全國中小學科展

化學

一滴溶液的顯微電解世界

Whe we think of chemistry experiments in schools from the view of environmental\r protection, microscopic chemistry experiment with reduced quantity and waste is\r the trend for experiments in the future. It is also the target that everybody shall\r aim for. After many failures and instructions from teachers, I finally successfully\r performed electrolysis of the most micro-volume of one-drop solution. It was also\r unbelievable to perform quantitative test within the electrolysis time of color\r disappear from the blue cupic sulfate solution. \r To clearly see the one-drop solution electrolysis, instrument starts from magnifier\r to self-assembled micro project, then upgraded to the miro-visual screen. It not\r only can record,also plays/shows in the computer. Most importantly, it is the most\r environmental protection effective and also zero pollution microsopic chemistry\r experiment. It is obviously a target of future development trend. \r 我們從環境保護的角度去思考常校的化學實驗時,減量減廢的微型化學實驗已是未來實驗的趨勢,也是大家應共同努力的目標。在多次失敗及老師的啟發下,我終於成功的做到電解最微量的一滴溶液。對於從藍色硫酸銅溶液顏色消失的電解時間裡,還可做定量的檢定感到不可思議! \r 為了更清楚看到一滴溶液的電解情形,儀器的設計由放大鏡到自組顯微投影機,最後進階到顯微視訊的畫面,它不但可記錄下來,而且可在電腦中播放。最重要的是:最環保也最接近零污染的顯微化學實驗,已然是未來可發展下去的目標。

以離子溶液催化醇與酸酐的之酯化反應

在酯化反應中,經由實驗結果,我們發現離子液體對於此反應有催化的效果。離子液體 是在室溫下呈現液態的離子化合物,將醇類與酸酐放入離子液體中有助於酯化反應的進行, 基於這個新的發現,我們開始尋找使用不同種類的離子液體做實驗,選出適當的離子液體, 並且測試離子液體在不同環境下的催化效果,以及適合的使用計量;更進一步,我們找出離 子液體在催化反應之後,將離子液體回收的方法:利用有機溶劑將離子液體和產物分層並萃 取出產物,把離子液體回收再利用,符合現代推動綠色化學的趨勢。接下來我們探討離子液 體對催化反應的擴展性與應用,先由不同結構的一級醇反應到醯胺鍵的生成,最後推展到合 成阿斯匹靈,實驗結果說明,用離子液體做催化劑,也可以成功的合成阿斯匹靈。 We have established for the first time that ionic liquids, which possess the property of Lewis acid, can facilitate acylation of alcohols with anhydrides to form esters with photo-excitation. With the initial finding, we then screen through different types of ionic liquids with varying counter anions, loading, and external light or heat sources to sort out the best reaction conditions. To gain insights into the working mechanism, the dynamic profile of the catalytic reaction was monitored by analyzing the reaction mixture by using ‘H NMR spectroscopy. The ionic liquids can be recovered by extractive separation from the acylation product, which meets the major theme of green chemistry. To extend the substrate scope and applications of the new catalytic process, different functional primary alcohols and amines were further examined. More importantly, we have utilized the new catalytic protocol for the acetylating of salicylic acid, leading to aspirin with high efficiency.

