Siyanid

Kimyoda siyanid kimyoviy birikma bo'lib, C≡N o'z ichiga olgan funksional guruh. Siano guruhi Hidrosiyan kislotasi deb nomlanuvchi bu guruh azot atomiga bog'langan uchta uglerod atomidan iborat^[1].

Noorganik siyanidlarda siyanid guruhi anion sifatida mavjud −C≡N . Natriy siyanid (NaCN) va kaliy siyanid (KCN) kabi eruvchan tuzlar juda zaharli hisoblanadi^[2]. Hidrosiyan kislotasi, shuningdek, vodorod siyanidi yoki HCN sifatida ham ishlatiladi, sanoatda keng miqyosda ishlab chiqariladigan juda uchuvchan suyuqlik bo'lib, uni siyanid tuzlariga kislotala ta'sir ettirish orqali olinadi.

Organik siyanidlar odatda nitril deb ataladi. Nitrillarda, C≡N guruhi uglerod bilan kovalent bog' hosil qilib bog'lanadi. Masalan, asetonitrilda (CH₃−C≡N ), siyanid guruhi metil bilan bog'langan (−CH₃). Nitrillar tarkibidagi siyanid ionlari ya'ni, siyanogidrinlar juda zaharli modda hisoblanadi.

Bog'lanishi

Sianid ioni ⁻C≡N uglerod oksidi ⁻C≡O⁺ va molekulyar azot N≡N bilan izoelektron. C va N o'rtasida uch tomonlama bog'lanish mavjud. Manfiy zaryad C uglerodda to'planadi.

Hodisalari

Tabiatda

Nigeriyada kassavadan siyanidni olib tashlash.

Siyanidlar ma'lum bakteriyalar, zamburug'lar va suv o'tlaridan tayyorlanadi. Sianidlar ma'lum urug'lar va meva toshlarida, masalan, achchiq bodom, o'rik, olma va shaftolida katta miqdorda bo'ladi^[3]. Tarkibida sianid bo'lgan kimyoviy birikmalar siyanogen birikmalar deb nomlanadi. O'simliklarda siyanidlar odatda siyanogen glikozidlar shaklida shakar molekulalari bilan bog'lanadi va o'simlikni o'txo'rlardan himoya qiladi. Tropik mamlakatlarda yetishtiriladigan kartoshkaga o'xshash muhim oziq-ovqat bo'lgan kassava ildizlari siyanogen glikozidlarni o'z ichiga oladi^[4]^[5].

Madagaskar bambukini iste'molini to'xtatuvchi vosita sifatida siyanid ishlab chiqaradi. Bunga javoban, bambukni iste'mol qiladigan oltin bambuk lemuri siyanidga nisbatan yuqori chidamlilikni talab qiladi.

Yulduzlararo muhiti

Sianid radikali •CN yulduzlararo fazoda aniqlangan^[6]. Siyanogen (CN)₂ yulduzlararo gaz bulutlarining haroratini o'lchash uchun ishlatiladi^[7].

Piroliz va yonish mahsuloti

Vodorod siyanidi kislorod tanqisligi sharoitida ma'lum materiallarning yonishi yoki pirolizlanishi natijasida hosil bo'ladi. Masalan, ichki yonuv dvigatellarining chiqindisi va tamaki tutunida kuzatilishi mumkin. Ba'zi plastmassalar, ya'ni akrilonitrillar tarkibidagi moddani qizdirilganda yoki yondirilganda vodorod siyanidini hosil qiladi^[8].

Kofaktori

Gidrogenaza fermentlari faol joylarida temirga biriktirilgan siyanid ligandlarini o'z ichiga oladi. [NiFe]-gidrogenazalarda siyanidning biosintezi karbamoil fosfat bilan reaksiyaga kirishib, sisteinil tiosiyanatga CN⁻ aylanadi^[9].

Organik hosilalari

IUPAC nomenklaturasida -C≡N funktsional guruhiga ega bo'lgan organik birikmalar nitril deb nomlanadi^[10]^[11]. Nitrilga asetonitrilni CH₃−C≡N misol qilib olishimiz mumkin. Nitrillar odatda siyanid ionlarini hosil qilmaydi va bir xil uglerod atomiga bog'langan gidroksil –OH va siyanid –CN bo'lgan funksional guruhga siyanogidrin (C(–OH)(–CN)) deyiladi. Nitrillardan farqli o'laroq, siyanohidridinlar vodorod siyanidini chiqaradi. Noorganik kimyoda o'z ichiga olgan tuz⁻C≡N ionlari siyanidlar deb ataladi.

Reaksiyalari

Protonatsiya

Vodorod siyanidining pK_a-9,21 ga teng. Siyanid tuzlarining eritmalariga vodorod siyaniddan kuchliroq kislotalar ta'sir ettirilganda vodorod siyanidni siqib chiqaradi.

Gidrolizi

Sianid suvda beqaror, ammo reaksiya 170°C gacha sekin boradi. U siyaniddan ancha kam zaharli bo'lgan ammiak va format hosil qilib gidrolizga uchraydi.

