阻燃剂四溴双酚A的环境友好合成工艺研究

研究了过氧化氢存在下以双酚A与液溴为原料合成四溴双酚A的工艺条件 ,考察了n(Br2 )∶n(双酚A)、n(H2 O2 )∶n(Br2 )、反应时间等因素对反应的影响 ,并通过正交实验 ,优化了合成工艺条件。实验表明 :n(Br2 )∶n(双酚A) =2 2 0∶1 0 0 ,n(H2 O2 )∶n(Br2 ) =1 10∶1 0 0 ,反应温度15～ 2 5℃ ,每克双酚A加水 3mL时收率接近 99% ,溴利用率达 99%     

界面缩聚法合成四溴双酚A聚碳酸酯的工艺研究

以光气和四溴双酚A(TBBPA)为原料经光气界面缩聚,合成了四溴双酚A聚碳酸酯,并对四溴双酚A与光气投料比、催化剂种类及其用量、分子量调节剂用量4个因素进行考察。优化工艺条件为:四丁基氢氧化铵为催化剂,对叔丁基酚(TBP)为分子量调节剂,n(四溴双酚A)∶n(光气)=1∶1.3,n(四溴双酚A)∶n(对叔丁基酚)=1∶0.028,n(四溴双酚A)∶n(四丁基氢氧化铵)=1∶0.022。该方法操作简单,产品分子量分布窄,易于工业化生产。     

连续法合成四溴双酚A

四溴双酚A是一种优良的溴系阻燃剂.以氯苯为溶剂,液溴/双氧水为溴化剂,采用釜式连续法合成了标题化合物.初步研究表明,较为适宜的工艺条件为:投料比n(双酚A)∶n(溴素)∶n(双氧水)=1∶2.1∶2.1,反应温度60 ℃,平均停留时间40 min,四溴双酚A的单程收率为85.4%,m.p.179.8～181.8 ℃.在此条件下套用溶剂,四溴双酚A的收率在95.0%以上,m.p.178.9～181.5 ℃.     

亚硝酸钠催化氧气氧化溴化双酚A制备四溴双酚A

发展了以亚硝酸钠为催化剂,溴素为溴化试剂,通过分子氧氧化溴化双酚A制备四溴双酚A的方法,这是一个新颖、有效的催化氧化方法。考察了溶剂、温度、n(双酚A)∶n(溴素)、催化剂用量、氧气/空气通入时间以及溴素的滴加速度对反应的影响,确定了最佳的反应条件,即:n(双酚A)∶n(溴素)∶n(亚硝酸钠)=1∶2.15∶0.1,反应温度25℃,反应时间2 h。在此反应条件下,四溴双酚A的分离收率可达95.0%(以双酚A计)。该反应具有溴素的利用率高,原子经济性强,反应副产物仅为水,绿色无污染等优点。     

双酚A型环氧树脂的合成

研究了环氧氯丙烷与双酚A在催化剂氢氧化钠的作用下合成双酚A型环氧树脂的方法。考察了环氧氯丙烷的纯度、氢氧化钠的质量、原料环氧氯丙烷与双酚A的配比等对产品色泽及可水解氯的影响,确定了双酚A型环氧树脂的优化工艺条件:n(双酚A)∶n(环氧氯丙烷)=5.0∶1.0,工艺简单易于生产。     

双酚A双磷酰三聚氰胺的合成工艺研究

以双酚A和三氯氧磷、三聚氰胺为原料合成了双酚A双磷酰三聚氰胺氮-磷复合型阻燃剂。考察了反应温度、反应时间、反应物原料配比对产品收率的影响。结果表明,当第一步反应的反应温度为80℃、反应时间为7h、n(双酚A)∶n(三氯氧磷)为1∶2,第二步反应的反应温度为60℃、反应时间为5h、n(双酚A双磷酰氯)∶n(三聚氰胺)为1∶2时,产品双酚A双磷酰三聚氰胺的平均收率为61.78%,并通过红外光谱和热重分析,表征了产物的结构与性质。     

3-溴-4-羟基苯甲醛合成工艺改进

以对羟基苯甲醛为原料,H2O2/HBr为溴化剂,制备了标题化合物,并对其合成工艺进行了研究.在优化的工艺条件下n(p-HBA)∶n(H2O2)∶n(HBr)=1∶1.2∶1.8,反应温度20 ℃,时间140 min,反应收率达70.04%.该工艺具有操作简单、环境污染少等特点.     

