Mineral aerosol particles significantly impact environmental risk prediction of liquid crystal monomers(LCMs).In this work,we investigated the reaction mechanisms and kinetics of three typical LCMs(4-cyano-3,5-difluor...Mineral aerosol particles significantly impact environmental risk prediction of liquid crystal monomers(LCMs).In this work,we investigated the reaction mechanisms and kinetics of three typical LCMs(4-cyano-3,5-difluorophenyl 4-ethylbenzoate(CEB-2F),4-cyano-3-fluorophenyl 4-ethylbenzoate(CEB-F),and 4-cyanophenyl 4-ethylbenzoate(CEB))with ozone(O_(3))in the atmospheric gas,liquid,and particle phases employing density functional theory(DFT).Here,O_(3)is prone to add to the benzene ring without F atom(s)in the selected LCMs.The ozonolysis products are aldehydes,carboxylic acids,epoxides,and unsaturated hydrocarbons containing aromatic rings.Those products undergo secondary ozonolysis to generate small molecular compounds such as glyoxal,which is beneficial for generating secondary organic aerosol(SOA).Titanium dioxide(TiO_(2)),an essential component of mineral aerosol particles,has good adsorption properties for LCMs;however,it slightly reduces the reactivity with O_(3).At 298 K,the reaction rate constant of the selected LCMs reacting with O_(3)in the gas and atmospheric liquid phases is(2.74–5.53)×10^(-24)cm^(3)/(mol·sec)and 5.58×10^(-3)–39.1 L/(mol·sec),while CEB-2F reacting with O_(3)on(TiO_(2))_(6)cluster is 1.84×10^(-24)cm^(3)/(mol·sec).The existence of TiO_(2)clusters increases the persistence and long-distance transportability of LCMs,which enlarges the contaminated area of LCMs.展开更多
A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the...A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.展开更多
Liquid crystal monomers(LCMs)are a family of synthetic organic chemicals applied in the liquid crystal displays(LCDs)of various electric and electronic products(e-products).Due to their unique properties(i.e.,persiste...Liquid crystal monomers(LCMs)are a family of synthetic organic chemicals applied in the liquid crystal displays(LCDs)of various electric and electronic products(e-products).Due to their unique properties(i.e.,persistence,bioaccumulative potential,and toxicity)and widespread environmental distributions,LCMs have attracted increasing attention across the world.Recent studies have focused on the source,distribution,fate,and toxicity of LCMs;however,a comprehensive review is scarce.Herein,we highlighted the persistence and bioaccumulation potential of LCMs by reviewing their physical–chemical properties.The naming rules were suggested to standardize the abbreviations regarding LCMs.The sources and occurrences of LCMs in different environmental compartments,including dust,sediment,soil,leachate,air and particulate,human serum,and biota samples,were reviewed.It is concluded that the LCMs in the environment mainly originate from the usage and disassembly of eproducts with LCDs.Moreover,the review of the potential recycling and removal technologies regarding LCMs from waste LCD panels suggests that a combination of natural attenuation and physic-chemical remediation should be developed for LCMs remediations in the future.By reviewing the health risks and toxicity of LCMs,it is found that a large gap exists in their toxicity and risk to organisms.The fate and toxicity investigation of LCMs,and further investigations on the effects on the human exposure risks of LCMs to residents,especially to occupational workers,should be considered in the future.展开更多
Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]b...Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]benzene(TPrCB),1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]benzene(DPrCB),4-[(trans,trans)-4'-(3-Buten-1-yl)[1,10-bicyclohexyl]-4-yl]-1,2-difluoro-benzene(BBDB)and 1-[4-(4-ethylcyclohexyl)cyclohexyl]-4(trifluoromethoxy)benzene(ECTB)subject to photocatalysis-generated oxidation species were investigated.The degradation rate constant of BBDB was 3.0,2.6,and 6.8 times higher than DPrCB,TPrCB and ECTB,respectively.The results reveal that BBDB,DPrCB and TPrCB had mainly negative electrostatic potential(ESP)regions which were vulnerable to electrophilic attack by h^(+),·OH and·O_(2)^(-),while ECTB was composed of mainly positive ESP regions which were vulnerable to nucleophilic attack by·OH and·O_(2)^(-).The detoxification processes of BBDB,DPrCB and TPrCB included carbon bond cleavage and benzene ring opening.However,the methoxy group of ECTB reduced the nucleophilic reactivity on the benzene ring,leading to slower detoxification efficiency.These findings may help to develop LCMs treatment technologies based on structure-reactivity relationships。展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.22276109,21777087,and 21876099)。