磁場中的離子轉速-探討離子遷移速度變因

帶電的離子受到垂直的磁場與電場作用,會因為受到洛倫茲力而產生有趣的轉動現象。我們利用上述原理設計簡易的裝置設備,探討電解質溶液不同濃度、不同離子電荷數,受到不同離子間靜電力,產生不同的離子移動速度。經由所測量的時間與圓周運動的距離,可計算電解質的絕對遷移速度。由實驗結果推論在固定電場下,當電解質濃度降低,正、負離子間的相互作用力降低,離子遷移速度(migration velocity)加快,莫耳電導率 Λ(mole conductance)也隨之增加。同濃度時,電解質2-1 價型硝酸銅與2-2 型硫酸銅離子強度(ionic strength)不同,2-2型硫酸銅離子強度較大,遷移速度較小,莫耳電導率Λ 也較小。Because of the effect of Lorentz force, charged ion will have interesting rotation under the vertical magnetic and electric field. We use the above principle to design a simple instrument or tool, in order to evaluate and study the formation of different ionic mirgration velocities. The velocity of the charged ion in the instrument is affected by differences in the electrolyte, the charge differences of the ion tested and the differences in electrostatic forces between ions. From the experiment we can deduct that at a fixed constant electric field, when the concentration of the electrolyte is reduced, the interaction of forces between positive and negative ions will be reduced. When the migration velocity of ions increase, the mole conductivity Λ (mole conductance ) will also increase. At the same concentration, the ionic strength between copper nitrate ( 2-1valency type ) and copper sulfate ( 2-2 valency type ) are not identical. Copper sulfate, a 2-2 valency type has higher ionic strength, the velocity is slower and the mole conductivity Λ is also smaller.

溫差電池的熱力學研究與應用

溫差電池中若僅進行的反應,則其電池電壓與溫差成正比,且純粹是利用化學反應將熱能轉換成電能,我們稱之為「典型溫差電池」,由熱力學公式可推導出典型溫差電池的電動勢(ΔS = S(s)—S(aq),S為絕對熵, n為得失電子數,1F = 96487 C ),且得到下列三項推論來說明溫差電池的特殊現象。 (1) 同一溫差電池,其電動勢與溫差成正比 (ε∝ ΔT)。(2) 不同的溫差電池,當溫差一定時,電壓ε 與ΔS 成正比,與得失電子數n 成反比。典型溫差電池中,電解液濃度越小,金屬離子濃度也愈小,會使得ΔS = (S(s)—S(aq))的絕對值變大,因此溫差電池的電壓也就愈大。(3) ΔS 值的正負決定電壓ε 的正負。Cu(NO3)2 及ZnSO4 溫差電池的ΔS 為正值,所以高溫杯為正極;AgNO3 溫差電池的ΔS 為負值,所以高溫杯為負極。因水溶液中陰、陽離子不能單獨存在,所以單一離子水溶液的絕對熵無法求得,但科學家把氫離子水溶液的標準絕對熵定為零,藉以求出其它離子的絕對熵,然而我們測得在一定溫差時典型溫差電池的電動勢ε,再查得金屬的標準絕對熵 S(s),代入S(aq) = S(s) — nFε/ΔT,便可得到離子水溶液的絕對熵。Cu(NO3)2 溫差電池的電解液中若含有1M 或0.5M 的KNO3,電池電壓仍然與溫差成正比, 但卻可獲得較大的電流,我們稱此類溫差電池為「改良型溫差電池」。我們利用改良型溫差電池的原理,自製環保、節約能源、可重複使用的實用溫差電池,以PVC 水管當容器,上、下兩端開口用銅片封住當電極,管內裝海棉及0.125M Cu(NO3)與 1M KNO3 溶液,熱源加熱上層銅片形成溫差,當溫差維持在70℃,電壓約為70 mV,若串聯30 個實用溫差電池,電壓可達2 V 以上,就可以對鉛蓄電池充電。實用溫差電池的熱源可由回收冷氣機、工廠的廢熱,或直接利用太陽能來當熱源。 If the temperature difference cell only goes through the following reaction Then the potential created by the cell is proportional to the temperature difference, and such a reaction purely changes the thermal energy into electrical energy through chemical reaction, which we often name it “typical temperature difference cells”. We can come to the following formula for the typical temperature difference cells through a series of thermodynamic formula: ε= ΔT . ΔS/ nF (ΔS = S(s)—S(aq), where S is the standard 3 entropy, and n is the number of electrons gained or lost, and 1F = 96487 C). We also provide the following three inferences to demonstrate the special phenomenon for the temperature difference cells: 1. Within the same temperature cell, the electromotive force (EMF) is proportional to the temperature difference. 2. When the temperature difference keeps constant, the electromotive force is proportional to the ΔS in different temperature cells, and is inversely proportional to the number of electrons gained or lost. Within the typical temperature difference cells, when the concentration of the electrolyte becomes more diluted, the concentration of the metal ions also proportionally become lower, which will make the absolute value of the following equation bigger, as a result, will make the electric potential of the temperature difference cells bigger: ΔS = (S(s)—S(aq)) 3. The value of ΔS decides the value of the electromotive force. The ΔS of the following temperature difference cells is positive value: Cu(NO3)2 and ZnSO4 . As a result, within the copper and zinc temperature difference cells, the higher temperature glass is the anode. On the other hand, the ΔS of the AgNO3 temperature difference cell is negative, which means that within the silver temperature difference cell, the higher temperature glass is the cathode. Meanwhile, because the cations and anions can not exist alone, therefore, it is not possible to find the standard entropy of the single ion solution. However, scientists define the standard entropy of the solution containing hydrogen ion to be zero, as a result, we only have to determine the electromotive force for a typical temperature difference cell, while keeping the temperature difference constant, followed by finding the standard entropy for the said metal S(s). Inserting it into the following equation to find the standard entropy for the ion solution. S(aq) = S(s) — nFε/ΔT If the electrolytes for the Cu(NO3)2 temperature difference cell contains 1M or 0.5M KNO3 , the electromotive force is still proportional to the temperature difference, and we can obtain bigger electric current. We call this kind of temperature difference cells “improved version of the typical temperature difference cells”. We try to make more environmental, energy saving, and recyclable temperature difference cell by applying the theory of the improved version of the typical temperature difference cells. We use PVC water pipe as the containers, both edges of the pipe sealed with copper metals, also work as the electrodes. Within the pipe filled with sponge and 0.125M Cu(NO3) and 1M KNO3 solution. The heat source keeps heating the upper copper metal to keep constant temperature difference. When the temperature difference is kept around 70℃, the electric potential is 70 mV. If we can connect 30 practical temperature difference cells in a series, the electric potential will reach 2V, which can then charge the lead rechargeable battery. The heat sources of the practical temperature difference cells can be supplied by the recycled air conditioners, heat waste from a factory, or directly comes from the solar power.

