Newsletter Vol. 15.2

序

活動回顧：

就職典禮

開SemParty

PhotoDay

FirmVisitI

聯校化學學會活動

福利週I

勁過飯

新生註冊日

迎新營

開學晚宴

福利週II

二手書代售

FirmVisitII

就業講座

AcademicArticle

輕鬆一刻

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06

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15

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Vol.15.22013

目錄

Chemistry Society,SS, HKUSU 序

時間已成過去，過去只剩回憶。一年幹事任期，眨眼已逝。

驀然回首，過去一年任期有喜有悲：有成功，亦有失敗；有高峰，亦有低谷；有淚水，但更多的是汗水和一張張滿足的笑臉。這是充滿回憶的一年，但時間太少，遺憾和不捨太多。

沒有人天生就懂「上莊」，很多事情都是邊學邊做。剛「上莊」的我們一竅不通，雖然跌碰不少，但也得著不少。直至今天，縱不能保證參透「上莊」這部艱深的書，但算略有小成的時候，卻發覺一年的光陰已不知不覺地溜走。縱然抱憾，但也感恩。

感恩的是，一年以來雖然有很多地方做得不夠盡美，卻有莊友間的互相扶持和鼓勵。我們一起努力，一起「撻皮」；一起跌倒，也一起重新站起來。傷心的時候，我們互相安慰；快樂的時候，我們互相分享。擔任學會幹事一年，我們失去很多，但得到更多。我們得到了一群好朋友、好戰友，還有一段永不忘記的回憶。

我們感恩的，還有一群熱愛化學學會的會員。沒有你們的支持和建議，我們絕對不能走到今天這地，學會的運作也不能更完善美滿。我們衷心感謝你們的支持。

任期即將終結，盼望這份對化學學會的執著和熱誠能繼續延續下去，綻放化學學會的每一載！

Exothermic熱血幹事

1

就職典禮不知不覺，香港大學學生會理學會化學學會自成立以來已經過了十五個年頭。第十五屆幹事會Exothermic也藉是次就職典禮正式對外宣佈上任。　當晚不少嘉賓蒞臨出席，包括化學系的教職員、港大內各學會及其他院校的代表，場面非常熱鬧。本幹事會亦非常榮幸邀請到幾位教授、講師以及上屆主席致辭。新一屆幹事會亦在台上宣誓，許下他們對會員的承諾。新任主席也在交接儀式上從上屆主席手上接過學會印章後，代表新任幹事會致詞及致送紀念品予嘉賓。在典禮圓滿結束的同時，亦象徵第十五屆幹事會的工作即將展開。

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開SemParty

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為了讓會員能在學期初有一個美好的開始，化學學會於一月尾舉行了一個開SemParty。派對中包含幾個破冰遊戲以及集體遊戲，透過各個遊戲，將派對氣氛推高，同時讓參加者加深對彼此的認識。遊戲過後亦有美味的食物，讓參加者能享受歡愉的一晚。

化學學會於二月舉行了近年來首次的PhotoDay。參加者於月明泉拍下紀念性的一刻，希望能為會員框下大學生活的一點美好回憶。參加者不乏各年級的同學，更包括十名教職員。當天天氣較預期好，為照片素質錦上添花。是次活動反應熱烈，能得到如此支持對我們而言實在是一種鼓舞。

PhotoDay

FirmVisit I

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為了讓會員對化驗所日常工作及其檢驗測試流程有更深入的了解，從以對將來的工作方向作出定位，化學學會於三月舉行了FirmVisitI。我們很高興是次考察可以邀請香港通用公證行和廠商會檢定中心為同學作出深入淺出的講解，同學們的反應都非常熱烈，可見同學們對自己的將來充滿好奇。

中大、科大、浸大、理大、城大.......

