Kaféin

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Cithakan:Chembox LD50
Kafeina
Gambar
Gambar
Identifikasi
Nomor CAS [58-08-2]
Nomer RTECS EV6475000
SMILES C[n]1cnc2N(C)C(=O)N(C)C(=O)c12
Sifat
Rumus molekul C8H10N4O2
Massa molar 194,19 g·mol−1
Panampilan bubuk putih tidak berbau
Densitas 1,2 g·cm−3, padat
Titik leleh

227-228 °C (anhidrat) 234-235 °C (monohidrat)

Titik umob

178 °C (menyublim)

Kelarutan dalam air 22 mg·mL−1 (25 °C)
180 mg·mL−1 (80 °C)
670 mg·mL−1 (100 °C)
Kaasaman (pKa) −0,13 – 1,22[1]
Momen dipol 3,64 D (terhitung)
Bahaya
MSDS External MSDS
Bebaya utama Berakibat fatal apabila terhirup, tertelan
ataupun terserap melalui kulit.
NFPA 704
NFPA 704.svg
1
2
0
 
Titik murub N/A
Kejaba ditélakaké suwaliké, data ing ndhuwur kanggo
ing suhu lan tekanan standar (25°C, 100 kPa)

Sangkalan lan referensi

Kaféina[3][4], utawa luwih kawentar kanthi jeneng kaféin, ya iku senyawa alkaloid xantina wujud kristal lan rasané pahit kang digunakaké minangka obat perangsang psikoaktif lan diuretik ènthèng[5]. Kafeina tinemu déning kimiawan Jerman, Friedrich Ferdinand Runge, nalika taun 1819. Dèwèké gawé istilah "kaffein" kanggo ngrujuk marang senyawa kimia ing kopi.[6] Kafeina uga karan guaranina nalika katemokake ing guarana, mateina nalika katemokake ing mate, lan teina nalika katemokake ing teh. Kabèh istilah kaebut padha-pagha ngrujuk marang senyawa kimia kang padha.

Kafeina ditemoni kanthi alami ing bahan pangan kaya wiji kopi, godhong teh, buah kola, guarana, lan maté. Ing wit-witan, dhèwèké berperan minangka pestisida alami kang nglumpuhake lan matèni gegremet-gegremet katentu kang mangan wit-witan mau. Dhèwèké lumrahé dikonsumsi déning manungsa mengekstraksi saka wiji kopi lan godhong teh.

Kafeina arupa obat perangsang sistem pusat saraf ing manungsa lan bisa ngilangi rasa ngantuk kanthi sewentara. ombenan kang ngandut kafeina, kaya kopi, teh, lan ombenan entheng, disenengi banget. Kafeina arupa zat psikoaktif kang paling akèh dikonsumsi ing donya. ora kaya zat psikoaktif liyané, kafeina legal lan ora diatur déning hukum ing kbeh yuridiksi donya. Ing Amérika Utara, 90% wong diwasa ngombé kafeina saben dina.[7]

Anane[besut | besut sumber]

Sumber utama kafeina donya ya iku wiji kopi. Kandungan kafeina ing kopi variasi banget, tergantung ing jinis wiji kopi lan metode panggawean kang digunakaké[8]. Secara umum, sak sajian kopi ngandut sakiwa-tengené 40 mg (30 mL espresso varietas arabica) kafeina, nganti 100 mg kafeina kanggo sak cangkir (120 mL) kopi. Lumrahé, kopi dark-roast duwé kadar kafeina kang luwih endek amarga prosès pemanggangan bakal mengurangi kandhutan kafeina ing wiji mau.[9][10] Kopi varietas arabica lumrahé ngandut kadar kafeina kang luwih sithik daripada kopi varietas robusta.[8] Kopi uga ngandut pira-pira teofilina, nanging ora ngandut teobromina.

