2-Hydroxy-3-napthoic acid

Pigment Red 144 [5280-784] 20735 disa2o condensation coupling of dia2oti2ed 2,5-dichloroaniline with 3-hydroxy-2-napthoic acid, foUowed by acid chloride formation and reaction with 2-chloro-/)-phen5iene- diamine... 

The ionic nature of these complexes is illustrated by the correlation of the stability of M(III), where M = Ce, Pr, Nd and Sm with hydroxy napthoic acids versus e2/r as shown in Fig. 3.5. 

Vectra A is a commercially available polymer from Hoechst-Celanese. It is a random co-polyester of hydroxy benzoic acid (HBA) and hydroxy napthoic acid (HNA), which is a well-known class of thermotropic liquid crystalline polymer (TLCP) [92-95]. Crystallization of molecules of TLCPs is considerably different from that of polymers like polyethylene or polyethylene terphthalate [1], TLCPs have reduced flexibility compared to the latter, which implies that large translations of their molecules are required for recrystallization [96-99],... 

Thermoset plastics having low permeability to fluids consisting of ethylene glycol, 4,4 -biphenol, terephthalic acid, 4-hydroxybenzoic acid, and 6-hydroxy-2-napthoic acid were prepared by Doshi et al. (4) and used in piping and containers with high fluid barrier limits. 

The indicator is 2-hydroxy-l-(2-hydroxy-4-sulpho-l-napthylazo)-3-napthoic acid commonly abbreviated as HHSNNA. Its main application is direct titration of calcium, particularly in presence of magnesium. A sharp colour change is from wine red to pure blue is obtained when calcium ions are titrated with EDTA at pH values between 12-14. 

Cyclisation of l-hydroxy-2-napthoic acid in dry toluene in the presence of phosphorous pentoxide as a dehydrating agent gives a small yield of a cyclic tetramer, termed tetra-l-napthoid (7.34). Host 7.34 forms a number of 1 2 clathrates with small molecules such as CHCI3 and benzene, which are very unstable with respect to desolvation. Complexes of 2-bromobutyric acid and napthalene are much more stable. A charge transfer complex with tetracyanoethylene (TCNE) is also known in which the electron-poor TCNE accepts electron density from the electron-rich aryl rings of the macrocycle. 

A typical semi rigid liquid crystal polymer which includes more than one mesogenic units are (a) Xydar which consists a copolyesters of 4, 4 -dihydroxybiphenol (BP), Phthalic acid (TA), and Hydroxy benzoic acid (HB A), (b) Vectra A950, a copolyesters of HBA and 2-Hydroxy-6-napthoic acid (HNA). Vectra B-950 is the only commercially available thermotropic LCPs containing amide linkages on the polymer main-chains. 

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