http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
1P-632 Di-n-butyl carbonate synthesis form the direct carboxylation of n-Butanol by CO<sub>2</sub>
( Yeasin Khan ),김훈식 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
Synthesis of di-n-butyl carbonate was investigated from the reaction of n-butanol with carbon dioxide in presence of various catalysts and promoters. Effect of catalysts, reaction conditions and promoters were also investigated. Products and catalysts were characterized by GC, GC-MS, FTIR and XRD.
Selenite-catalyzed oxidative carbonylation of alcohols to dialkyl carbonates
Khan, Yeasin,Chung, Cheong Il,Oh, Jin Joo,Nguyen, Thanh Tung,Lee, Hye Jin,Cheong, Minserk,Walker, Bright,Kim, Hoon Sik,Kim, Yong Jin Elsevier 2019 Applied Catalysis B Vol.242 No.-
<P><B>Abstract</B></P> <P>The oxidative carbonylation of alcohols to prepare corresponding dialkyl carbonates was investigated using alkali metal methylselenite [MSeO<SUB>2</SUB>(OCH<SUB>3</SUB>)] and alkali metal selenites (M<SUB>2</SUB>SeO<SUB>3</SUB>, M = Li, Na, K, Cs) as catalysts. Of various alcohols tested, methanol and 2-methoxyethanol (MEG) are found to be highly reactive, affording corresponding dialkyl carbonates in yields of more than 30%, which are significantly higher than those achieved with Cu-based catalysts under similar reaction conditions. XRD and GC-Mass analysis of the spent catalyst recovered from the M<SUB>2</SUB>SeO<SUB>3</SUB>-catalyzed reaction of methanol revealed that M<SUB>2</SUB>SeO<SUB>3</SUB> was converted into elemental selenium and MHCO<SUB>3</SUB> along with the formation of several selenium-containing by-products including malodorous dimethyldiselenide, 1,2-dimethoxydiselane, and O,Se-dimethyl carbonoselenoate. On the contrary, the oxidative carbonylation of MEG with K<SUB>2</SUB>SeO<SUB>3</SUB> was highly selective toward the formation of bis(2-methoxyethyl) carbonate (BMEC), without producing any selenium-containing by-products. A plausible mechanism for the MSeO<SUB>2</SUB>(OCH<SUB>3</SUB>)- and M<SUB>2</SUB>SeO<SUB>3</SUB>-catalyzed oxidative carbonylation of MEG was suggested on the basis of mechanistic and experimental results.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Se-catalyzed oxidative carbonylation of alcohols to dialkyl carbonates (DACs). </LI> <LI> Alkali metal selenite (M<SUB>2</SUB>SeO<SUB>3</SUB>) was active for the carbonylation of alcohols to DACs. </LI> <LI> M<SUB>2</SUB>SeO<SUB>3</SUB> were transformed into Se and MHCO<SUB>3</SUB> during the carbonylation. </LI> <LI> K<SUB>2</SUB>SeO<SUB>3</SUB> was recyclable for the oxidative carbonylation of 2-methoxyethanol. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>K<SUB>2</SUB>SeO<SUB>3</SUB> was highly active, stable, and recyclable for the synthesis of bis(2-methoxyethyl) carbonate (BMEC) from the oxidative carbonylation of 2-methoxyethanol (MEG), but turned out to be unsuitable for the carbonylation of methanol, transforming into inactive and stinky selenium-containing compounds such as (CH<SUB>3</SUB>Se)<SUB>2</SUB>, CH<SUB>3</SUB>SeCO<SUB>2</SUB>CH<SUB>3</SUB>, and (CH<SUB>3</SUB>OSe)<SUB>2</SUB>.</P> <P>[DISPLAY OMISSION]</P>
Jin, So-Jeong,Khan, Yeasin,Maeng, Jee Hyun,Kim, Young Jin,Hwang, Junhyeok,Cheong, Minserk,Lee, Je Seung,Kim, Hoon Sik Elsevier BV 2017 Applied Catalysis B Vol.209 No.-
<P><B>Abstract</B></P> <P>The carboxylation of diamines to cyclic ureas by CO<SUB>2</SUB> in the presence of an alkali metal carbonate or alkali metal bicarbonate exhibits a typical autocatalysis behavior, in which the rates of corresponding cyclic urea formations increase with time as in a S-shaped curves. The activity of the alkali metal carbonate was greatly enhanced when ethylene urea was co-present. Computational calculation results on the carboxylation of ethylenediamine in the co-presence of KHCO<SUB>3</SUB> and ethylene urea suggest that ethylene urea of keto form could tautomerize into enol form with the aid of KHCO<SUB>3</SUB> at least to a certain extent, thereby playing a role as a proton donor. With such transformation and the consequent favorable hydrogen bonding interaction with KHCO<SUB>3</SUB>, the proton accepting and donating abilities of KHCO<SUB>3</SUB> can be enhanced and, as a result, the carboxylation is accelerated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of cyclic ureas by the carboxylation of diamines with CO<SUB>2</SUB>. </LI> <LI> Synergy effect of ethylene urea and a base in the carboxylation of diamines. </LI> <LI> Mechanistic and computational investigations on the active species. </LI> <LI> Effect of keto-enol tautomerization of ethylene urea on the activity of KHCO<SUB>3</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>