INDEX formate esters

The purest laevo-bornyl formate examined had a specific gravity 1 016, optical rotation — 48° 56, refractive index 1-47121, and boiling-point 97° at 15 mm. pressure. The ester has the constitution... 

Especial points which emerge from these studies include (a) the almost complete absence of reactivity of the hydroxy-groups of simple carbohydrates in water, which is attributed to their powerful solvation by water preventing a close approach of any other solute and (b) the ability of ester groups to interact with proton-acceptors. The refractive index tests, examination of m.p. or b.p., and infrared spectra of certain mono- and poly-esters appear to be interpreted most simply by assuming the formation of weak CH bonds by ester groups under the activating influence of the adjacent (5—0 double bond. These bonds can account for certain properties of l 2-diesters and for the adsorption of proton-acceptor solutes by cellulose acetates. 

Since both molar volume and refractive index are influenced by the actual molecular species present in a solution, molar refraction has some potential value for studying association equilibria. Giles and co-workers (65-68) correlated the method with dielectric constant measurements, and have been the most active users of refractive index for studying compound formation. Reference 68 reviews earlier work (which is sketchy) and lists about forty systems (mostly oxygen containing compounds) that were studied. References 65-67 deal with amide, amine, and azo compounds, plus esters and additional work on alcohols, aldehydes, ketones, and carbohydrates. The method is simple the refractive index of a series of mixtures of varying composition but constant concentration in a solvent is measured. Compound formation is shown by a change in the slope of the n vs. mole fraction plot, such as in Fig. 2-15. 

Effect of interaction of acid and cellulose at the stages of impregnation and thermal pretreatment depends on the cellulose properties. The celluloses under study have different ratios of ordered and amorphous regions. They differ also by their degree of polymerization (Table 1) and hydrophilic properties. The presence of phosphoric acid affects the system of the cellulose hydrogen bonds, the crystallinity index and leads to the formation of esters [11,12, 19],... 

The new approach has been termed The Mesogenic Index (MI) and has successfully been applied to 23 copolymer systems in which the critical compositions for mesophase formation have been established by means of varying constituent monomer concentrations. It is also consistent in predicting liquid crystalline behaviour in several hundred main-chain polymer systems containing amide, ester, carbonate, ether and urethane groups. 

Yellow prisms from propylene oxide or petr ether. Solvated crystals from more polar solvents, such as methanol or ethyl formate, mp 62-64°. Distills at 120-125" at 5 x lO-3 mm pressure, nj 1.6410 (calculated from refractive indexes of 20-70% solas in mineral oil), uv max 324-325 nm (E 1835) Baxter, Robeson, J. Am. Chem. Soc. 64, 2407 (1942+ Practically insol in water or glycerol sol in abs alcohol, methanol, chloroform, ether, fats and oils. Ultraviolet light inactivates vitamin A and its solns which exhibit a characteristic green fluorescence. The free alcohol is sensitive to air-oxidation, but oil solns of it are quite stable. Esters of vitamin A are more stable to oxidation. LDn (10 day) in mice (mg/kg) 1510 i.p. 2570 orally (Kamm). 

Continuous monitoring of density and refractive index for mixtures of trialkyl phosphites and the dihalides 20 indicates a two-stage interaction, the outcome of which, at room temperature, is the formation of the esters 21. No reaction occurs between 20 (X = Cl, Y = COOMe) and phosphite (R = Et or Bu), even at 60 but otherwise the products... 

CONTENTS Facial Diastereoselection in Diels-Alder Cycloadditions and Related Reactions Understanding Planar Interactions and Establishing Synthetic Potential, A. G. Faille and Yee-Fung Lu. Substituent and Structural Effects in the Ozonolysis of Cyclic Vinylogous Esters. W. H. Bunnelle. N-Metalated Azomethine Ylides, S. Kanemasa and Otohiko Tsuge. Azomethine Ylide Cy-cloadditlons via 1,2- Prototropy and Metallo-Dipole Formation from Imines, R. Grigg and V. Sridharan. Index. 

Synonyms Amyl formate Formic acid, isopentyl ester Isoamyl methanoate Isopentyl alcohol, formate Isopentyl formate 3-Methylbutyl formate 3-Methylbutyl methanoate Empirical C6H12O2 Formula HCOOCH2CH2CH(CH3)2 Properties Colorless liq., plum-like odor sol. in alcohol, oxygenated soivs. misc. with ether, propylene glycol very si. sol. in water insol. in glycerin m.w. 116.16 dens. 0.859 vapor pressure 10 mm (17.1 C) b.p. 123-124 C flash pt. 86 F ref. index 1.3960-1.40... 

Many cellulose derivatives form lyotropic liquid crystals in suitable solvents and several thermotropic cellulose derivatives have been reported (1-3) Cellulosic liquid crystalline systems reported prior to early 1982 have been tabulated (1). Since then, some new substituted cellulosic derivatives which form thermotropic cholesteric phases have been prepared (4), and much effort has been devoted to investigating the previously-reported systems. Anisotropic solutions of cellulose acetate and triacetate in tri-fluoroacetic acid have attracted the attention of several groups. Chiroptical properties (5,6), refractive index (7), phase boundaries (8), nuclear magnetic resonance spectra (9,10) and differential scanning calorimetry (11,12) have been reported for this system. However, trifluoroacetic acid causes degradation of cellulosic polymers this calls into question some of the physical measurements on these mesophases, because time is required for the mesophase solutions to achieve their equilibrium order. Mixtures of trifluoroacetic acid with chlorinated solvents have been employed to minimize this problem (13), and anisotropic solutions of cellulose acetate and triacetate in other solvents have been examined (14,15). The mesophase formed by (hydroxypropyl)cellulose (HPC) in water (16) is stable and easy to handle, and has thus attracted further attention (10,11,17-19), as has the thermotropic mesophase of HPC (20). Detailed studies of mesophase formation and chain rigidity for HPC in dimethyl acetamide (21) and for the benzoic acid ester of HPC in acetone and benzene (22) have been published. Anisotropic solutions of methylol cellulose in dimethyl sulfoxide (23) and of cellulose in dimethyl acetamide/ LiCl (24) were reported. Cellulose tricarbanilate in methyl ethyl ketone forms a liquid crystalline solution (25) with optical properties which are quite distinct from those of previously reported cholesteric cellulosic mesophases (26). 

---