Teh arupa sumber kafeina liyané. Sanajan teh ngandut kadar kafeina kang luwih dhuwur ketimbang kopi, lumrahé teh disiapke sajrone kadar sajian kang luwih endek. Kandungan kafeina uga variasi ing jinis-jinis godhong teh kang béda. Teh ngandut uga ngandut teobromina lan kadar teofilina kang sithik luwih dhuwur ketimbang kopi. Werna banyu teh ora dadi pathokan kang apik kanggo nemtokake kandhutan kafeina.[11] minangka conto, teh kaya teh ijo Jepang gyokuro kang wernane luwih pucet ngandut kafeina kang luwih ketimbang teh lapsang souchong kang wrnane luwih peteng.

Kafeina uga ana sajrone pira-pira ombenan entheng kaya kola. ombenan entheng racaké ngandut sakiwa-tengené 10 nganti 50 miligram kafeina per sajian. Kafeina ing ombenan jinis iki asalé saka bahan ramuan ombenan iku dhéwé utawa saka bahan aditif kang diisakake saka prosès dekafeinasi. Guarana, bahan utama pembuatan ombenan ènergi, ngandut kafeina kanti jumlah teobromina lan teofilina kang cilik.[12]

Coklat kang diisakake saka wiji kakao uga ngandut kafeina. Efek rangsangan kang dikasilake déning coklat asalé saka efek kombinasi teobromina, teofilina, lan kafeina.[13] Coklat ngandut jumlah kafeina kang sithik banget kanggo njalari rangsangan kang padha karo kopi. 28 g sajian coklat susu batangan ngandut kadar kafeina kang padha karo secangkir kopi kang didekafeinasi.

Sintesis dan ciri-ciri kafeina[besut | besut sumber]

Kafeina anhidrat (kering).

Ing taun 1819, kimiawan Jerman Friedlieb Ferdinand Runge kasil ngisolasi kafeinan kang relatif murni kanggo pertama kaline.[14][15] Menurut Runge, ia melakukannya atas perintah Johann Wolfgang von Goethe.[16] Pada taun 1827, Oudry mengisolasi "teina" dari teh,[17] namun kemudian dibuktikan déning Mulder[18] dan Jobst[19] bahwa teina mau arupa senyawa kang sama dengan kafeina.[16] Struktur kafeina berhasil dipecahkan padha akir abad kaping 19 déning Hermann Emil Fischer, kang uga arupa orang kang pertama kali berhasil mensintesis total senyawa ini.[20]

Kabèh atom nitrogen kafeina ing sabenere planar (hibridisasi orbital sp2), nyebapake molekul kafeina sipate aromatik. amarga kafeina kanti gampang diisakakake minangka produk samping prosès dekafeinasi, kafeina racaké ora disentesis kanthi kimiawi.[21] Apabila diperlukan, kafeina bisa disintesis dari dimetilurea dan asam malonat.[22]

Cathetan sikil[besut | besut sumber]

