scholarly journals Relating side chain organization of PNIPAm with its conformation in aqueous methanol

Soft Matter ◽  
2016 ◽  
Vol 12 (38) ◽  
pp. 7995-8003 ◽  
Author(s):  
Debashish Mukherji ◽  
Manfred Wagner ◽  
Mark D. Watson ◽  
Svenja Winzen ◽  
Tiago E. de Oliveira ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Light Scattering ◽  
Magnetic Resonance ◽  
Dynamic Light Scattering ◽  
Side Chain ◽  
Aqueous Methanol ◽  
Chain Organization ◽  
Nuclear Magnetic

Combination of nuclear magnetic resonance, dynamic light scattering, and μs long all-atom simulations of 2 million particles reveal that the PNIPAm collapse in aqueous methanol mixtures is driven by enthalpy and the reopening at higher mole fractions of methanol is entropy driven.

Reaction of chloral with naphthalene, and the synthesis of α-methoxynaphthylacetic acids from naphthyl(trichloromethyl)carbinols

1968 ◽  
Vol 46 (13) ◽  
pp. 2233-2238 ◽  
Author(s):  
Wilkins Reeve ◽  
John C. Hoffsommer ◽  
Patrick F. Aluotto
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Side Chain ◽  
Naphthalene Ring ◽  
Ring Currents ◽  
Nuclear Magnetic

From the Friedel–Crafts reaction of chloral and naphthalene, others have reported the isolation of only 2-naphthyl(trichloromethyl)carbinol. Our reexamination of this reaction has shown that a mixture of 1- and 2-naphthyl(trichloromethyl)carbinols is obtained and that 80 to 90% of the product consists of the 1-naphthyl(trichloromethyl)carbinol. The 1- and 2-naphthyl(trichloromethyl)carbinols, their acetates, and their methyl ethers differ in their nuclear magnetic resonance (n.m.r.) spectra in that the signal of the α-hydrogen of the side chain of the 1-naphthyl isomer always occurs 0.8 p.p.m. downfield compared to the signal of the α-hydrogen of the corresponding 2-naphthyl isomer. This is because the α-hydrogens in the 1-naphthyl series of these compounds are in the region between the 1- and 8-positions of the naphthalene ring and subject to the ring currents of both benzenoid rings.The mixture of crude naphthyl(trichloromethyl)carbinols was converted to the mixture of α-methoxynaphthylacetic acids, and these were separated. A small amount of α,α′-dimethoxy-1,5-naphthalenediacetic acid was also obtained, demonstrating that a certain amount of 1,5-substitution occurred in the Friedel–Crafts reaction of naphthalene and chloral.

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