Crystalline complex between poly(γ-methyl l-glutamate) and dimethyl phthalate

The crystalline complex between poly(γ-methyl l-glutamate) (PMLG) and dimethyl phthalate (DMP) has been formed in films cast from a solution in dichloroethane. It has the stoichiometry of 1 mol of DMP to three or four residues of PMLG and shows two definite characteristics in X-ray diffraction patterns; one is the large hexagonal unit cell with the edge of around 28 Å and another the ‘extra’ 5.07 Å meridional reflection which can not be interpreted by a PMLG α-helical conformation. The structural examination for the films with various DMP contents is carried out by X-ray, viscoelastic, and d.s.c. measurements and the following structure is proposed for the crystalline complex. Four PMLG are associated to form a group which is hexagonally packed and DMP molecules, located in the gaps between groups, form a specific favourable helical structure along PMLG chains in which the van der Waals stacking of benzene rings of DMP is significant.     

Surfactants as replacements for natural lipids in bread baked from defatted wheat flour

Petroleum ether (PE) extracted 1.00% total free lipids (0.70% nonpolar and 0.30% polar) and 2-propanol (PrOH) extracted 1.36% total free and bound lipids (0.73% nonpolar and 0.63% polar) from wheat flour; the lipid fractions were characterized by thin layer chromatography. PE- or PrOH-defatted flours were baked after reconstitution with total, nonpolar, or polar wheat flour lipids; or with equivalent amounts of nonionic sucrose monopalmitate (SMP), ethoxylated monoglycerides (EMG) — each with a hydrophile-lipophile balance (HLB) of 14.0 or anionic sodium stearoyl-2-lactylate (SSL) — with an HLB value of 9.0. Defatted flours supplemented with surfactants alone or in combination with wheat flour lipids were used in bread with no-shortening and with 3%-shortening. The importance of the polar flour lipids in breadmaking was verified. The lipids in wheat flour were essential for maximizing the beneficial effects of shortening on breadmaking quality. Nonionic SMP or EMG completely replaced both PE-extractable wheat flour free total lipids ( or their non-polar or polar fractions) and 3% shortening; nonionic surfactants with high HLB were better than the anionic SSL for replacing free flour lipids. No surfactant completely replaced unfractionated PrOH-extracted lipids (free + bound) and shortening or total polar flour lipids (free + bound). All surfactants, especially anionic SSL, added with PrOH-extracted polar lipids improved the overall bread-making properties of the PrOH-defatted flour both in the absence and in the presence of shortening. Presented at the AOCS Meeting, New York, May 1977     

A generalized method for correcting instrument spreading in gel permeation chromatography

A general method of chromatogram correction for skewed instrument spreading in gel permeation chromatography is presented. The correction method is so general that there is no restriction on the shape of the spreading function. It admits nonsymmetric, non-Gaussian as well as nonconvolution type. Aspects of solution techniques are discussed and an illustrative example is given to elucidate the method.     

Synergistic Influence of Poly(4-Vinylpyridine) and Potassium Iodide on Inhibition of Corrosion of Mild Steel in 1M HCl

The corrosion and inhibition behavior of mild steel in 1 M HCl in the presence of poly(4-vinylpyridine)(P4VP) and potassium iodide (KI) was investigated using weight loss measurements, potentiodynamic polarization studies and impedance measurements. The inhibition efficiency increased with increasing P4VP concentration. The inhibiting action of P4VP is considerably enhanced by the addition of potassium iodide. The adsorption of this compound either alone or in combination with iodide ions on the metal surface is found to obey Lamgmir's adsorption isotherm. The experimental results suggest that the presence of iodide ions in the solution increases the surface coverage and, therefore, indicate the joint adsorption of P4VP and iodide ions. On the other hand, it was found that the inhibiting effect of P4VP and (P4VP + KI) increased with increasing temperature of the corrosion medium. The presence of these species in the solution decreases the double layer capacitance and increases the charge transfer resistance, both derived from Nyquist plots obtained from a.c. impedance studies. The variation of charge transfer resistance with time suggests that the inhibitive action of (P4VP + KI) depends mainly on the protective inhibitor film formed on the steel surface.     