線鋁之情-以陽極氧化鋁模板製作氧化亞銅奈米線

我們使用陽極氧化鋁(AAO)模板來製備銅及其氧化物的奈米線。以硫酸銅和乳酸配製電鍍液,利用氫氧化鈉水溶液(NaOH)將其pH 值調整到12,供以不同電壓,可電鍍出銅及氧化亞銅奈米線。在較高電壓下可製備出銅奈米線,而在較低電壓下可製成氧化亞銅奈米線,若使用中間電壓則能製得銅及氧化亞銅的混合態。利用x 光繞射分析儀(XRD)來分析其結晶構造、使用場發射掃描式電子顯微鏡(SEM)以得知其表面形貌。電鍍出的奈米線直徑約60 nm。奈米線的長度可藉由調整電鍍時間或電壓來控制。在製作IC 內部導線方面,銅奈米線深具開發潛能;在提升太陽能電池的轉換效率、製作可見光光觸媒方面,氧化亞銅奈米線極具前瞻性。We electrodeposited copper and cuprous oxide (Cu2O) nanowires with anodic aluminum oxide (AAO) templates. Both Cu and Cu2O nanowires could be prepared with an alkaline cupric lactate solution, which was adjusted to pH 12 using a 6 M NaOH, when supplied with different electrolytic voltages. Cu nanowires could be prepared when a higher voltage was supplied, and Cu2O nanowires could be prepared with a lower voltage. A mixture of Cu and Cu2O nanowires could be prepared with a supply of a voltage in between. X-ray diffraction (XRD) is used to determine the phase composition, and scanning electron microscopy (SEM) is employed to characterize the morphology of the nanowires. The length of nanowires can be controlled by adjusting the time spent on electrodeposition and the voltage supplied. The resultant diameter of the nanowires was about 60 nm. Cu nanowires are promising materials for making the conductive wires in IC, and Cu2O nanowires hold great promise for improving the conversion efficiency of solar cells and manufacturing visible-light photocatalyst.

