Matches in SemOpenAlex for { <https://semopenalex.org/work/W2056566861> ?p ?o ?g. }
Showing items 1 to 90 of
90
with 100 items per page.
- W2056566861 endingPage "1058" @default.
- W2056566861 startingPage "1056" @default.
- W2056566861 abstract "Nitration of aromatic compounds is one of the most widely studied organic reactions. Since the nitrated products are important intermediates for pharmaceuticals, perfumes, plastics and dyes; nitration of aromatic compounds is an industrially consequential reaction. Classical nitration method usually requires the use of an excess of nitric acid and the assistance of strong acids such as concentrated sulfuric acid. Usually nitration reactions are not selective and suffer from low regioselectivity and over nitration and are the cause of environmental concerns regarding the disposal of the large excess of mixed acids and generating nitrogen oxide (NOx) fumes and leading to excess acid waste and added expense. The problems associated with mixed nitric and sulfuric acids have prompted the research for alternative methods. In literature a number of different methods including concentrated nitric acid, solid acids, acid anhydrides or triflates, peroxy nitrite, metal nitrates, nitrogen oxides and organic nitrating agents have been utilized by many investigators. Some of them are based on homogeneous procedure in solution while others depend upon reactions involving heterogeneous conditions. In some cases the reaction has been performed in expensive media such as ionic liquids. Microwave assisted synthesis of unusual dinitro phytochemicals has also been studied recently. Nitration of phenols, among the aromatic compounds, also has been studied using various nitrating agents under different conditions. However, there is a great need for new nitration methods that can overcome the problems such as low yield , low selectivity and over nitration. Solvent free condition for organic synthesis has been of great interest in recent years. Elimination of volatile organic solvents in organic synthesis is the most important goal in green chemistry. Solvent free organic reactions make synthesis simpler, save energy and prevent solvent wastes hazards and toxicity. A new nitration process of phenols in the solid state has been the focus of the present work. Conversions of various phenolic compounds are shown in Table 1 and compared with previous results in solution. Different solid acids like, p-TsOH, mono and trichloro acetic acid and heteroplyacids were used that they either didn't work in the reaction condition or gave a very poor yield of nitrated products. We found that oxalic acid could be considered as the best solid acid for nitration of phenols in the solid state. In most of the abovementioned cases, complete conversion of the starting phenols was achieved under the reaction condition. As it can be seen in Table 1, complete conversion to mononitrophenols occurred by microwave irradiation for a few minutes (entries 4, 6, 7, 9, 10). The reaction was studied at different molar ratio of reagents. Except entries 6 and 8, in which the use of equimolar reagents to phenols caused a decrease in the regioselectivity together with the formation of some byproducts, the reaction was completed by the use of 1.2 to 1.4 eq. of reagents. Phenol was nitrated to mononitrophenols, and the ratio of ortho-nitrophenol : para-nitrophenol was found to be 4 : 6, also a very small amount of para-benzoquinone was detected. Parahydroquinone (entry 2) was oxidized to para-benzoquinone, exclusively. 2-Iodophenol and 3Chlorophenol were nitrated to mononitrophenols with the 1 : 4 ratio of ortho-nitrated : para-nitrated product. In conclusion, we have demonstrated that (CO2H)2/ NaNO3 is an extremely powerful and efficient nitrating agent for phenols under simple condition. Other development of this reagent in the solid state processes is in progress." @default.
- W2056566861 created "2016-06-24" @default.
- W2056566861 creator A5031526672 @default.
- W2056566861 creator A5035427493 @default.
- W2056566861 creator A5047220449 @default.
- W2056566861 creator A5084336315 @default.
- W2056566861 date "2006-01-20" @default.
- W2056566861 modified "2023-10-18" @default.
- W2056566861 title "Facile and Efficient Selective Mono-nitration of Phenols under Solvent-free Conditions" @default.
- W2056566861 cites W1971999365 @default.
- W2056566861 cites W1985172422 @default.
- W2056566861 cites W1988079982 @default.
- W2056566861 cites W1997139880 @default.
- W2056566861 cites W1999243298 @default.