  1. ^ Merupakan pKa untuk kafeina yang terprotonasi. Harry G. Brittain, Richard J. Prankerd (2007). Profiles of Drug Substances, Excipients and Related Methodology, volume 33: Critical Compilation of Pka Values for Pharmaceutical Substances. Academic Press. ISBN 012260833X. 
  2. ^ Peters, Josef M. (1967). "Factors Affecting Caffeine Toxicity: A Review of the Literature". The Journal of Clinical Pharmacology and the Journal of New Drugs (7): 131–141. 
  3. ^ Dudutan Majelis Basa Brunei Darussalam – Indonesia – Malaysia (MABBIM) KERTAS F/SP/5 JKTBM [1]
  4. ^ Padanan istilah glosarium Pusat Basa
  5. ^ Maughan, RJ; Griffin J (2003). "Caffeine ingestion and fluid balance: a review.". J Human Nutrition Dietetics 16: 411–20.  Cite nganggo paramèter lawas |coauthors= (pitulung)
  6. ^ caffeine - Definitions from Dictionary.com
  7. ^ Lovett, Richard (24 September 2005). "Coffee: The demon drink?" (fee required). New Scientist (2518). (Kaunduh 26/11/12)
  8. ^ a b "Caffeine". International Coffee Organization. (kaunduh 26/11/12)
  9. ^ "Coffee and Caffeine FAQ: Does dark roast coffee have less caffeine than light roast?". (kaunduh 26/11/12)
  10. ^ "All About Coffee: Caffeine Level". Jeremiah’s Pick Coffee Co. (kaunduh 26/11/12)
  11. ^ "Caffeine in tea vs. steeping time". 1996.  Paramèter |month= sing ora kawruhan dikiwakaké (pitulung)(Kaunduh 25/11/12)
  12. ^ Haskell, C. F.; Kennedy D., Wesnes K. A., Milne A. L., Scholey A. B. (2007). "A double-blind, placebo-controlled, multi-dose evaluation of the acute behavioural effects of guarana in humans". J Psychopharmacol 21 (1): 65–70. PMID 16533867. doi:10.1177/0269881106063815.  Paramèter |month= sing ora kawruhan dikiwakaké (pitulung); Cite nganggo paramèter lawas |coauthors= (pitulung)
  13. ^ Smit, H. J.; Gaffan E. A., Rogers P. J. (2004). "Methylxanthines are the psycho-pharmacologically active constituents of chocolate". Psychopharmacology 176 (3–4): 412–9. PMID 15549276. doi:10.1007/s00213-004-1898-3.  Paramèter |month= sing ora kawruhan dikiwakaké (pitulung); Cite nganggo paramèter lawas |coauthors= (pitulung)
  14. ^ Friedlieb Ferdinand Runge, Neueste phytochemische Entdeckungen zur Begründung einer wissenschaftlichen Phytochemie [Latest phytochemical discoveries for the founding of a scientific phytochemistry] (Berlin, Germany: G. Reimer, 1820). In Chapter 6 (pages 144–159), Runge details his (partial) isolation of caffeine, which he calls "Kaffebase" (i.e., a base (alkaline substance) that exists in coffee).
  15. ^ In 1821, caffeine was isolated both by French chemist Pierre Jean Robiquet and by a pair of French chemists, Pierre-Joseph Pelletier and Joseph Bienaimé Caventou, according to Swedish chemist Jöns Jacob Berzelius in his yearly journal, Jahres-Bericht über die Fortschritte der physischen Wissenschaften von Jacob Berzelius [Annual report on the progress of the physical sciences by Jacob Berzelius] (Dr. F. Wöhler, trans.), vol. 4, page 180, 1825. Furthermore, Berzelius stated that the French chemists had made their discoveries independently of any knowledge of Runge's work or of each other's work. Berzelius states on page 180: "Cafein is eine Materie im Kaffee, die zu gleicher Zeit, 1821, von Robiquet und [von] Pelletier und Caventou entdekt wurde, von denen aber keine etwas darüber im Drucke bekannt machte." (Caffeine is a substance in coffee, which simultaneously, in 1821, was discovered by Robiquet and by Pelletier and Caventou, by whom however nothing was made known about it in print.)

    In Pelletier's article on caffeine – "Cafeine", pages 35–36 in Dictionnaire de Médecine (Paris, France: Béchet Jeune, April 1822), vol. 4 – Pelletier himself corroborates Berzelius's account: "Cafeine, s. f. Principe cristallisable décovert dans le café en 1821 par M. Robiquet. A la mème époque, cherchant la quinine dans le café, parce que le café, considéré par plusieurs médecins come fébrifuge, est d'ailleurs de la mème famille que le quinquina, MM. Pelletier et Caventou obtenaient de leur côté la cafeine; mais leur recherches n'ayant qu'un but indirect, et n'ayant pas été terminées, laissent à M. Robiquet la priorité sur cet objet. Nous ignorons pourquoi M. Robiquet n'a pas publié l'analyse du café qu'il a lue à la société de pharmacie. Sa publication nous aurait permis de mieux faire connaître la cafeine, et de donner des idées exactes sur la composition du café...." (Caffeine, noun (feminine). Crystalizable substance discovered in coffee in 1821 by Mr. Robiquet. During the same period – while they were searching for quinine in coffee because coffee is considered by several doctors to be a medicine that reduces fevers and because coffee belongs to the same family as the cinchona [quinine] tree – on their part, Mssrs. Pelletier and Caventou obtained caffeine; but because their research had a different goal and because their research had not been finished, they left priority on this subject to Mr. Robiquet. We will ignore why Mr. Robiquet has not published the analysis of coffee which he read to the Pharmacy Society. Its publication would allow us to make caffeine better known and give us accurate ideas of coffee's composition....)

