Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that te...Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that terrestrial vegetation record from long-chain n-alkanes matched well with previous studies in nearby cores,showing that more C_(4)plants developed during the Last Glacial Maximum(LGM)and C_(3)plants dominated in the interglacial period.However,these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain n-alkanols,which showed C_(3)plant expansion during the LGM.The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain n-alkanols in the oxygen-rich bottom water,resulting in poor preservation of terrestrial vegetation signals.On the other hand,the different advantages of functionalized n-alkanols and non-functional n-alkanes to record local and distal vegetation signals,respectively,may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water.Nevertheless,large variations on n-alkyl lipid compositions in C_(3)/C_(4)plants could play a part in modulating sedimentary long-chain n-alkanols and n-alkanes toward different vegetation signals,thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain n-alkanols.展开更多
The molecular volumes of dioxins,organic phosphorous compounds and n-alkanols were computed at the B3LYP/6-311G** level,and were then correlated with their toxicity.It was surprisingly found that there exists the so-c...The molecular volumes of dioxins,organic phosphorous compounds and n-alkanols were computed at the B3LYP/6-311G** level,and were then correlated with their toxicity.It was surprisingly found that there exists the so-called“critical volume of toxicity”(CVT)in each series of compound of the present study,i.e.the toxicity increases with increase of the molecular volume when less than CVT,while decreasing with increase of the molecular volume when lar-ger than CVT.The CVT for the three series of compounds is quite similar,ranging 0.309—0.320nm3.It was proposed that the ordinary linear solvation energy relationship (LSER) should be modified with respect to the new findings,and ac-cordingly the anaesthetic potency of partial fluorinated n-alkanols was predicted.展开更多
bInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Solubilities of tetraphenylarsonium tetraphenylborate (Ph 4AsB Ph 4) in water, methanol, ethanol, 1 propanol, 1 butanol, 1 pentanol,...bInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Solubilities of tetraphenylarsonium tetraphenylborate (Ph 4AsB Ph 4) in water, methanol, ethanol, 1 propanol, 1 butanol, 1 pentanol, 1 hexanol and 1 octanol at T =293.2, 298.2, 303.2 and 308.2 K have been determined by spectrophotometry. The standard transfer Gibbs energy ( Δ tr G 0 w→s ) and entropy ( Δ tr S 0 w→s ) of Ph 4AsBPh 4 from water to the n alkanols at temerature from 293.2 K to 308.2 K have been obtained. Furthermore, the contribution of microscopic interaction to the standard Gibbs energy of transfer for Ph 4AsBPh 4 was calculated and discussed. The results show that the effect of hydrophobic interaction of Ph 4AsBPh 4 on its transfer process is the most important factor. According to the thermodynamical principle, the transfer process of Ph 4AsBPh 4 from water to the n alkanols is the entropy dominanted.展开更多
基金The Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)under contract No.GML2019ZD0104the Science and Technology Program of Guangzhou,China under contract No.201804010264+3 种基金the Guangdong MEPP Fund under contract No.GDOE[2019]A41the National Natural Science Foundation of China under contract No.41706059the Fund of Institution of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences under contract No.ISEE2020YB05the State Key R&D Project under contract No.2016YFA0601104。
文摘Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that terrestrial vegetation record from long-chain n-alkanes matched well with previous studies in nearby cores,showing that more C_(4)plants developed during the Last Glacial Maximum(LGM)and C_(3)plants dominated in the interglacial period.However,these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain n-alkanols,which showed C_(3)plant expansion during the LGM.The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain n-alkanols in the oxygen-rich bottom water,resulting in poor preservation of terrestrial vegetation signals.On the other hand,the different advantages of functionalized n-alkanols and non-functional n-alkanes to record local and distal vegetation signals,respectively,may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water.Nevertheless,large variations on n-alkyl lipid compositions in C_(3)/C_(4)plants could play a part in modulating sedimentary long-chain n-alkanols and n-alkanes toward different vegetation signals,thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain n-alkanols.
文摘The molecular volumes of dioxins,organic phosphorous compounds and n-alkanols were computed at the B3LYP/6-311G** level,and were then correlated with their toxicity.It was surprisingly found that there exists the so-called“critical volume of toxicity”(CVT)in each series of compound of the present study,i.e.the toxicity increases with increase of the molecular volume when less than CVT,while decreasing with increase of the molecular volume when lar-ger than CVT.The CVT for the three series of compounds is quite similar,ranging 0.309—0.320nm3.It was proposed that the ordinary linear solvation energy relationship (LSER) should be modified with respect to the new findings,and ac-cordingly the anaesthetic potency of partial fluorinated n-alkanols was predicted.
文摘bInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Solubilities of tetraphenylarsonium tetraphenylborate (Ph 4AsB Ph 4) in water, methanol, ethanol, 1 propanol, 1 butanol, 1 pentanol, 1 hexanol and 1 octanol at T =293.2, 298.2, 303.2 and 308.2 K have been determined by spectrophotometry. The standard transfer Gibbs energy ( Δ tr G 0 w→s ) and entropy ( Δ tr S 0 w→s ) of Ph 4AsBPh 4 from water to the n alkanols at temerature from 293.2 K to 308.2 K have been obtained. Furthermore, the contribution of microscopic interaction to the standard Gibbs energy of transfer for Ph 4AsBPh 4 was calculated and discussed. The results show that the effect of hydrophobic interaction of Ph 4AsBPh 4 on its transfer process is the most important factor. According to the thermodynamical principle, the transfer process of Ph 4AsBPh 4 from water to the n alkanols is the entropy dominanted.
