PHYSICAL-PROPERTIES OF INSECT CUTICULAR HYDROCARBONS - THE EFFECTS OF CHAIN-LENGTH, METHYL-BRANCHING AND UNSATURATION
PHYSICAL-PROPERTIES OF INSECT CUTICULAR HYDROCARBONS - THE EFFECTS OF CHAIN-LENGTH, METHYL-BRANCHING AND UNSATURATION
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DOI：
10.1016/0305-0491(95)00081-x
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发表时间：
1995-10-01
影响因子：
2.2
通讯作者：
POMONIS, JG
中科院分区：
文献类型：
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作者：
GIBBS, A;POMONIS, JG
昆虫表皮脂质主要由碳氢化合物组成，其防水能力取决于其生物物理性质。然而，鲜为人知的是，关于特定的结构变化对表皮脂质性质的影响。我们研究了不同的链长，甲基支化模式，和不饱和度的纯烃的相行为，使用傅里叶变换红外光谱。21-40碳正构烷烃的熔融温度（Tm）随着一个碳原子的主链长度的增加而增加1-3 ℃。甲基支化对烃性质的影响取决于甲基在分子中的沿着位置。25-碳长的甲基二十五烷的熔融温度降低超过30摄氏度，因为甲基部分的位置从分子的末端部分移动到更内部的位置。添加第二个甲基分支对T-m有额外的影响。不饱和使Tm降低50 ℃或更多。
The waterproofing abilities of insect cuticular lipids, consisting mainly of hydrocarbons, are thought to depend upon their biophysical properties. However, little is known regarding the effects of specific structural changes upon cuticular lipid properties. We examined the phase behavior of pure hydrocarbons differing in chain length, methyl-branching pattern, and unsaturation, using Fourier transform infrared spectroscopy. Melting temperatures (T-m) of 21-40 carbon n-alkanes increased by 1-3 degrees C for an increase in backbone chain length of one carbon atom. The effects of methyl-branching on hydrocarbon properties depended upon the location of the methyl group along the molecule. Melting temperatures of 25-carbon long methylpentacosanes decreased by over 30 degrees C as the location of the methyl moiety was shifted from the terminal portion of the molecule to more internal positions. Addition of a second methyl branch had additional effects on T-m. Unsaturation decreased T-m by 50 degrees C or more.