    In Robiquet's article on coffee – "Cafe," pages 50–61 in Dictionnaire Technologique, ou Nouveau Dictionnaire Universel des Arts et Métiers,... (Paris, France: Thomine et Fortic, 1823), vol. 4 – Robiquet gives an account of his research on coffee on pages 54–56, detailing the extraction of caffeine and its properties on pages 55–56.

    Pelletier's elemental analysis of caffeine appears on pages 182–183 of the article: Dumas and Pelletier (1823) "Recherches sur la composition élémentaire et sur quelques propriéte's caractéristiques des bases salifiables organiques" (Researchs into the elemental composition and some characteristic properties of organic bases), Annales de Chimie et de Physique, vol. 24, pages 163–191.

    Berzelius later acknowledged Runge's priority in the extraction of caffeine: Jahres-Bericht über die Fortschritte der physischen Wissenschaften von Jacob Berzelius, vol 7, page 270, 1828. Berzelius stated: "Es darf indessen hierbei nicht unerwähnt bleiben, dass Runge (in seinen phytochemischen Entdeckungen 1820, p.146-7.) dieselben Methode angegeben, und das Caffein unter dem Namen Caffeebase ein Jahr eher beschrieben hat, als Robiquet, dem die Entdeckung dieser Substanz gewöhnlich zugeschrieben wird, in einer Zussamenkunft der Societé de Pharmacie in Paris die erste mündliche Mittheilung darüber gab." (However, at this point, it should not remain unmentioned that Runge (in his Phytochemical Discoveries, 1820, pages 146–147) specified the same method and described caffeine under the name Caffeebase a year earlier than Robiquet, to whom the discovery of this substance is usually attributed, having made the first oral announcement about it at a meeting of the Pharmacy Society in Paris.)
  16. ^ a b Weinberg, BA; BK Bealer (2001). The World of Caffeine. Routledge. ISBN 0-415-92722-6.  Cite nganggo paramèter lawas |coauthors= (pitulung)
  17. ^ Oudry (March 1827) "Note sur la Théine" (Note on theine), Nouvelle Bibliothèque médicale..., vol. 1, page 477-479. Uga delengen: Oudry (1827) "Theïn, eine organische Salzbase im Thee" (Theïn, an organic base in tea), Geiger's Magazin für Pharmacie, vol. 19, pages 49–50.
  18. ^ Gerardus Johannes Mulder (1838) "Über Kaffein und Thein" (On caffeine and theine), Journal für praktische Chemie, vol. 15, pages 280-284.
  19. ^ Carl Jobst (1838) "Thein identisch mit Caffein" (Theine is identical to caffeine), Liebig's Annalen der Chemie und Pharmacie, vol. 25, pages 63–66.
  20. ^ "Nobel Prize Presentation Speech by Professor Hj. Théel, President of the Swedish Royal Academy of Sciences". December 10, 1902. Dijupuk 2009-08-03. 
  21. ^ Simon Tilling. "Crystalline Caffeine". Bristol University. (kaunduh 25/11/12)
  22. ^ Ted Wilson, Norman J. Temple (2004). Beverages in Nutrition and Health. Humana Press. k. 172. ISBN 1-58829-173-1.