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1.
在反应机理的指导下,采用醋酐过量抑制乙醋副反应的发生,研究了以苯磺酸为催化剂的二醋酸亚乙酯裂解制醋酸乙烯的反应动力学规律,得到描述该反应过程的动力学数学模型。  相似文献   

2.
以醋酸甲酯、合成气为原料,碘化铑为主催化剂,碘甲烷为助催化剂,碘化锂、醋酸锂为促进剂,醋酸锌为裂解催化剂,一步合成醋酸乙烯,考察了反应温度、压力和时间对醋酸甲酯转化率和产物选择性的影响。结果表明,随着反应温度的升高、H2分压的增大以及反应时间的延长,醋酸甲酯转化率和醋酸乙烯选择性均先增大后减小;随着CO分压的增大,醋酸甲酯转化率逐步增大,醋酸乙烯选择性先增大后减小。最佳反应条件为:反应温度180 ℃,CO分压2.0 MPa,H2分压2.5 MPa,反应时间6 h;在此反应条件下,醋酸甲酯转化率达到87.26%;醋酐、二醋酸亚乙酯和醋酸乙烯的选择性分别为30.14%,26.57%和5.44%。在间歇反应釜中进行了醋酸甲酯与合成气一步合成醋酸乙烯过程的本征动力学研究,建立了幂函数型动力学模型,回归了动力学模型参数,并经检验证明模型是合适的。  相似文献   

3.
对二醋酸亚乙酯(EDA)在B催化剂作用下裂解制醋酸乙烯过程中可能发生的副反应进行了研究,提出了抑制副反应的工程手段,为该技术的工业放大提供了工程经验。  相似文献   

4.
讨论了加热时间、温度和热速率对煤裂解行为的影响。探讨了煤裂解的单一反应模型和多重反应模型,测定了两种模型的动力学参数,研究了用四氢化萘预处理对煤快速热解的主要影响因素。  相似文献   

5.
甲基叔丁基醚(MTBE)裂解是一条比较理想的生产高纯度异丁烯的工艺路线。采用管式反应器,在170~230 ℃、0.2~0.6 MPa、液相空速0.5~2 h-1的条件下,对SPC-01型固体杂多酸催化剂上甲基叔丁基醚裂解制异丁烯的工艺进行了研究,考察了操作条件对裂解过程的影响。当反应压力为0.4 MPa、反应温度为210~230 ℃、液相空速为0.5~1.0 h-1时,MTBE转化率高于92.2%,异丁烯和甲醇选择性均大于99.9%。采用一维平推流积分反应器模型建立幂函数裂解动力学方程,利用最小二乘法对动力学实验数据进行参数拟合,获得了裂解动力学方程,并对模型进行了检验。  相似文献   

6.
通过对热裂解基本反应步骤的分析,得到其反应动力学常数只与反应前后分子特性有关,而与反应分子的大小无关。通过文献数据求得基本反应速率常数,进而在已建立的延迟焦化主反应网络基础上,计算出反应网络各个分子间的反应动力学参数,为延迟焦化动力学模型的建立奠定了基础。  相似文献   

7.
研究了2,4-二氨基甲苯和二甲基二硫在三苯基磷卤化亚铜络合物催化剂上合成二甲硫基甲苯二胺(DMTDA)的反应动力学。2,4-二氨基甲苯烷硫化反应是由平行连串反应组成的复杂反应体系,当搅拌速度较高,催化剂粒径较小时,催化剂的内扩散和外扩散对反应的影响可以消除,2,4-二氨基甲苯炕硫化反应可以看成由平行连串反应组成的双分子反应组成,并由此建立了动力学模型,对2,4-二氨基甲苯和二甲基二硫而言,反应级数均为一级,并求出了反应的活化参数。  相似文献   

8.
对甲氧基肉桂酸乙酯的合成研究   总被引:8,自引:0,他引:8  
目的与方法 以对甲氧基苯甲醛为原料,醋酸铵为催化剂,经Knoevenagel反应,采用微波辐射技术合成了中间体对甲氧基肉桂酸,再以对甲苯磺酸为催化剂,经酯化反应得对甲氧基肉桂酸乙酯,结果与结论 两步反应的产率分别为87.8%和91.0%,产品结构经IR和^1H-NMR(CDCl3)确证。  相似文献   

9.
目的:测定人血清脱金属铁传递蛋白裂解焦磷酸键的反应速率常数.方法:应用31P NMR技术,在不同pH值及不同浓度MgCl2存在条件下,测定了脱金属铁传递蛋白与焦磷酸二钠反应的核磁共振图谱,根据焦磷酸盐的摩尔浓度(对应于其谱峰强度)随时间的变化情况,应用动力学公式对数据进行拟合.结果:当人血清脱金属铁传递蛋白(0.5~1.0 mmol/L)与焦磷酸盐的反应摩尔浓度比为15时,在312 K条件下,反应速率常数分别为:8.83×10-4 L·mmol-1·h-1(pH 6.85)、9.59×10-4 L·mmol-1·h-1(pH 7.40)和1.38×10-3 L·mmol-1·h-1(pH 8.15).在2 mmol/L MgCl2存在时,pH 7.40、312 K条件下,反应速率常数为1.21×10-3L·mmol-1·h-1.结论:人血清脱金属铁传递蛋白能缓慢地将焦磷酸根裂解为磷酸根,反应具有二级反应动力学性质,Mg2 对该裂解反应有弱催化作用.  相似文献   

10.
用恒温盐浴法测定了辽河和管输减压渣油热裂解反应的转化性能,用简单的热裂解反应动力学模型对实验结果进行了关联,并求取了该模型的动力学参数。结果表明,热裂解动力学模型计算结果与实验结果能很好吻合。  相似文献   