文摘Mineral aerosol particles significantly impact environmental risk prediction of liquid crystal monomers(LCMs).In this work,we investigated the reaction mechanisms and kinetics of three typical LCMs(4-cyano-3,5-difluorophenyl 4-ethylbenzoate(CEB-2F),4-cyano-3-fluorophenyl 4-ethylbenzoate(CEB-F),and 4-cyanophenyl 4-ethylbenzoate(CEB))with ozone(O_(3))in the atmospheric gas,liquid,and particle phases employing density functional theory(DFT).Here,O_(3)is prone to add to the benzene ring without F atom(s)in the selected LCMs.The ozonolysis products are aldehydes,carboxylic acids,epoxides,and unsaturated hydrocarbons containing aromatic rings.Those products undergo secondary ozonolysis to generate small molecular compounds such as glyoxal,which is beneficial for generating secondary organic aerosol(SOA).Titanium dioxide(TiO_(2)),an essential component of mineral aerosol particles,has good adsorption properties for LCMs;however,it slightly reduces the reactivity with O_(3).At 298 K,the reaction rate constant of the selected LCMs reacting with O_(3)in the gas and atmospheric liquid phases is(2.74–5.53)×10^(-24)cm^(3)/(mol·sec)and 5.58×10^(-3)–39.1 L/(mol·sec),while CEB-2F reacting with O_(3)on(TiO_(2))_(6)cluster is 1.84×10^(-24)cm^(3)/(mol·sec).The existence of TiO_(2)clusters increases the persistence and long-distance transportability of LCMs,which enlarges the contaminated area of LCMs.
文摘A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.
基金funded by the National Key Research and Development Project of China(2022YFC3703203)the National Natural Science Foundation of China(42207484)Ministry of Education of China(T2017002).
文摘Liquid crystal monomers(LCMs)are a family of synthetic organic chemicals applied in the liquid crystal displays(LCDs)of various electric and electronic products(e-products).Due to their unique properties(i.e.,persistence,bioaccumulative potential,and toxicity)and widespread environmental distributions,LCMs have attracted increasing attention across the world.Recent studies have focused on the source,distribution,fate,and toxicity of LCMs;however,a comprehensive review is scarce.Herein,we highlighted the persistence and bioaccumulation potential of LCMs by reviewing their physical–chemical properties.The naming rules were suggested to standardize the abbreviations regarding LCMs.The sources and occurrences of LCMs in different environmental compartments,including dust,sediment,soil,leachate,air and particulate,human serum,and biota samples,were reviewed.It is concluded that the LCMs in the environment mainly originate from the usage and disassembly of eproducts with LCDs.Moreover,the review of the potential recycling and removal technologies regarding LCMs from waste LCD panels suggests that a combination of natural attenuation and physic-chemical remediation should be developed for LCMs remediations in the future.By reviewing the health risks and toxicity of LCMs,it is found that a large gap exists in their toxicity and risk to organisms.The fate and toxicity investigation of LCMs,and further investigations on the effects on the human exposure risks of LCMs to residents,especially to occupational workers,should be considered in the future.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020038)the Pearl River Talent Recruitment Program of Guangdong Province(2019QN01L148)+3 种基金the National Natural Science Foundation of China(21876063 and 22076064)the Guangdong Special Support Program(2019TX05L129)the Guangdong(China)Innovative and Entrepreneurial Research Team Program(2016ZT06N258)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(2019B121205004).
文摘Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]benzene(TPrCB),1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]benzene(DPrCB),4-[(trans,trans)-4'-(3-Buten-1-yl)[1,10-bicyclohexyl]-4-yl]-1,2-difluoro-benzene(BBDB)and 1-[4-(4-ethylcyclohexyl)cyclohexyl]-4(trifluoromethoxy)benzene(ECTB)subject to photocatalysis-generated oxidation species were investigated.The degradation rate constant of BBDB was 3.0,2.6,and 6.8 times higher than DPrCB,TPrCB and ECTB,respectively.The results reveal that BBDB,DPrCB and TPrCB had mainly negative electrostatic potential(ESP)regions which were vulnerable to electrophilic attack by h^(+),·OH and·O_(2)^(-),while ECTB was composed of mainly positive ESP regions which were vulnerable to nucleophilic attack by·OH and·O_(2)^(-).The detoxification processes of BBDB,DPrCB and TPrCB included carbon bond cleavage and benzene ring opening.However,the methoxy group of ECTB reduced the nucleophilic reactivity on the benzene ring,leading to slower detoxification efficiency.These findings may help to develop LCMs treatment technologies based on structure-reactivity relationships。
