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腈鈉

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腈鈉是指類化合物和離子形成的鹽,這類鹽被認為是反應中存在的中間體。腈鈉可由腈和氨基鈉、取代氨基鈉或金屬鈉反應得到。但由於腈鈉的高度不穩定性,其固體的分離特別困難。[1]

乙腈鈉

乙腈鈉(NaCH2CN,Mr=63.0)被認為是一種白色固體,可由乙腈和NaN(SiMe3)2反應得到:[2]

CH3CN + 3 NaN(SiMe3)2乙醚→ NaCH2CN + HN(SiMe3)2 + 2 NaN(SiMe3)2

該反應中,乙腈只有1個氫原子被鈉取代。

由於乙腈的α-H具有一定的酸性,因此與氨基鈉液氨中反應,生成了一種被認為是NaCH2CN·xNH3或(CH2CN)-Na+·xNH3的產物。但當這種化合物在液氨中結晶時,產生的卻是CH3C(=NH)NHNa(的鈉鹽)。[3]

乙腈鈉可以和鹵代烴反應:

NaCH2CN + RX → NaX + RCH2CN

苯乙腈鈉

苯乙腈鈉(C16H13N2Na,Mr=256.3)可由苯乙腈和金屬鈉直接反應得到,其產物為二聚體的鈉鹽:[1]

3 C6H5CH2CN + 2 Na → NaCN + C6H5CH3 + C16H13N2Na

Fred等認為苯乙腈鈉的結構應該是(C6H5)HC=C=N-Na(Mr=139.1)[4]

2 (C6H5)H-C=C=N-H + 2 Na → 2 (C6H5)H-C=C=N-Na
(C6H5)H-C=C=N-Na + H2 → C6H5CH3 + NaCN (副反應)

其化學性質活潑,高溫下發生分解反應,產生二苯乙烯氰化鈉

2 (C6H5)H-C=C=N-Na → NaCN + (C6H5)H-C=C-H(C6H5)

它和空氣中的氧氣反應,得到苯甲酸和氰化鈉:

2 (C6H5)H-C=C=N-Na + O2 → C6H5COOH + NaCN

它和硝酸銀在無水乙醇中反應,得到相應的銀鹽。

腈的其它金屬鹽

乙腈和叔丁基鋰反應,可以得到Li2CHCN。[2]

苯乙腈和鉀的反應可以得到相應的鉀鹽,反應按如下方程式發生:[5]

2 C6H5CH2CN + 2 K → 2 C6H5HC=C=NK + H2

產物C6H5HC=C=NK對水蒸氣和二氧化碳敏感,酸會將其分解,放出氰化氫。它和(C6H5)(CN)HCK有着互變異構,雖然該異構體不佔主導,但能夠和碘乙烷反應,產生該異構體的取代物:

(C6H5)(CN)HCK + C2H5I → (C6H5)(CN)HC(C2H5) + KI

腈的鎂、銅[6]、鋅鹽[7]也被製得,它們和鈉鹽一樣,都是很強的親核試劑。這些腈的金屬鹽中碳氮鍵的三鍵性質之外,通過X射線分析,還有部分碳碳雙鍵的性質。[8]

參考文獻

  1. ^ 1.0 1.1 Mary M. Rising, Tsoh-Wu Zee. SODIUM SALTS OF AROMATIC NITRILES. I. J. Am. Chem. Soc., 1928, 50 (6), pp 1699–1707. DOI: 10.1021/ja01393a028
  2. ^ 2.0 2.1 Robert West, Gerald A. Gornowicz. Polylithium compounds. IV. Polylithiation of nitriles and the preparations of trisilyl ynamines. J. Am. Chem. Soc., 1971, 93 (7), pp 1714–1720. DOI: 10.1021/ja00736a025
  3. ^ F. W. Bergstrom, Robert Agostinho. The Alkylation and Arylation of Aliphatic Nitriles in Liquid Ammonia. J. Am. Chem. Soc., 1945, 67 (12), pp 2152–2154. DOI: 10.1021/ja01228a025
  4. ^ Fred W. Upson, Robert T. Maxwell, Howard M. Parmelee. STRUCTURE OF THE SALTS OF AROMATIC NITRILES. J. Am. Chem. Soc., 1930, 52 (5), pp 1971–1975. DOI: 10.1021/ja01368a031
  5. ^ Mary M. Rising, Irving E. Muskat, Edmund W. Lowe. SALTS OF AROMATIC NITRILES. II. POTASSIUM PHENYLACETONITRILE. J. Am. Chem. Soc., 1929, 51 (1), pp 262–265. DOI: 10.1021/ja01376a033
  6. ^ Matthew Purzycki, Wang Liu, Göran Hilmersson, et al. Metalated nitriles: N- and C-coordination preferences of Li, Mg, and Cu cations. Chem. Commun., 2013,49, 4700-4702. DOI: 10.1039/C3CC41703D
  7. ^ Xun Yang, Dinesh Nath, and Fraser F. Fleming. Chemoselective Alkylations with N- and C-Metalated Nitriles. Org. Lett., 2015, 17 (19), pp 4906–4909 DOI: 10.1021/acs.orglett.5b02481
  8. ^ Fraser F. Fleming , Zhiyu Zhang , Wang Liu, et al. Metalated Nitriles: Organolithium, -magnesium, and -copper Exchange of α-Halonitriles. J. Org. Chem., 2005, 70 (6), pp 2200–2205. DOI: 10.1021/jo047877r
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腈鈉
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