{\ce {CN- + 2 H2O -> HCO2- + NH3}}

Sianid gidrolaza bu reaksiyani katalizlovchi ferment hisoblanadi .

Alkillanishi

Sianid anionining nukleofilligi yuqori bo'lganligi sababli, siyanoguruhlar galoid guruhini (metilxloriddagi xlorid) almashtirish orqali organik molekulalarga osonlikcha birikadi. Umuman olganda, organik siyanidlar nitrillar deb ataladi. Organik sintezda siyanid C-1 ya'ni, funksiyalash qobiliyatini saqlab qolgan holda, uglerod zanjirini bittaga uzaytirish uchun ishlatiladi.

{\ce {RX + CN- -> RCN + X-}}

Ishlab chiqarilishi

Sianidlarni ishlab chiqarishda ishlatiladigan asosiy jarayon kislorod va platina katalizatori ishtirokida metan va ammiakdan gazsimon vodorod siyanidi ishlab chiqariladigan Andrussov jarayonlardir^[12]^[13].

{\ce {2 CH4 + 2 NH3 + 3 O2 -> 2 HCN + 6 H2O}}

Ko'pgina siyanidlarning hosilasi bo'lgan natriy siyanidi vodorod siyanidni natriy gidroksid bilan reaksiyaga kirishishi orqali ishlab chiqariladi.

{\ce {HCN + NaOH -> NaCN + H2O}}

Sianid uchun kimyoviy sinovlar

Sianid miqdorini oltin qazib olishda keng qo'llaniladigan potentsiometrik titrlash usuli orqali aniqlanadi. Uni kumush ioni bilan titrlash orqali ham aniqlash mumkin. Ba'zi tahlillarda qaynab turgan eritmani havo bilan tozalash, bug'larni asosiy absorber eritmaga aylantiradi va asosiy eritmadan chiqadigan siyanid tuzi tahlil qilinadi.

Sifatli testlar

Sianidni zaharli modda bo'lagani uchun ko'plab usullar bilan tekshiriladi. Masalan, benzidin ferrisiyanid ishtirokida ko'k rang beradi. Natriy sintezining filtrat qilingan siyanid eritmasiga qo'shilgan temir (II) sulfat ko'k rangni beradi. DMSOdagi para — benzokinon eritmasi noorganik siyanid bilan reaksiyaga kirishib, fluoresan bo'lgan siyanofenolni hosil qiladi. Agar test ijobiy bo'lsa, UV nuri ta'sirida yashil/ko'k rangni namayon qiladi^[14].

Manbalar

↑ IUPAC Gold Book cyanides
↑ „Environmental and Health Effects of Cyanide“. International Cyanide Management Institute (2006). 2012-yil 30-noyabrda asl nusxadan arxivlangan. Qaraldi: 2009-yil 4-avgust.
↑ „ToxFAQs for Cyanide“. Agency for Toxic Substances and Disease Registry (2006-yil iyul). Qaraldi: 2008-yil 28-iyun.
↑ Vetter, J. (2000). "Plant cyanogenic glycosides". Toxicon 38 (1): 11–36. doi:10.1016/S0041-0101(99)00128-2. PMID 10669009. https://archive.org/details/sim_toxicon_2000-01_38_1/page/11.
↑ Jones, D. A. (1998). "Why are so many food plants cyanogenic?". Phytochemistry 47 (2): 155–162. doi:10.1016/S0031-9422(97)00425-1. PMID 9431670. https://archive.org/details/sim_phytochemistry_1998-01_47_2/page/155.
↑ Pieniazek, Piotr A.; Bradforth, Stephen E.; Krylov, Anna I. (2005-12-07). "Spectroscopy of the Cyano Radical in an Aqueous Environment". The Journal of Physical Chemistry A 110 (14): 4854–65. doi:10.1021/jp0545952. PMID 16599455. Archived from the original on 2008-09-11. https://web.archive.org/web/20080911131555/http://www-bcf.usc.edu/~krylov/pubs/pdf/jpca-110-4854.pdf. Qaraldi: 2008-08-23. Siyanid]]
↑ Roth, K. C.; Meyer, D. M.; Hawkins, I. (1993). "Interstellar Cyanogen and the Temperature of the Cosmic Microwave Background Radiation". The Astrophysical Journal 413 (2): L67–L71. doi:10.1086/186961. http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1993ApJ...413L..67R&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf.
↑ Anon. „Facts about cyanide:Where cyanide is found and how it is used“. CDC Emergency preparedness and response. Centers for Disease Control and Prevention (2013-yil 27-iyun). Qaraldi: 2016-yil 10-dekabr.
↑ Reissmann, Stefanie; Hochleitner, Elisabeth; Wang, Haofan; Paschos, Athanasios; Lottspeich, Friedrich; Glass, Richard S.; Böck, August (2003). "Taming of a Poison: Biosynthesis of the NiFe-Hydrogenase Cyanide Ligands". Science 299 (5609): 1067–70. doi:10.1126/science.1080972. PMID 12586941. http://pdfs.semanticscholar.org/d359/5a5928df6c6209f88e105c937ccce0a05237.pdf.
↑ IUPAC Gold Book nitriles
↑ NCBI-MeSH Nitriles
↑ Andrussow, Leonid (1927). "Über die schnell verlaufenden katalytischen Prozesse in strömenden Gasen und die Ammoniak-Oxydation (V) [About the quicka catalytic processes in flowing gases and the ammonia oxidation (V)]" (de). Berichte der Deutschen Chemischen Gesellschaft 60 (8): 2005–18. doi:10.1002/cber.19270600857.
↑ Andrussow, L. (1935). "Über die katalytische Oxydation von Ammoniak-Methan-Gemischen zu Blausäure [About the catalytic oxidation of ammonia-methane mixtures to cyanide]" (de). Angewandte Chemie 48 (37): 593–5. doi:10.1002/ange.19350483702.
↑ Ganjeloo, A; Isom, GE; Morgan, RL; Way, JL (1980). "Fluorometric determination of cyanide in biological fluids with p-benzoquinone*1". Toxicology and Applied Pharmacology 55 (1): 103–7. doi:10.1016/0041-008X(80)90225-2. PMID 7423496.

