臺灣博碩士論文加值系統

近年來，由於石化燃料過度使用，使空氣中的溫室氣體大量增加，造成全球氣候異常變遷，因此替代能源的發展越顯重要，其中又以氫能受到各工業發展國家的重視，而投入大量人力資金開發。在眾多儲氫法中，以化學儲氫被認為是最佳的方式，其中硼氫化鈉有相對穩定且安全的特性，此外其理論能源儲存密度也高，但是因其價格昂貴無法普及，因此若能把硼氫化鈉反應後的產物—偏硼酸鈉，回收使其再利用反應成硼氫化鈉將可以大幅降低其生產成本，使其更加普及。
在先前的研究中已證實偏硼酸鈉和硫酸反應可直接生成硼酸，產率約為40%，硼酸三甲酯和甲醇反應可生成硼酸三甲酯也經由GC証實，而硼酸三甲酯則可用工業製程濕式法合成硼氫化鈉。然而在這一連串的程序中，硼酸三甲酯的產率並不高，使這個方法對降低成本沒有什麼助益。產率不高的主因是因為硼酸和甲醇在反應時產生的副產物—水，使硼酸三甲酯再度變回硼酸和甲醇使產率降低，且放置時間越長產物和空氣中的水也會反應變回硼酸和甲醇，所以除去產物中的水和保存是很重要的課題。本研究主要目的即是使用GC來對硼酸三甲酯做定量且改變各種變因來提升硼酸三甲酯的產率，使生產硼氫化鈉整體的成本能夠大幅壓低。

In this work, regeneration of sodium metaborate, one of the main products from hydrolysis of sodium borohydride for generation of ultrapure hydrogen, back to trimethyl borate (TMB), a precursor to sodium borohydride, was studied. The regeneration strategy mainly composed of two stages: one from sodium metaborate to boric acid, and the other from borica cid to trimethyl borate via esterification. X-ray diffractometer (XRD) revealed successful conversion from sodium metaborate, reaction with sulfuric acid, to boric acid. The average conversion rate is about 55%, based on sodium metaborate used. Gas chromatographers (GC) equipped either with flame ionization detector (FID) or Mass Spectrophotometer (MS) were used to determine quantitatively and qualitatively the esterification of boric acid and methanol to yield trimethyl borate. Interestingly, not TMB but also other borane chemicals appeared in the products of the esterification, as revealed by GC-MS. In order to purify the TMB, three-stage distillation was employed. As a result, the yield in average from boric acid to trimethy borate is circa 90%. That is, the total conversion efficiency from sodium metaborate to trimethyl borate near 50%. could be achieved.

摘要…………………………………………………………………I
Abstract……………………………………………………………II
致謝…………………………………………………………………III
目錄…………………………………………………………………IV
表目錄………………………………………………………………VII
圖目錄………………………………………………………………VIII
第一章 簡介……………………………………………………………1
第二章 文獻回顧………………………………………………………5
2-1硼酸三甲酯簡介……………………………………………………5
2-2硼酸三甲酯的製備方式……………………………………………5
2-3硼酸三甲酯的純化…………………………………………………7
第三章 實驗……………………………………………………………10
3-1實驗藥品……………………………………………………………10
3-2實驗儀器及裝置……………………………………………………11
3-3實驗方法及步驟……………………………………………………13
3-3-1設定GC條件………………………………………………………13
3-3-2繪製硼酸三甲酯及甲醇檢量線…………………………………14
3-3-3檢測硼酸三甲酯生成所需時間…………………………………15
3-3-4硼酸的製備………………………………………………………16
3-3-5硼酸三甲酯的製備及純化………………………………………16
3-3-6計算硼酸三甲酯產量與產率……………………………………17
3-3-7 GC-MS鑑定………………………………………………………18
第四章 結果與討論……………………………………………………19
4-1檢量線之繪製………………………………………………………19
4-2製備硼酸三甲酯所需的時間………………………………………20
4-3硼酸的製備…………………………………………………………23
4-3-1冷卻溫度對硼酸產量的影響……………………………………23
4-3-2產物中雜質存在的可能性………………………………………24
4-3-2-1偏硼酸鈉存在的可能性………………………………………26
4-3-2-2硫酸鈉存在的可能性…………………………………………28
4-4硼酸三甲酯的純化…………………………………………………29
4-4-1蒸餾溫度對產量的影響…………………………………………31
4-4-2蒸餾溫度對純度的影響…………………………………………33
4-4-3反應比例對產率的影響…………………………………………34
4-5 GC-MS 的檢測……………………………………………………37
4-5-1純化後與純化前的差異…………………………………………37
4-5-2可能的未知物……………………………………………………39
4-5-2-1推測方式………………………………………………………39
4-5-2-2推測各物質結構………………………………………………40
4-5-3後段的未知物……………………………………………………49
第五章 結論……………………………………………………………50
參考文獻………………………………………………………………51

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