四溴双酚A的合成研究

四溴双酚A以95%无水乙醇为溶剂,以双酚A和溴素为原料合成。在双酚A与溴素摩尔比一定的条件下,通过改变反应时间进行合成实验,结果表明:最佳反应时间2.5 h;在反应时间一定的条件下,通过改变双酚A与溴素摩尔比进行合成实验,结果表明:最佳原料摩尔比1∶2.6。在此反应条件下合成具有高收率,高质量,操作简便等优点。     

亚磷酸三双酚A酯的合成研究

以三氯化磷和双酚A为原料合成了抗氧剂亚磷酸三双酚A酯.探索了反应溶剂、三氯化磷滴加时间、滴加温度及物料配比等反应条件对产率的影响.结果表明:反应溶剂为乙醚,三氯化磷滴加时间为20 min,滴加温度为25℃,物料配比[n(双酚A)∶n(三氯化磷)]为3.00∶1.05.在最适宜工艺条件下所制得的产品为白色固体,熔点为64...     

双酚AF的简便合成

常压下,甲基磺酸催化六氟丙酮三水合物和苯酚,一步合成了双酚AF。优化了反应条件,在n(HFA.3H2O)∶n(PhOH)∶n(CH3SO3H)=1∶3.5∶3.0、回流40h条件下,HFA.3H2O转化率达94%,双酚AF相对于HFA.2H2O的选择性和收率分别为93%和87%。     

A+A2/O工艺处理某工业区污水工程设计

某工业区污水处理厂采用A＋A^2／O工艺,对其工艺流程,设计参数和设计特点作了介绍。并对该工艺的优点和注意事项等进行了总结。     

Why alite stops hydrating below 80% relative humidity

It has been observed that the hydration of cement paste stops when the relative humidity drops below about 80%. A thermodynamic analysis shows that the capillary pressure exerted at that RH shifts the solubility of tricalcium silicate, so that it is in equilibrium with water. This is a reflection of the chemical shrinkage in this system: according to Le Chatelier's principle, since the volume of the products is less than that of the reactants, a negative (capillary) pressure opposes the reaction.     

A method based on isothermal calorimetry to quantify the influence of moisture on the hydration rate of young cement pastes

Cement hydration needs water to proceed and if water is lost by drying, the hydration rate will decrease. This can be of importance in cases when concrete surfaces are exposed to drying so that their strength development will be retarded. We describe a method based on isothermal calorimetry to assess how the rate of cement hydration is influenced by removal of water (drying) at different times up to three days after mixing. Thin samples of cement pastes are hydrated in a calorimeter and at different times exposed to one hour drying periods. The resulting decrease in thermal power following the removal of water is quantified as a measure of the reduction in hydration rate. The mass loss is found by weighing the samples before and after a measurement, and the change in water activity of a sample during drying can be found from the slope of the thermal power during the drying period.     