聚對位苯基乙烯高分子發光二極體性能研究

高分子發光二極體為導電高分子之熱門研究課題,因其有低成本、製程簡易、可大面積化之優點為無機高分子發光二極體所缺乏,所以受到學術界與工業界之注目。由於高分子發光二極體其有廣視角、高答應速度、低驅動電壓、可製成撓曲式元件等特質,極具成為下一世代顯示器之潛力。高分子聚苯胺為高分子發光材料中,具有低驅動電壓與高發光效率之優點,故本研究將之選為電洞傳遞層材料。但唯一缺點就是不易溶於溶劑中,所以在實驗驗中有安排質子酸摻雜的步驟,就是為了要改變高分子的電性、磁性、光學性質或結構,同時導電度也隨之增加。本研究以ITO基板改質及無電極電鍍為研究主軸,以此來增加其之性能。改質ITO基板目的,是希望使得ITO陽極表面平坦化且可促使電洞注入,進而增加發光層材料附著力與阻隔電子直接導入陽極之特性,故可增加元件之發光亮度。而使用無電極電鍍法,因為其不須通電就能進行電鍍的反應,行成的薄膜也很均勻。所以採用無電極電鍍法,來完成電鍍的步驟。The polymer light emitting diodes is one of the most important study projects in the field of the conducting polymer due to the low production costs、 simple production process、great surface products that the organic light emitting diodes can not achieved. The purpose of this study is try to utilize the polyaniline as the electric hole transfer layer, and the MEH-PPV as the light emitting layer. The disadvantages of the polyaniline are the low solubility in solvents that was improved by doping proton acids. The performance of the indium-tin oxide was improved by the self-assembling method that made the surface of the ITO became more smooth to help the electric hole injection of electrions. And the aluminum cathode was produced by the electrode less plating.

鐵基奈米顆粒製程及物性分析

超導體具有兩大特性 - 抗磁性及零電阻,若善加利用便能大量減少能量損\r 失。不過目前發現的超導體有的結構太複雜,其他則是臨界溫度太低。一年前科\r 學家發現不同於以往銅氧組成的鐵基超導體(FeSe),結構簡單但其臨界溫度仍\r 然太低。故我們利用原料濃度比例不同的Fe 及Se 以TOPO 熱熔法析出奈米顆\r 粒,分析其超導性質。結果顯示Fe 比Se 難析出,故Fe 濃度應比Se 多,且在油\r 性水域中較好混合。

醇醇躍動的振盪反應

震盪反應有許多種反應類型,至今已被完整探討,但對於震盪反應之催化系統,卻鮮少有文獻提及,本研究小組偶然發現,醇類對於震盪反應具有明顯的催化作用,本文嘗試探討各級簡單的醇類對於震盪反應影響,並透過活化能的改變了解醇類在催化過程中所扮演的角色。The many types of BZ oscillation reaction have already been thoroughly discussed. However, little mention has been made in literature regarding the catalysis system of the reaction. The researchers have accidentally found that alcohols exert an obvious effect on the oscillation reaction. The study attempts to discuss the different influences that various kinds of alcohols have on the oscillation reaction and to understand the role alcohols play in the catalytic process through the change of activation energy.

