字幕列表 影片播放 列印所有字幕 列印翻譯字幕 列印英文字幕 [Dr. Poliakoff] Most chemists are fascinated by what they've always been told, [Dr. Poliakoff] 大多數化學家對於傳言中氫氟酸(HF)會"溶解人肉" that HF, hydrofluoric acid, eats human flesh. 這點感到非常印象深刻. We thought that we should try it. 我們認為我們應該來實驗看看. Now, obviously, we can't try human flesh, 不過很明顯的我們不可能用人肉來實驗, and Brady decided that a chicken's leg, 而Brady決定了用雞腿來代替. that's an uncooked leg from a dead chicken, 這是一隻死雞上取下的生雞腿, is a reasonable approximation to a finger. 用來當作人手指的替代品足夠合理了. We decided that we should try and do a demonstration, 我們決定應該在稍後的實驗當中加上 but with some controls so we could compare them. 一些實驗對照組以做比較用. And what we wanted to know was, what was special about HF? 而我們所最想知道的是, 是什麼讓氫氟酸如此特別? Was it the acid, or was it the fluorine? 是因為它酸的特性, 還是因為其中的氟? So we thought if we took two other acids, 所以我們想準備另外兩種不同的酸, HCl, hydrogen chloride, and sulfuric acid, 鹽酸(HCl), 以及硫酸(H2SO4), both of those have the H, the acid part, but they don't have the fluorine. 這兩種酸都帶有H+離子, 酸性部分, 但都不帶有氟. I have been told that HF attacked your nerves so quickly that if you stuck your finger in it, 我聽說氫氟酸攻擊人體神經的速度極快, 如果你將手指伸進去, and none of us, obviously, would try this, --儘管我們不可能會這麼做-- that it destroyed the nerves really quickly so you could hardly feel anything. 氫氟酸摧毀神經能快得讓你毫無知覺. There are stories of people whose gloves have leaked, 過去某些案例中曾有操作者的手套破損, and they've taken out their hands and bits are missing. 而當他們脫下手套時其中一部分的手指已經不見了. And of course, HF features in the TV show, Breaking Bad, 而影劇"絕命毒師"裡面氫氟酸也曾經出現過, which I'm glad to say I've never seen. 雖然我可以很慶幸地說我還沒看過, [Brady] Why are you glad to say that? It's really good! [Brady] 為什麼要很高興? 這部劇很棒耶! Well, perhaps... perhaps one day I might watch it, when I'm old. 呃, 也許...找時間我會再來看看吧, 等我夠老的時候. After 5 minutes, nothing! 過了五分鐘, 什麼也沒發生! [Brady] Fred; this is 5 minute, 5 minute mark. [Brady] Fred, 到這裡為止是五分鐘的標記. After half an hour, nothing! 過了半小時, 還是什麼也沒發生! [Brady] This is half an hour. [Brady] 到此為止是半小時. At the end of the day, 而到今天的實驗結束時, something slightly might have happened. 似乎出現了一些輕微的變化. We decided to call it a day, but just in case, to leave it overnight in the acid. 我們打算今天先就此作結, 但以防有變, 我們決定直接將雞腿泡在酸中整整一晚. In the morning, it was really interesting. 到了早上, 我們發現很有趣的現象. The two chicken legs in the control acids, HCl, sulfuric acid, 在對照組--鹽酸與硫酸當中的兩隻雞腿, had made quite strong color in the liquid. 呈現了很明顯的顏色變化. And the bits of the chicken leg sticking out still looked quite healthy. 而沒有泡到酸的部位看起來還是相當健康, You could almost imagine cooking them! 你甚至會覺得也許還能夠煮來吃! But the leg in the HF was pale, looked decidedly dead. 但泡在氫氟酸當中的雞腿看起來非常慘白, 看起來完全死透了. So we lifted them out, where the ones in HCl and sulfuric acid had turned rather jelly-like... 所以我們將雞腿取出, 泡在鹽酸與硫酸裡的雞腿部位看起來變得有點果凍狀... [lab technician] Eww. 唉噁... [Brady] Yeah... she's done. [Brady] 好吧, 這全完了. ...and really looked almost like an advertisement for being a vegetarian. ...簡直可以當作推廣素食主義的宣傳廣告了. Really yucky. 相當噁心. But, with the HF, it was quite different. 但是氫氟酸這邊的狀況就相當不同. It was as if a surgeon had chopped the bottom off. 看起來簡直就像動了手術漂亮地切掉了底下的部分. It was moderately interesting what had happened below the surface, 雖然在液面下那端發生了什麼反應的確也很讓人好奇, but really what was much more interesting to me is 但對我而言更有趣的問題在, why the chicken leg in HF looked as if it was dead. 為何泡在氫氟酸裡的雞腿看起來這麼慘白? And, clearly, what had happened is that some of the pigment, 而很明顯的, 必定是其中的某些色素, some of the red color of the meat, had been bleached away. 某些構成肉質紅色的色素, 整個被漂白掉了. The reason that meat is red is because it contains a molecule called myoglobin. 