Highlights on the development of A(2A) adenosine receptor agonists and antagonists

Although significant progress has been made in the past few decades demonstrating that adenosine modulates a variety of physiological and pathophysiological processes through the interaction with four subtypes of a family of cell-surface G-protein-coupled receptors, clinical evaluation of some adenosine receptor ligands has been discontinued. Major problems include side effects due to the wide distribution of adenosine receptors, low brain penetration (which is important for the targeting of CNS diseases), short half-life of compounds, or a lack of effects, in some cases perhaps due to receptor desensitization or to low receptor density in the targeted tissue. Currently, three A(2A) adenosine receptor agonists have begun phase III studies. Two of them are therapeutically evaluated as pharmacologic stress agents and the third proved to be effective in the treatment of acute spinal cord injury (SCI), while avoiding the adverse effects of steroid agents. On the other hand, the great interest in the field of A(2A) adenosine receptor antagonists is related to their application in neurodegenerative disorders, in particular, Parkinson's disease, and some of them are currently in various stages of evaluation. This review presents an update of medicinal chemistry and molecular recognition of A(2A) adenosine receptor agonists and antagonists, and stresses the strong need for more selective ligands at the A(2A) human subtype.     

一种新型喹唑啉酮衍生物A与牛血清白蛋白作用的研究

应用荧光光谱和紫外可见吸收光谱研究了A与牛血清白蛋白间的结合作用,确定了A对牛血清白蛋白的荧光猝灭过程的猝灭机理。测定了不同温度下该结合反应的结合常数,结合位点数,热力学参数。依据能量转移理论确定了A和蛋白间的结合距离。采用同步荧光技术考察了A对牛血清白蛋白构象的影响,并讨论了A与蛋白的结合模式。     

Nd^3＋对二甲氧基甲烷电氧化的促进作用

通过循环伏安法（CV）,计时电流法（CA）和线性扫描法（LSV）对DMM在Pt—Nd^3＋／C催化剂上的电氧化特性进行了研究。结果表明用Nd^3＋修饰的碳载铂基催化剂,能够提高催化剂对二甲氧基甲烷（DMM）的电催化氧化活性和稳定性。     

水性超分散剂的合成及表征

研究了以马来酸酐、苯乙烯为主要原料,以钨酸钠为催化剂,在碱性条件下,在水相体系中使用30％的H2O2溶液作引发剂先环氧化聚合后再与JFC在甲苯溶剂中酯化生成水溶性高分子分散剂,并探讨了酯化度、分散温度对分散性能的影响,同时用分光光度法对其分散性能进行了表征,得到有利于提高分散性能的条件：酯化度控制在30％以下、分散温度为60℃为宜。     

高效液相色谱法在红霉素A肟贝克曼重排反应中的应用

建立了一种用于重排反应工艺监控和测定红霉素6,9亚胺醚及其相关化合物含量的反相高效液相色谱法,色谱柱为150mm×4 6mm,填料InertsilODS-3,粒径5μm,流动相为V(CH3CN)∶V〔c(KH2PO4)=0 033mol/L缓冲溶液〕=30∶70,流速0 8mL/min,柱温30℃;紫外检测波长205nm。该方法能够在12min内快速准确指认重排产物中化学性质差异较大的6种物质:红霉素A6,9亚胺醚、红霉素A9,11亚胺醚、红霉素A9位内酰胺、红霉素A8位内酰胺、红霉素E肟和Z肟,并且贝克曼重排产物在进样量13～100μg显示良好的线性关系(rA=0 9975;rB=0 9994;rC=0 9930)。     

Influence of tapes’ properties on the laser cutting process

Ceramic tapes are used to build 3-dimensional components and microsystems in layer manufacturing. The tapes are individually printed and structured before being stacked and laminated. The structuring process of the tapes affects the maximal resolution of fluidic channels, suspended bridges and beams, which in turn determines the scale of miniaturization of the produced components. The aim of this paper is to investigate if the tape composition can be optimized to improve the cutting resolution of laser cutting, which is a very flexible tool for micromachining. Using the Siemens star pattern, the laser cutting resolution was measured for alumina green tapes of different binder compositions with different laser settings. For all tapes the resolution was better the higher the laser beam velocity. At higher velocity though, a higher number of cutting cycles is necessary to cut the tape. The laser cutting resolution depends on the binder composition, but the laser parameters must also be optimized to achieve high cutting resolution.