- W2056566861 cites W2002076340 @default.
- W2056566861 cites W2003790724 @default.
- W2056566861 cites W2014209608 @default.
- W2056566861 cites W2021173097 @default.
- W2056566861 cites W2028206934 @default.
- W2056566861 cites W2030833038 @default.
- W2056566861 cites W2034301381 @default.
- W2056566861 cites W2048580445 @default.
- W2056566861 cites W2051890133 @default.
- W2056566861 cites W2059165495 @default.
- W2056566861 cites W2061880176 @default.
- W2056566861 cites W2065737062 @default.
- W2056566861 cites W2068663610 @default.
- W2056566861 cites W2083075421 @default.
- W2056566861 cites W2083756106 @default.
- W2056566861 cites W2092893079 @default.
- W2056566861 cites W2096700319 @default.
- W2056566861 cites W2105072493 @default.
- W2056566861 cites W2111292116 @default.
- W2056566861 cites W2120340355 @default.
- W2056566861 cites W2175092065 @default.
- W2056566861 cites W2176807744 @default.
- W2056566861 cites W2333061831 @default.
- W2056566861 cites W2950221692 @default.
- W2056566861 cites W2952079586 @default.
- W2056566861 cites W2952719033 @default.
- W2056566861 cites W2953190979 @default.
- W2056566861 cites W4249465994 @default.
- W2056566861 cites W1966762464 @default.
- W2056566861 doi "https://doi.org/10.5012/bkcs.2006.27.7.1056" @default.
- W2056566861 hasPublicationYear "2006" @default.
- W2056566861 type Work @default.
- W2056566861 sameAs 2056566861 @default.
- W2056566861 citedByCount "5" @default.
- W2056566861 countsByYear W20565668612012 @default.
- W2056566861 countsByYear W20565668612014 @default.
- W2056566861 countsByYear W20565668612023 @default.
- W2056566861 crossrefType "journal-article" @default.
- W2056566861 hasAuthorship W2056566861A5031526672 @default.
- W2056566861 hasAuthorship W2056566861A5035427493 @default.
- W2056566861 hasAuthorship W2056566861A5047220449 @default.
- W2056566861 hasAuthorship W2056566861A5084336315 @default.
- W2056566861 hasBestOaLocation W20565668611 @default.
- W2056566861 hasConcept C178790620 @default.
- W2056566861 hasConcept C185592680 @default.
- W2056566861 hasConcept C21951064 @default.
- W2056566861 hasConcept C2775856698 @default.
- W2056566861 hasConcept C2777728882 @default.
- W2056566861 hasConcept C2780471494 @default.
- W2056566861 hasConceptScore W2056566861C178790620 @default.
- W2056566861 hasConceptScore W2056566861C185592680 @default.
- W2056566861 hasConceptScore W2056566861C21951064 @default.
- W2056566861 hasConceptScore W2056566861C2775856698 @default.
- W2056566861 hasConceptScore W2056566861C2777728882 @default.
- W2056566861 hasConceptScore W2056566861C2780471494 @default.
- W2056566861 hasIssue "7" @default.
- W2056566861 hasLocation W20565668611 @default.
- W2056566861 hasOpenAccess W2056566861 @default.
- W2056566861 hasPrimaryLocation W20565668611 @default.
- W2056566861 hasRelatedWork W2024777516 @default.
- W2056566861 hasRelatedWork W2036536771 @default.
- W2056566861 hasRelatedWork W2041305652 @default.
- W2056566861 hasRelatedWork W2317452413 @default.
- W2056566861 hasRelatedWork W2319601796 @default.
- W2056566861 hasRelatedWork W2403580444 @default.
- W2056566861 hasRelatedWork W2951803252 @default.
- W2056566861 hasRelatedWork W2952186766 @default.
- W2056566861 hasRelatedWork W2952186923 @default.
- W2056566861 hasRelatedWork W4252524260 @default.
- W2056566861 hasVolume "27" @default.
- W2056566861 isParatext "false" @default.
- W2056566861 isRetracted "false" @default.
- W2056566861 magId "2056566861" @default.
- W2056566861 workType "article" @default.