肌肉之所以會呈現紅色是其中包含了叫做"肌紅蛋白"的分子. This is related to hemoglobin, which we have in our blood, 與讓我們的血液呈現紅色的"血紅素"有些關聯, and myoglobin stores oxygen in the muscles, 肌紅蛋白儲存氧分子在肌肉中, and myoglobin is a very similar color to hemoglobin. 讓肌紅蛋白與血紅素具有很相近的顏色. If you cook beef, roast beef, so it's rare, and red juice comes out, the red juice is myoglobin. 如果你烹煮牛排, 或者煎牛排, 其中生牛肉所溢出的紅色肉汁就是肌紅蛋白. Well, in fact, it's myoglobin that's reacted with carbon monoxide, which makes it such bright red. 而事實上, 會讓肉看起來具有鮮紅色的原因就在於肌紅蛋白與一氧化碳結合了的關係. My theory is that the HF is bleaching away, that's, attacking the structure of the myoglobin, 我的理論是氫氟酸破壞了肌紅蛋白的結構而造成了"漂白"的效果, in particular the so-called "heme group", the iron-porphyrin group in the middle, 尤其是被稱為"血基質群"的部分, 為中間帶有鐵配合物的紫質; and breaking some of the bonds, 氫氟酸破壞了其中的鍵結, so that it no longer absorbs light and is colorless. 所以這些基質不再吸收光線而導致看起來無色. And that's why the solution that was left of HF 而這也是為什麼氫氟酸的溶液泡過後 was completely colorless! 看起來還是無色的! It looked as if the stuff had just disappeared, 這看起來就像是浸泡的部分憑空消失, there wasn't any sludge in the HF beaker. 而沒有留下任何殘骸在氫氟酸裡面一樣. [Brady] From school, I thought acid was acid, [Brady] 在學校裡我們學到酸之所以具有酸的特性, and we always learned that H+ is the big deal here and doing all the work, 是因為其中的H+離子的反應所造成的, whether the H+ is coming from hydrochloric acid or sulfuric acid, or hydrofluoric acid. 不論這離子是來自於鹽酸硫酸或者是氫氟酸. Why do they- why do the three all do their work so differently? 但為何這三種酸所造成的反應會這麼不同? The reason is that the chicken leg is made up of a mixture of organic compounds. 原因在於雞腿是一大群有機化合物的混和體, Proteins, a bit of fat, and also bone, which is a mixture of mineral. 蛋白質, 一些脂肪, 還有骨骼--一些礦物質的集合體, Now if you break these organic molecules, 現在如果想要打斷其中的有機分子, you are breaking carbon-hydrogen, carbon-carbon bonds. 就需要打斷其中碳-氫與碳-碳的鍵結. And you can't just break them, you have to, if you like, 而這並不是單純的切斷他們就好, 你需要 cap them off with some other group. 用其他的官能基來打斷這些鍵結. And carbon-fluorine bonds are very strong. 而碳-氟之間的鍵結力非常強大. In fact, HF is not a very strong acid. 事實上, 氫氟酸並不能算是很強的酸, If you dissolve HF in water, especially when it's dilute, 如果你將氫氟酸溶在水中, 尤其是經過稀釋後, it is not as acid as HCl, 它的酸性比不上鹽酸. because the bond doesn't dissociate, the HF bond, quite so much. 這是因為氫-氟鍵的解離性沒有這麼地高. But hydrogen fluoride, HF, is very reactive, 但氫氟酸卻具有非常強的反應性, because although the bond's strong, 這是因為儘管氫-氟鍵是強的, the bonds in the products that you make are even stronger. 你所加入的物質所生成的最終反應物的鍵結要更加強大. [Brady] So in terms of HF having a reputation for being a bad boy, [Brady] 所以簡單來說氫氟酸會這麼惡名昭彰, that's really got nothing to do with its acidity or its hydrogen, it's just the fact it's got fluorine. 其原因並不在於它的酸性或是H+離子, 而是它所帶有的氟囉? [Dr. Poliakoff] It is because it has got fluorine and it will react very easily. [Dr. Poliakoff] 確實是因為它帶有氟而且有極強的反應性. [Brady] Is there anything with fluorine? [Dr. Poliakoff] 不, 因為若現在討論的是, 比方說, 碳-氟之間的鍵結, No, because if you take something with, say, carbon-fluorine bonds, 這個鍵結非常強大而且非常難以分斷. the bonds are so strong that it's very difficult to break them. 它們具有很強的惰性. They are very inert. 舉例來說, 這被應用在冷媒當中, 因為它們相當穩定. They use this refrigerant, for example, because they're very stable. [Brady] 所以這有點像是氟想來邀請氫一同約會, [Brady] So it's a bit like fluorine has come to the dance with hydrogen, 但其實心裡更想找的是找其他人(碳)一樣囉. but *really* wants to dance with someone else. [Dr. Poliakoff] 正是. Precisely. 呃, 事實上它並不是這麼想要約會, 而是結伴共渡一生. Well, it wants not so much to dance, but to bond for life. [Dr. Poliakoff] 我之所以會認為我的理論正確的原因在於, 後來我們一不做二不休, [Dr. Poliakoff] The reason why I think my explanation is correct is because we then went the whole hog, 我們把線切斷, 直接將整隻雞腿泡到氫氟酸裡去了. cut the strings, and dunked the chicken legs completely in the acid.