Elimination of interference from water in KBr disk FT-IR spectra of solid biomaterials by chemometrics solved with kinetic modeling.

Infrared analysis of proteins and polysaccharides by the well known KBr disk technique is notoriously frustrated and defeated by absorbed water interference in the important amide and hydroxyl regions of spectra. This interference has too often been overlooked or ignored even when the resulting distortion is critical or even fatal, as in quantitative analyses of protein secondary structure, because the water has been impossible to measure or eliminate. Therefore, a new chemometric method was devised that corrects spectra of materials in KBr disks by mathematically eliminating the water interference. A new concept termed the Beer-Lambert law absorbance ratio (R-matrix) model was augmented with water concentration ratios computed via an exponential decay kinetic model of the water absorption process in KBr, which rendered the otherwise indeterminate system of linear equations determinate and thus possible to solve in a formal analytic manner. Consequently, the heretofore baffling KBr water elimination problem is now solved once and for all. Using the new formal solution, efforts to eliminate water interference from KBr disks in research will be defeated no longer. Resulting spectra of protein were much more accurate than attenuated total reflection (ATR) spectra corrected using the well-accepted Advanced ATR Correction Algorithm.

Osage Orange (Maclura pomifera L.) Seed Oil Poly(α-hydroxydibutylamine) Triglycerides: Synthesis and Characterization.

Milled Osage orange seeds (Maclura pomifera (Raf.) Schneid) were Soxhlet extracted with hexane, and portions of the extract were treated with activated carbon before solvent removal. The crude oil was winterized and degummed by centrifugation at low temperature. Decantation of the centrifugate gave an admixture of the triglycerides and free fatty acids. The free fatty acid content of the oil was removed when portions of the admixture were diluted with hexane and shaken with cold aqueous ammonium hydroxide (0.1 M) solution. The desiccant-dried organic phase was concentrated under reduced pressure to give the cleaned Osage orange triglyceride after solvent removal by rotary evaporation at 67 °C. Epoxidation of the resulting cleaned triglyceride was effected by reaction with in situ generated peroxy performic acid in H2O2. The oxirane rings of the derivatized oil were then opened using N,N-dibutylamine catalyzed by anhydrous ZnCl2 to afford the poly(α-hydroxydibutylamine) triglyceride. The purpose of this work was to derivatize and thereby stabilize this highly unsaturated tree oil for its eventual use in lubrication applications.

Syntheses of novel protein products (milkglyde, saliglyde, and soyglyde) from vegetable epoxy oils and gliadin.

The aqueous alcohol-soluble fraction of wheat gluten is gliadin. This component has been implicated as the causative principle in celiac disease, which is a physiological condition experienced by some infants and adults. The outcome of the ingestion of whole wheat products by susceptible individuals is malabsorption of nutrients resulting from loss of intestinal vili, the nutrient absorption regions of the digestive system. This leads to incessant diarrhea and weight loss in these individuals. Only recently has this health condition been properly recognized and accurately diagnosed in this country. The culprit gliadin is characterized by preponderant glutamine side-chain residues on the protein surface. Gliadin is commercially available as a wheat gluten extract, and in our search for new biobased and environmentally friendly products from renewable agricultural substrates, we have exploited the availability of the glutamine residues of gliadin as synthons to produce novel elastomeric nonfood products dubbed "milkglyde", "saliglyde", and soyglyde from milkweed, salicornia and soybean oils. The reaction is an amidolysis of the oxirane groups of derivatized milkweed, salicornia, and soybean oils under neat reaction conditions with the primary amide functionalties of glutamine to give the corresponding amidohyroxy gliadinyl triglycerides, respectively. The differential scanning calorimetry, thermogravimetric analyses, and rheological data from a study of these products indicate properties similar to those of synthetic rubber.

Investigation of some characteristics of polyhydroxy milkweed triglycerides and their acylated derivatives in relation to lubricity.

Most industrial lubricants are derived from nonrenewable petroleum-based sources. As useful as these lubricants are, their unintended consequences are the pollution of the Earth's environment as a result of the slow degradation of the spent materials. Native seed oils, on the other hand, are renewable and are also biodegradable in the environment, but these oils often suffer a drawback in having lower thermal stability and a shorter shelf life because of the intrinsic -C═C- unsaturation in their structures. This drawback can be overcome, yet the inherent biodegradative property retained, by appropriate derivatization of the oil. Pursuant to this, this study investigated derivatized polyhydroxy milkweed oil to assess its suitability as lubricant. The milkweed plant is a member of the Asclepiadaceae, a family with many genera including the common milkweeds, Asclepias syriaca L., Asclepias speciosa L., Asclepias tuberosa L., etc. The seeds of these species contain mainly C-18 triglycerides that are highly unsaturated, 92%. The olefinic character of this oil has been chemically modified by generating polyhydroxy triglycerides (HMWO) that show high viscosity and excellent moisturizing characteristics. In this work, HMWO have been chemically modified by esterifying their hydroxyl groups with acyl groups of various chain lengths (C2-C5). The results of investigation into the effect of the acyl derivatives' chemical structure on kinematic and dynamic viscosity, oxidation stability, cold-flow (pour point, cloud point) properties, coefficient of friction, wear, and elastohydrodynamic film thickness are discussed.

Synthesis of diethylamine-functionalized soybean oil.

Specialty chemicals based on renewable resources are desirable commodities due to their eco-friendly nature and "green" product characteristics. These chemicals can demonstrate physical and chemical properties comparable to those of conventional petroleum-based products. Suitably functionalized amines in the triacylglycerol structure can function as an antioxidant, as well as an antiwear/antifriction agent. In addition, the amphiphilic nature of seed oils makes them an excellent candidate as base fluid. The reaction of amine and epoxidized seed oils in the presence of a catalyst almost always leads to different intra/intermolecular cross-linked products. In most cases, the triacylglycerol structure is lost due to disruption of the ester linkage. Currently, there is no reported literature describing the aminolysis of vegetable oil without cross-linking. Here the epoxy group of the epoxidized soybean oil has been selectively reacted with amines to give amine-functionalized soybean oil. The optimization procedure involved various amines and catalysts for maximum aminolysis, without cross-linking and disruption of the ester linkage. Diethylamine and ZnCl2 were found to be the best. NMR, IR, and nitrogen analysis were used to characterize the products.