在三月至四月間，我們聯同其他大學的化學學會合辦了聯校籃球比賽及足球比賽，讓各院校的化學系同學切磋切磋。六所院校最終能走在一起、進行過二十多場賽事、大家努力爭奪冠亞季軍；比賽完滿結束，乃要感謝每位參賽的足球隊籃球隊成員、以及各位到場支持的啦啦隊。希望是次聯校活動能為各位帶來美好的回憶！

聯校化學學會活動

Welfare Week I

化學學會的第一次福利週於三月尾順利舉行。是次福利週售賣各式各樣的學會產品，包括設計獨特的SocietyT-shirt及精美的Societypaper等等。除了向學會會員派發福利包之外，我們還提供免費的柚子蜜及一元四粒燒賣的優惠，為經過的會員加油打氣。

是次福利週反應熱烈，能夠順利舉行，有賴各會員支持，本學會在此衷心感謝。

福利週I9

為祝福會員能在學期末的考試中勁過，及能以輕鬆的心情迎接考試，化學學會於四月舉辦了以「過三爆四」為主題的勁過飯。當晚活動包括切燒豬、寫揮春，以及派出精心設計的勁過利是。除了這些傳統的活動，為增添新意，我們還準備了有別於傳統的特備環節和遊戲。

勁過飯

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時間飛逝，又是本化學學會迎接各個新面孔的日子。雖然原定兩日的新生註冊日因颱風關係縮減至一天，但也無損幹事會的熱情。為了讓新生對於在香港大學修讀化學有初步了解，幹事會派發自己設計的單張，內容包括修讀化學入門必修課的課程編號、時間表等。一元復始，萬象更新。注入新血的同時，希望新一年化學學會也有一番新景象。

新生註冊日

為迎接新一屆的新生，化學學會於八月尾舉辦迎新日及三日兩夜的迎新營。是次迎新營以特務為主題，希望增加同學的思考能力，同時帶給他們難忘的回憶。

雖然活動一度因天氣而出現阻礙，幸好所有的活動仍能順利在一片歡呼聲中結束，讓新生在大學的路上展開美好的一頁。

迎新營

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開學晚宴

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本學會於九月尾在研究生餐廳舉行了開學晚宴，並邀請到四位化學系教師出席。是次活動旨在提供一個平台讓老師和同學接觸，彼此交流，另外亦希望透過是次活動慶祝新學期的開始。本會希望是次飯宴中的美食，表演及抽獎環節等能給予參加者一個愉快和難忘的晚上。 福利週 II

承蒙各會員的熱烈支持，化學學會於九月尾至十月初舉行學會本年度第二次的福利週。除了第一次福利週所提供的優惠外，我們在各方面都加入新的元素，為求令會員得到更多的選擇。食品方面，除了受大眾歡迎的燒賣外，我們還準備了魚蛋和蟹柳出售；飲品方面，我們也增加了奶茶，以切合同學讀書時的需要。除了派發精緻的福利包之外，我們更推出了最新設計的學會外套供會員選購。

除了一系列的福利活動外，本會更提供其他服務，例如實驗袍及安全眼鏡代訂服務。本會了解到同學上實驗課時需要用到實驗袍及安全眼鏡，特意於新生註冊日及九月初開設櫃檯，讓同學以相宜的價錢購買實驗袍及安全眼鏡。此外，本會安排已訂購實驗袍及安全眼鏡的同學於九月初及福利週II領取，務求令同學趕及實驗課時使用。

本會於十月中舉行二手書代售。本活動提供一個平台讓同學有機會以一個合理的價錢售賣不適用但仍簇新的教科書，以及讓同學在新學年購買二手書。活動原定於九月三十日舉行，但因颱風關係順延，然而亦不減同學參與的踴躍程度。當中大部分的化學教科書售罄，顯示同學們對化學都充滿熱情。

二手書代售

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FirmVisit II

由於會員對FirmVisitI反應十分熱烈，可見同學對將來的工作前境十分關心，因此化學學會於十月舉行了FirmVisitII，更有幸成功邀請了四間不同種類的公司和化驗所（生產力局，香港標準及檢定中心，香港賽馬會賽事化驗所及六福集團中華珠寶鑑定中心有限公司）為同學講解不同實驗室的工作流程，同學們都聽得非常入神。

為了提供一個平台讓會員了解完成化學學士課程後可從事相關職業的資訊，化學學會於十月尾舉行了就業講座。是次講座成功邀請了四位不同工作背景的化學系畢業生為會員作出精采而寶貴的分享。是次講座坐無虛席，會員在問答環節的積極發問更令活動生色不少。

就業講座

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HairColoring

Hair coloring is not just a trend popular among teens, it is also boomingly valued by people of all ages in Hong Kong. There are four types of hair coloring: namely permanent, demi-permanent, semi-permanent and temporary coloring. In this article, we will focus on the permanent coloring.