光觸媒(TiO2)對還原重金屬離子之研究

光催化氧化反應以半導體金屬氧化物為催化劑,進行有機性空氣污染物之快速分解反應。其原理係將半導體材質(如:二氧化鈦,TiO2),在適合之光能量照射下,將半導體激發成為具有氧化/還原能力之催化劑,可加速氧化還原反應之進行,迅速分解有機污染物。 研究動機在於利用TiO2在紫外光的照射下,將H2O 分解產生自由基,使其和水中的重金屬離子進行氧化還原反應,期待可以還原水中的重金屬藉以降低水中重金屬離子濃度,同時藉由使用界面活性劑對奈米微粒具保護作用,可回收重金屬奈米微粒。 由實驗結果得知在紫外光照射下,TiO2 使用量0.5 克,AgNO3(aq) 0.01M,照光24 小時其電導度值上升最多且在溶液表面觀察到銀白色銀金屬薄膜生成而所測得銀金屬析出量明顯增加。探討超音波振盪對TiO2還原力的影響得知,超音波震盪的時間越久,所上升的電導度值愈多。 探討常見的界面活性劑(陽離子型及陰離子型)對TiO2還原力的影響:從數據中可觀察到,加入陰離子界面劑時,電導度值明顯上升;而加入陽離子界面活性劑後,電導度值迅速下降,照光後電導度值也不理想。 探討日光及不同頻率的紫外光照射光源對TiO2還原力的影響:發現紫外光的波長愈短,銀金屬析出的量愈多。 探討除氧處理之溶液對TiO2 還原力的影響得知,除氧處理後所配製的AgNO3(aq)0.01M, 經照光24 小時後電導度值明顯上升,且在溶液表面觀察到大片銀白色銀金屬薄膜生成而所測得銀的析出量也大幅增加。 ;In the experiment, we used the properties of T i O 2 that can catalyzed by UV rays and breaking the molecules of water and produce free radicals, which free radicals can redox metallic oxide as accelerator to analyze organic pollutant briskly. We use different shinning time and to find the best effect of the redox reaction . So we want to use this attribute to begin the redox reaction with the metal ion (for example: Ag+) in water, expecting to reduce them. And then we can use this method to recycle the metal and to reduce the pollution in rivers. Throughout shining UV rays in 24 hours, we can find out the best effect of TiO2 reducing the metal ion solution. We can also find that we use ultrasonic first; the more redox it will have. In this research ,we can observed that if we put more anion surface-active agent, the more redox it will have. We find the effect of UV rays is better than visible light. The most important is that we deoxidize the metal ion solution, we can get the best effect of the redox reaction . In our research,we can't get the satisfing result of the copper sulphate (CuSO4) by TiO2 accelerating the redox reaction under UV rays.

瓦斯熱水爐一氧化碳觸媒轉化器之研究

瓦斯熱水爐使用大火時廢氣的CO 濃度非常高是導致一氧化碳中毒事件的關鍵原因,要解決這個問題觸媒轉化是一種可行的方式。影響觸媒性能的因素中以活性中心的種類最為重要,我們發現對轉化一氧化碳為二氧化碳的反應而言鈷有最好的催化效果,其次分別為:鎳、銅、鐵。最好的載體是三氧化二鋁,鈷的含量使用10%,煅燒溫度使用300℃可兼顧性能與成本。 本研究中所研發的 Co/Al2O3 觸媒具備有實用的潛力,可以在空間速度高達1000min-1 的情況下將濃度14,632ppm 的CO 百分之百轉化為CO2,而僅需233℃的反應溫度。因此,應該可以應用在瓦斯熱水爐上以降低一氧化碳中毒的風險。 The incorrect usage of a natural gas powered water heater always generates high carbon monoxide concentration in a closed environment. The dangerous CO gas can be fatal to the careless user of the water heater. Catalytic conversion of CO to CO2 can be a convenient method to solve this problem. The effect of the support, the supported metal, loading of the metal, reaction temperature, gas concentration, and reactants flow rate on the performance of the CO oxidation catalysts have been investigated. X-ray diffraction, gas adsorption and Infrared spectroscopy were applied to study the characteristics of catalysts. A 100% conversion of CO to CO2 can be achieved when 1.46% CO/6% oxygen/N2 reactants was catalyzed by a 10% Co/Al2O3 catalyst at 233℃ with a space velocity of 1000min-1 . This reaction condition is sufficient to remove the entire CO generated by a family-sized natural gas water heater.