛化率随温度的升高而升高,随铝酸钠溶液苛性比αk的升高呈先升高后降低的规律,当αk为3时,出现极大值;常压条件下,CaCO3在铝酸钠溶液中发生反苛化反应形成C3AH6,而造成氧化铝损失.  相似文献   

2.
研究了普通石灰和改性石灰吸收HCl气体对应的平衡分压随温度的变化、石灰的热分解规律,以及温度对石灰吸收HCl气体的最大反应率的影响,确定了焚烧炉烟气中HCl气体的最佳干式净化温度.研究表明:随温度升高,石灰吸收HCl气体所对应的平衡分压升高;烟气中CO2分压提高,HCl的平衡分压亦升高,但是改性石灰可在一定程度上消除CO2对HCl吸收的不利影响;当反应产物中有未反应石灰存在时,HCl平衡分压会明显下降.200℃时已达最大反应率的石灰在600℃时仍能继续反应.HCl高温净化温度可确定在600℃左右,并可用改性石灰为吸引剂。  相似文献   

3.
以异维生素C钠发酵液的前体物质2-酮基-D-葡萄糖酸(2KG)为主原料,甲醇为反应物,浓硫酸作催化剂,甲酯化反应4 h后,用碳酸氢钠作催化剂,经内酯化反应生成异维生素C钠(D-VCNa).考察了转化时间、转化温度及原料投料比对产品转化率和质量的影响.结果表明,选用碳酸氢钠作催化剂时,降低反应温度和适当延长反应时间有利于提高产品的转化率和质量.确定了较佳的工艺条件为:n(2KG)∶n(CH3OH)∶n(NaHCO3)=1∶18∶1.1,转化温度55℃,转化时间3 h.在该条件下,异维生素C钠的质量分数达95.5%以上.该法反应温和,转化温度较低,转化过程中料液破坏程度低,粗品质量好,可以进行一道精制得合格产品,收率得到较大提高,成本明显降低,已通过省级科技成果鉴定.  相似文献   

4.
贺连娟 《科技信息》2008,(2):190-191
根据麦草浆黑液石灰法除硅的原理,通过试验研究证实,稀黑液蒸发浓缩后,加入除硅剂Ca(OH)2并充分混合,在一定温度下进行灼烧反应,无需进一步苛化,除硅率和碱回收率便可得到良好的效果,使黑液硅含量降低95%以上,碱回收率也可达到95%左右,大大缓解了碱回收工艺流程中的硅积累现象。  相似文献   

5.
在苛化法制烧碱的过程中,纯碱液(碳酸钠)和石灰乳(氢氧化钙)的苛化作用,一方面反应成苛性钠(氢氧化钠),另一方面析出碳酸钙(俗称苛化泥),作为生产的“废物”而被排走。每生产一吨烧碱,就有一吨半含有杂质的粉末状碳酸钙生成。其实,这种“废泥”只要经过洗涤、脱水、干燥,便可制得质量合格的轻质碳酸钙。它广泛地应用于橡胶、塑料、玻璃、造纸、搪瓷、涂料、医药、日用品等轻、重工业以及保温设备方面。  相似文献   

6.
以6-(4-甲基-3-戊烯基)萘-1,4-二醌为原料,过氧乙酸为氧化剂,通过环氧化反应制备了目标产物6-(2-(3,3-二甲基噁丙环-2-基)乙基)萘-1,4-二酮。产物结构通过1H-NMR、FT-IR和GC-MS分析得到表征和确定。探讨了反应底物、氧化剂以及碳酸氢钠的比例、溶剂、温度、时间等对反应转化率和得率的影响,得到优化工艺条件为:萘二醌、过氧乙酸和碳酸氢钠摩尔质量比为1:3:1.2,以氯仿为反应溶剂,反应温度30 ℃,反应时间5 h。在此优化条件下,可得到目标产物6-(2-(3,3-二甲基噁丙环-2-基)乙基)萘-1,4-二酮的得率为90.7%。  相似文献   

7.
湿法磷酸的脱硫研究   总被引:6,自引:1,他引:5  
采用二次回归旋转组合实验设计方法研究了湿法磷酸脱硫时脱硫剂量及其配比、反应湿度、反应时间等对脱硫率的影响,拟合出反应结束时和存放后硫酸根脱除率的回归方程,经显著性检验表明,回归方程高度显著,拟合程度很好,可用于相应硫酸根脱除率的预测与控制。在诸因素中脱硫剂量最重要,影响最大,反应温度和反应时间对脱硫率也有一定的影响。  相似文献   

8.
无规聚丙烯接枝甲基丙烯酸的合成   总被引:1,自引:1,他引:0  
采用溶液聚合的方法将无规聚丙烯(APP)与甲基丙烯酸(MAA)接枝共聚制得接枝共聚物APPgMAA.讨论了反应温度、反应时间、引发剂BPO浓度、单体MAA浓度对接枝率的影响.结果表明:当聚合反应温度低于120℃时,随着温度的增加,接枝率显著增大;当聚合反应温度高于120℃时,接枝率随温度升高而降低.延长反应时间有利于提高接枝率.最适宜的w(引发剂)为1%,m(MAA)/m(APP)为025/1.利用红外光谱证实了接枝物APPgMAA的存在.  相似文献   

9.
采用正丁基吡啶硫酸氢盐离子液体为催化剂,对棕榈酸和甲醇催化酯化合成棕榈酸甲酯的影响因素进行了研究.试验结果表明:棕榈酸物质的量比为50∶1、反应温度为70 ℃、催化剂用量为6%和反应时间为110 min时酯化率最高,在此基础上进行了正交试验极差分析,各因素对反应酯化率的影响主次顺序为:催化剂用量>反应时间>反应温度>醇酸摩尔比,反应的最佳条件是:催化剂用量为8%,反应时间为130 min,反应温度为70 ℃,醇酸物质的量比为50∶1,在此最优条件下进行验证试验,通过验证试验可测得酯化率为98.63%.根据试验数据进行方差分析表明,反应时间、反应温度、醇酸摩尔比和催化剂用量4个因素的水平变化对酯化率均无显著影响.  相似文献   

10.
为优化蓝藻水热液化制取生物油过程,探索反应条件间的交互影响作用及其反应机理,通过设计三因素三水平响应面分析实验,对反应温度(250~370℃)、反应时间(20~50min)、物料质量分数(5%~20%)及其交互作用对蓝藻水热液化反应产油率的影响进行了研究,并通过分析水相产物中的总有机碳、氨氮含量和生物油中的有机物结构研究了生物油产物中化合物分布转化规律。实验结果表明:产油率随着温度的升高而提高,水相产物中总有机碳回收率显著降低,氮回收率提高;反应时间、物料质量分数升高时氮回收率显著升高,而对总有机碳回收率的影响并不显著。通过对油相产物的傅里叶红外分析发现,生物油含有烷烃和酯类,以及酮、羧酸、烯烃、醇类化合物等。通过二次多项回归模型进行方差分析和回归拟合,得到了蓝藻水热液化制油反应的优化条件为反应温度369.99℃、反应时间40.33min、物料质量分数5%,在此条件下,预测所得的最大产油率为33.73%。  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.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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   

16.
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   

17.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

18.
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   

19.
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   

20.
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   

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