Havolalar

[1] IUPAC Gold Book cyanides

[CMC-2] „Environmental and Health Effects of Cyanide“. International Cyanide Management Institute (2006). 2012-yil 30-noyabrda asl nusxadan arxivlangan. Qaraldi: 2009-yil 4-avgust.

[3] „ToxFAQs for Cyanide“. Agency for Toxic Substances and Disease Registry (2006-yil iyul). Qaraldi: 2008-yil 28-iyun.

[4] Vetter, J. (2000). "Plant cyanogenic glycosides". Toxicon 38 (1): 11–36. doi:10.1016/S0041-0101(99)00128-2. PMID 10669009. https://archive.org/details/sim_toxicon_2000-01_38_1/page/11.

[jones-5] Jones, D. A. (1998). "Why are so many food plants cyanogenic?". Phytochemistry 47 (2): 155–162. doi:10.1016/S0031-9422(97)00425-1. PMID 9431670. https://archive.org/details/sim_phytochemistry_1998-01_47_2/page/155.

[6] Pieniazek, Piotr A.; Bradforth, Stephen E.; Krylov, Anna I. (2005-12-07). "Spectroscopy of the Cyano Radical in an Aqueous Environment". The Journal of Physical Chemistry A 110 (14): 4854–65. doi:10.1021/jp0545952. PMID 16599455. Archived from the original on 2008-09-11. https://web.archive.org/web/20080911131555/http://www-bcf.usc.edu/~krylov/pubs/pdf/jpca-110-4854.pdf. Qaraldi: 2008-08-23. Siyanid]]

[7] Roth, K. C.; Meyer, D. M.; Hawkins, I. (1993). "Interstellar Cyanogen and the Temperature of the Cosmic Microwave Background Radiation". The Astrophysical Journal 413 (2): L67–L71. doi:10.1086/186961. http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1993ApJ...413L..67R&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf.

[CDC-8] Anon. „Facts about cyanide:Where cyanide is found and how it is used“. CDC Emergency preparedness and response. Centers for Disease Control and Prevention (2013-yil 27-iyun). Qaraldi: 2016-yil 10-dekabr.

[9] Reissmann, Stefanie; Hochleitner, Elisabeth; Wang, Haofan; Paschos, Athanasios; Lottspeich, Friedrich; Glass, Richard S.; Böck, August (2003). "Taming of a Poison: Biosynthesis of the NiFe-Hydrogenase Cyanide Ligands". Science 299 (5609): 1067–70. doi:10.1126/science.1080972. PMID 12586941. http://pdfs.semanticscholar.org/d359/5a5928df6c6209f88e105c937ccce0a05237.pdf.

[10] IUPAC Gold Book nitriles

[11] NCBI-MeSH Nitriles

[12] Andrussow, Leonid (1927). "Über die schnell verlaufenden katalytischen Prozesse in strömenden Gasen und die Ammoniak-Oxydation (V) [About the quicka catalytic processes in flowing gases and the ammonia oxidation (V)]" (de). Berichte der Deutschen Chemischen Gesellschaft 60 (8): 2005–18. doi:10.1002/cber.19270600857.

[13] Andrussow, L. (1935). "Über die katalytische Oxydation von Ammoniak-Methan-Gemischen zu Blausäure [About the catalytic oxidation of ammonia-methane mixtures to cyanide]" (de). Angewandte Chemie 48 (37): 593–5. doi:10.1002/ange.19350483702.

[14] Ganjeloo, A; Isom, GE; Morgan, RL; Way, JL (1980). "Fluorometric determination of cyanide in biological fluids with p-benzoquinone*1". Toxicology and Applied Pharmacology 55 (1): 103–7. doi:10.1016/0041-008X(80)90225-2. PMID 7423496.

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