Chemicals used in permanent coloring01Before we start coloring, four ingredients are needed to make the dye: primary intermediate, coupling agent, oxidizing agent and an alkali.

The primary intermediates are aromatic para compounds, such as 1,4-diaminobenzene(Fig. 1) or 2,5-diaminotoluene(Fig. 2).

There are various kinds of coupling agents(couplers) which are meta-substituted derivatives of aniline. Couplers can be divided into three major classes, each gives a distinguish color (blue, red or yellowish green) when react with the primary intermediate. Hence, different combinations of coupler and primary intermediate give a diverse hair color.

Hydrogen peroxide is usually used as an oxidant. It is used in the first step of hair coloring by oxidizing the primary intermediate to quinone state. While in the final step, hair dye is formed by peroxide oxidation. However, sulfur is lost from the hair with the use of peroxide and causes damage to the hair. Thus, the volume of peroxide use should be limited to 30% or less.

Finally, an alkaline condition is provided by ammonia (an alkali) to maintain hair’s natural pH. Ammonia serves to break down the cuticle layer and open hair shaft pores so that the dye can easily go inside and bond with the hair. The reaction between the dye and the hair increases. Ammonia can also remove the natural pigment of hair effectively. Compared with permanent hair coloring, demi-permanent hair coloring usually employs a weaker alkaline agent than ammonia. Therefore it gives no lightening to the hair during dyeing.

Fig. 1: 1,4-diaminobenzene

Fig. 2: 2,5-diaminotoluene

Fig. 3: Some red(A,B,C), blue(F) and yellowish green(D,E) couplers

Academic Article

written by Lau Ka Lap

Reactions during permanent coloring0223

The primary intermediate and hydrogen peroxide must be mixed just before use so that the permanent dye products form and deposit inside the hair fiber. The first step of reactions is the oxidation of primary intermediate. Here, we use 1,4-diaminobenzene as an example of primary intermediate.

The quinone form of the intermediate then undergoes reaction with a coupler. We will use coupler F in Fig. 3 as an example. Quinonediimine attacks coupler F and the reaction is called electrophilic aromatic substitution.

Side effects of hair coloring03Since most of the dye components consist of irritation and allergy inducing sensitizer, such as 1,4-diaminobenzene, irritation and allergy become the common adverse effect of coloring hair.

Moreover, as mentioned above, the use of hydrogen peroxide and ammonia causes a great damage to our hair due to the loss of sulfur and opening of hair shaft pores. Therefore, colored hair will become rough, dry and delicate. Frequent conditioning of hair is recommended.

In addition, skin discoloration is also one of the problems of hair coloring. Since the protein and pigment in our skin and hair are similar in structure and type, ammonia used may also remove the pigment in skin and cause the certain patches of discolored skin.

Last but not least, from the Journal of the American Medical Association, there is a small risk that coloring hair may lead to cancer. On the other hand, the Cosmetic, Toiletry, and Fragrance Association claimed that the evidence showing the relationship between cancer and hair dye is inconclusive. Hence, whether coloring hair causes cancer is still a controversial topic. Nevertheless,

Fig. 4: Oxidation of 1,4-diaminobenzene (primary intermediate) to quinonediimine.

quite a lot of studies concluded that people, who started dyeing hair before 1980, have a higher risk of developing non-Hodgkin lymphoma since the earlier hair dye was more carcinogenic.

In conclusion, although hair coloring may make you look brighter and livelier, you should also be aware of the adverse effects of it. Think twice before making the decision!

Fig. 5: Reaction of quinonediimine and coupler F (electrophilic aromatic substitution)

Fig. 6: Oxidation of product from the quinonediimine-coupler reaction

Finally, the product formed from the second step undergoes oxidation to give the final permanent dye. The dye goes inside the hair through the pores, then bonds with the hair and gives a permanent hair color.

