Chemistry of lac resin-VIII

Singh, A.N.; Mhaskar, V.V.; Dev, Sukh

doi:10.1016/0040-4020(78)80058-1

Cited by 16 publications

(5 citation statements)

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“…The structure of the lac “molecule” is relatively complex, due to the presence of several constituents in physical and chemical combination. These constituents include aleuritic acid, shellolic acid, butolic acid, jalaric acid and their epimers (Wadia et al , 1969; Singh et al , 1969, 1978). Although the exact nature of this resin is not fully understood, lac is believed to have ester linkages, carboxylic acid groups, aldehydic groups, alcoholic moieties and points of unsaturation (Mishra and Sengupta, 1970; Sukh, 1974).…”

Section: Introductionmentioning

confidence: 99%

Study of thermal behaviour of lac resin using specular reflectance spectroscopy

Bhatia

Sarkar

Alam

2006

Pigment &Amp; Resin Technology

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PurposeTo determine molecular level changes occurring in lac resin, due to the effect of thermal stress at different levels of temperature and baking times.Design/methodology/approachFilms of lac resin were applied on tin panels and baked at 100 and 200°C for different time intervals. The baked films were examined by specular reflectance spectroscopy, as they were otherwise difficult to examine through conventional IR techniques, using KBr pellet method. The results obtained were compared and correlated with work reported by earlier authors using wet chemical methods.FindingsNo significant spectroscopic change was observed on heating lac resin films at 100°C for different time intervals, as compared to air‐dried (parent) lac films. However, it was observed that when the films were baked at 200°C, the spectroscopic data indicated anhydride formation in the oligomers, due to heating effects.Research limitations/implicationsChemical researches on lac resin have been typically limited by lack of modern tools, due to the difficult and unique nature of the material. The present method to determine molecular level changes in lac due to heating effects, using state‐of‐art instrumentation and computational technique opens a new vista in this field of research.Practical implicationsLac resin still has a significant place in the surface coating industry, typically in food applications, insulating vanishes, etc. The results obtained indicate that lac‐based baking compositions, when baked at 200°C, exhibit improved characteristics, in terms of adhesion, scratch hardness and even acid resistance. Such an improvement can be attributed unequivocally to the formation of anhydride linkage as evident from spectroscopic data.Originality/valueAs of now, there is no report of specular reflectance data on lac resin and its derivatives. This paper represents the first attempt to obtain and correlate reflectance data on lac. It also highlights the convenience of the method and the scope of sophisticated data analysis, using computational methods.

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Section: Introductionmentioning

confidence: 99%

Study of thermal behaviour of lac resin using specular reflectance spectroscopy

Bhatia

Sarkar

Alam

2006

Pigment &Amp; Resin Technology

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“…Commercial aleuritic acid 4 (Tridom-Fluka) could be converted to (E)-16-hydroxy-9-hexadecenoic acid (5), recrystallized from CC14, mp 64-66 °C (lit. mp 69-70 °C) (Singh et al, 1978).…”

Section: Resultsmentioning

confidence: 99%

“…mp. 125-126 °C)] and then bisdehydroxylation to the corresponding (Z)-9-hydroxy acid 12 (81%; oil) (Singh et al, 1978). The crude acid was esterified (81%), fluorinated and chromatographed (68%), and hydrolyzed (85%) as described above for the E-9 acid, giving the (Z)-9-fluoro acid 15 as a clear oil which solidified below 20 °C: IR 1978).…”

Section: Resultsmentioning

confidence: 99%

“…The 1-0hexadecyl group was employed to decrease acyl migration both in vivo and during synthetic procedures. The choice of the (E)-16-fluoro-9-hexadecenoic acid as the O-fluoroacyl moiety reflects (1) the ready availability of the corresponding 16-hydroxy acid in one step (Singh et al, 1978) from commercially available aleuritic acid {threo-9,10,16trihydroxyhexadecanoic acid), (2) the ability to monitor incorporation by NMR using the ratios of -CH2F, vinylic, and allylic protons to -CH20-and -C(=0)CH2protons, and (3) increased delay time for /3-oxidation of the unnatural (E) double bond.…”

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confidence: 99%

See 1 more Smart Citation

Synthesis of fluorolipids: 1-O-alkyl-2,3-O-diacyglycerols as targeted insecticides

Prestwich¹,

Plavcan²,

Melcer³

1981

J. Agric. Food Chem.

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“…(Scheme 1.). Thus, the acid 1 was first dihydroxylated [9] with HCO 3 H to the diol acid 2a. After esterification to 2b, the diol function was cleaved with NaIO 4 .…”

Section: Introductionmentioning

confidence: 99%