Synthesis and characterization of poly(1,8-diethynylnaphthalene)

Summary The cyclopolymerization of 1,8-diethynylnaphthalene(DEN) and its copolymerization with diethyl dipropargylmalonate(DEDPM) were carried out by various transition metal catalysts. MoCl₅-based catalyst was found to be very effective and gave almost a quantitative polymer yield. The resulting dark-brown homopolymer(PDEN) was partially soluble in chloroform, tetrahydrofuran, and dimethyl sulfoxide, whereas copolymer (1:1) with number avaerage molecular weight of 2.1x10⁴ by GPC showed good solubility in those solvents. The structure of the polymers was analysed by IR, NMR, and UV-VIS spectroscopies. From the spectral and solubility data, it is proposed that cyclized products with the conjugated system are formed. Room temperature conductivities of the I₂-doped homo and copolymer were found to be about 7.5x10^-3 and 5.1x10^-3 S/cm, respectively.     

Anodic polarization of aluminium in organic electrolytes

The polarization characteristics of aluminium anodes have been studied in various organic electrolytes containing aluminium chloride. The small amount of oxide present on the metal was dissolved by an anodic pre-treatment. The charge transfer number of the overall reaction was three. The current density supported by the electrolytes decreased in the order nitromethane>acetonitrile >propylene carbonate, formamide>tetrahydrofuran. The rest potential increased in the order formamide     

Three-Chromophore Compounds I. Reductive Transformations of the 3,5-diaryl-2-cyclohexen-1-ones

The preparation of three 3,5-diarylcyclohexanones by rhodiumchlorotris(triphenyl-phosphine)—catalyzed reduction of the parent olefines (IIa—IIc) is described. Other reducing agents produced several intermediate products of the total hydrogenolysis.     

Bubble temperature data for phenol-alcohol systems: Phenol-I-Amyl alcohol and phenol-n-Amyl alcohol systems

In order to supplement the literature data on VLE, isobaric bubble temperature data were collected for the binary systems phenol-i-amyl alcohol and phenol-n-amyl alcohol over the entire composition range by indirect method using a standard Swietoslawski type ebulliometer. The measurements were made at three sub-atmospheric pressures. The experimental t-x data were correlated with both equation of state method and gamma-phi methods. In the former approach, the Soave equation of state is used, whereas in the latter case Wilson, NRTL and UNIQUAC equations are used.     

Evaluation of Trans and Essential Fatty Acid Content in Some Egyptian Consumer-Available Hydrogenated Fats

The fatty acid composition of cottonseed and com oils was determined before and after the technological hydrogenation process. In hydrogenated cottonseed and corn oils the essential fatty acid content (linoleic, 18:2 ω⁶) was decreased while the trans-18:1 acid was increased as compared to the native oils. The trans as well as the essential fatty acid contents in some consumeravailable hydrogenated fats were evaluated. The composition of cis and trans monoene isomers were also determined. This study revealed that some of the Egyptian consumer-available hydrogenated fats contain considerable amounts of trans acids.     

Influences of zinc oxide and an organic additive on the electrochemical behavior of pure aluminum in an alkaline solution

The corrosion behavior of pure aluminum in inhibited and uninhibited 4 MKOH was investigated by means of hydrogen collection, polarization curve measurement and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion of pure aluminum was greatly inhibited by the addition of ZnO and dimethyl amine epoxy propane (designated as DE). EIS and EDAX analyses revealed that ZnO produces its effect by depositing on the aluminum surface, which increases the overpotential of hydrogen evolution. It was also found that the addition of DE could greatly improve the deposition of zinc layers.