11.
FOR anesthesiologis s ,treatingpostoperativepainhas alwaysbeen a problem.Althoughopioidshave been provedtobe effective,theirsideeffectscouldnotbeignored.With thedevelopmentofscienceand pharmacology,many drugs with aspectsof satisfactoryanalgesicefficacyand couldbe welltoleratedby patientshave been developed.And lornoxicamisone of them, which isa non-steroidalanti-inflammatorydrug (NSAID ), with analgesic, anti-infl-ammatory,andantipyreticproperties.Itseliminationhalf-time(3 to 5 hours) isle…  相似文献   

12.
Dr.Zhang Ren,the chief physician,is the chairman of Shanghai Acupuncture and Moxibustion Association.Having been engaged in medicine for about 40 years,he is experienced in treating various intractable diseases.In his long years of clinical practice,he advocates taking the TCM differentiation as the basis to seek for the acupuncture method for treatment of modern intractable diseases.The author of this essay had the fortune to follow Dr.Zhang in study.The following is a summary of Dr.Zhang's experience in the acupuncture treatment for different intractable diseases with the same therapeutic principle.  相似文献   

13.
In treating chronic nephropathy,Luo Lingjie,a chief physician,pays attention to regulating the balance between yin and yang,treating infection if present,and removing pathogenic factors.He prescribes gentle drugs and uses carefully strongly warming-tonifying ones,emphasizes the importance of persuading the patient to persist in treatment with medication and nurse one's health for recuperation,and is good at combined use of TCM and western medicine therapy and brings the merits of various therapies into full play,with obvious theraoeutic effects.  相似文献   

14.
Objective: To observe the therapeutic effects in acupunture treatment of primary dysmenorrhea combined with spinal Tui Na, and study its mechanism. Methods: Thirty cases of the treatment group were treated by acupuncture combined with spinal Tui Na, and thirty cases in the control group were treated by routine acupuncture. Results: The total effective rate was 93.3% in the treatment group, and 73.3% in the control group, with a significant difference between the two groups (P<0.05). Conclusions: Acupuncture combined with spinal Tui Na has good prospects for treatment of primary dysmenorrhea.  相似文献   

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16.
目的 探讨猪肺磷脂注射液联合经鼻持续气道正压通气(NCPAP)对呼吸衰竭早产儿的临床疗效及肌酸激酶同工酶活性(CK-MB)的影响.方法 选取呼吸衰竭早产儿80例,分为观察组和对照组各40例.对照组采用NCPAP给氧治疗,观察组给予NCPAP给氧联合猪肺磷脂气管内给药.观察两组患儿治疗前及治疗12h、24 h后PaO2、PaCO2、血氧饱和度(SaO2)、pH的变化情况,检测治疗前及治疗5d后血清CK-MB水平;评估两组患儿的临床治疗效果.结果 两组患儿PaO2、PaCO2、SaO2、pH比较,差异均有统计学意义(P<0.05),其中观察组治疗后的PaO2、SaO2、pH均高于对照组,PaCO2则低于对照组.两组的PaO2、SaO2、pH均随观察时间延长而升高(P<0.05),PaCO2均随观察时间的延长而降低(P<0.05).观察组治疗有效率为87.5%,显著高于对照组的70.0% (P <0.05).治疗5d后两组患儿血清CK-MB水平均较前降低(P<0.05),且观察组明显低于对照组(P<0.05).结论 猪肺磷脂注射液气管内给药联合NCPAP可以显著降低呼吸衰竭早产儿CK-MB的含量,提高治疗有效率,起到很好的呼吸循环支持作用.  相似文献   

17.
Evidence obtained from randomized controlled trials (RCTs) has been generally accepted as the gold standard in the evaluation of clinical effectiveness. Readers need to understand the trial design, implementation, results, analysis and interpretation, so as to fully Jnderstand the results of RCTs. Thus, the investigators of RCTs have to report these items in a complete, accurate and clear manner. Since 1998, we have conducted several evaluations on the reporting quality of RCTs published in Chinese journals on traditional Chinese medicine (TCM) and results have shown that there is an urgent need for higher quality RCTs on TCM.  相似文献   

18.
Ankylosing spondylitis is a chronic and progressive disorder with inflammation mainly involving the central axis joints. It mainly affects the cervical spine and the lumbosacral area, with the pathogenesis closely related to the kidney and the Governor Vessel (GV). TCM holds that the syndrome is deficiency in origin and excess in superficiality, which is due to insufficiency of the kidney, deficiency of GV, and blocking of the channels with the invasion of exogenous evil, leading to poor circulation of qi and blood and malnutrition of the bones, muscles and joints. The TCM method of tonifying the kidney and strengthening GV to regulate circulation of qi and blood and check the arthralgia pain should be adopted, with the Kidney-Tonifying and GV Strengthening Decoction (益肾强督汤) prescribed.  相似文献   

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CHEMOTHERAPY playsa greatrolein the treat- ment of malignanttumors,especiallyingynecolo- gicalones.But inanticancerchemotherapy,leuko-cytopeniaisfrequentlytheprimarydose-limitingsideeffect factor.Moreover,cancersarefrequentlychemoresistantbe-causeof overexpressionof P-glycoprotein(P-gp), which isencodedby multidrugresistancegene (MDR1 ) and detectableinup to50% ofhuman cancersand renderscellsresistancetoanticancerdrugs.The safetyand potentialtherapeuticbenefitof mdr1 gene transferredto h…  相似文献   

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