We can now see that the final structure of the dye depends on different kinds of primary intermediate and the coupling agent.

ReferencesWikipedia. Accessed on 27th of August, 2013. Hair coloring. Retrieved from http://en.wikipedia.org/wiki/Hair_coloringKeratin.com. Accessed on 28th of August, 2013. Permanent hair coloring preparations. Retrieved from http://www.keratin.com/ai/ai016.shtmlNational Cancer Institute. (2011). Hair Dyes and Cancer Risk. National Cancer Institute.Machere. Accessed on 25th of August, 2013. Hair dyeing – “High fashion in coloring” Materia from Lebel Cosmetics (Japan). Retrieved from http://www.machere.com.ua/en/services/hairdressers/coloring/Daniel J. DeNoon. (2004). Hair Dye Linked to Blood Cancer. WebMD Health News.Brain, M. Accessed on 27th of August, 2013. How Hair Coloring Works. Retrieved from http://science.howstuffworks.com/innovation/everyday-innovations/hair-coloring2.htmCarryfitness.com. Accessed on 29th of August, 2013. Side Effects of Hair Dye/Color. Retrieved from http://www.carryfitness.com/side-effects-of-hair-dyecolor/Cancer Research UK. Accessed on 29th of August, 2013. Does hair dye cause cancer?. Retrieved from http://www.cancerresearchuk.org/cancer-help/about-cancer/cancer-questions/does-hair-dye-cause-cancer#myeloma

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輕鬆一刻Interesting Chemistry

不要忘記瀏覽我們的Youtube頻道！

頻道內提供各種有關港大化學的資訊，未來會繼續更新，敬請留意！

http://www.youtube.com/user/HKUChemSoc/

...I TOLD ACHEMISTRY JOKE

BUT THERE WASNO REACTION

The optimist sees the glass half full.

The pessimist sees the glass half empty.

The chemist sees the glass completely full, half with liquid and half with air.

JokesProfessional Humor

CrosswordYour daily dose of puzzling fun

Q:Why can you never trust atoms?

A: Because they make up everything!

If you're not part of the solution, you're part of the precipitate.

" "

Across1 Mostly responsible for the chemistry of an organic molecule. (15)4 A reactive covalent bond. (6)6 The type of alcohol with the group, -CHOH-. (9)7 The third member of the aliphatic aldehyde series. (8)9 A major constituent of Scot pine oil. (6)12 Seeks electrons to form a covalent bond. (12)14 A simple aromatic molecule. (7)15 A good hydrogenation catalyst. (6)18 High melting polyethene. (4)20 A molecule containing the -CO- group. (6)22 The major constituent of the oil from orange peel. (8)23 This term applies to the alkenes. (11)24 These are good examples: methane, propane, butane and ethanol. (5)

Down2 A constituent of the fragrance of ophrys orchids and highly attractive to pollinating bees. (8)3 But-2-ene has a couple of these. (18)5 Can be made by heating ethene to a high temperature under pressure. (10)7 Polyethylene terephthalate (abbrev). (3)8 Made by polymerising tetrafluoroethene (abbrev). (4)9 Polymerise phenylethene (abbrev). (2)10 A molecule of this compound has two carbon atoms and four hydrogen atoms. (6)11 These organic substances can be synthesised by reacting alcohols, under suitable conditions, with a variety of halogen containing compounds. (11)13 Polymerised propene (abbrev). (2)16 Opposite of trans. (3)17 A saturated hydrocarbon. (6)19 A compound which contains nitrogen and can be synthesised by refluxing a halogenoalkane with ammonia in alcohol. (5)21 The most stable geometrical isomer of but-2-ene. (5)22 This manufactured by heating ethene to a high temperature and pressure in the presence of oxygen catalyst. (4)

Crossword taken from http://www.rsc.org/learn-chemistry/wiki/images/6/68/Dr_Davids_Chemistry_Crosswords_Bk1.pdf Answers and more crossword puzzles can be found in the above link.