John A. Rothfus

DEVELOPMENT OF NEW CROPS FOR INDUSTRIAL RAW MATERIALS

Commercial fats and oils are still used extensively in chemical manufacturing processes, but their fatty acid compositions are limited in variety. An extensive screening program for potential new oilseed crops has led to the discovery of many good sources of new lipid classes and fatty acids. Among them are long-chain acids (Crambe, Limnanthes, Lunaria), medium-chain acids (Cuphea, Umbelliferae, Lauraceae), hydroxy acids (Lesquerella), epoxy acids (Vernonia, Stokesia), acids with special unsaturation (conjugated; acetylenic; Δ3, Δ5, Δ6, Δ17 monoenes) and liquid wax esters (Simmondsia). Many of these plant species have received further attention in terms of germplasm collection and evaluation; breeding and agronomic studies; and processing and utilization research on oil and byproduct meal. Some have been developed sufficiently for early commercialization. Recent history has shown this last step to be the most difficult. No satisfactory mechanism has been devised as yet to simplify the process of transferring research information on a developed new crop to reach the ultimate goal of sustained, large-scale commerical production. Close cooperation between governments and private sector institutions, with some financial support, may be required for the first few years to achieve successful commercialization.

Polymorphism and transformation energetics of saturated monoacid triglycerides from differential scanning calorimetry and theoretical modeling

Differential scanning calorimetry studies on saturated monoacid triglycerides were extended to include most odd and even chain lengths from tricaprylin (C8) through tritriacontanoin (C30). Two β’-forms were common with triglycerides C15 through C24: shorter odd chain length triglycerides (C9-C13) exhibited only one β’-form; short even chain length triglycerides (C8-C14) exhibited three. Odd chain length C21 and C23 triglycerides showed two β-forms. Triglycerides of even chain lengths greater than C21 produced two α-forms. Apparent energies of phase excitation for α-form transformations (determined from scans at different heating rates) showed odd-even alternation for short chain lengths, but increased linearly with chain length above C14, evidencing the importance of extended chain conformation and interactions as determinants of polymorph properties. Changes in melting point patterns, particularly for β’ and β-forms, at C14 correlated with the change in apparent phase excitation energy. Comparisons of X-ray data with dimensions from space-filling models and agreement between observed entropies of fusion and values calculated for probabilistic models also emphasize the importance of extended chain conformation and suggest configurational differences, and possibly different polymorph conversion pathways for odd versus even chain length triglycerides.

Antitumor alkaloids in callus cultures of Cephalotaxus harringtonia

Abstract Leaves and stems of Cephalotaxus harringtonia were induced to callus on Murashige and Skoog medium supplemented with additional vitamins, hypoxanthine, naphthaleneacetic acid and kinetin. Analysis by GC-MS showed cephalotaxine and its antitumor esters (harringtonine, isoharringtonine and homoharringtonine) in both callus and medium, whereas deoxyharringtonine was present (in relatively large amounts) only in the medium. The amount of each alkaloid was 2 to 6 times greater at 6 months than at 3 months except for deoxyharringtonine, which was not increased. At 6 months, the total alkaloid production was 1–3% of levels reported for mature trees, but the pattern was the same: 60% cephalotaxine, 40% esters. The pattern of the parent plant was unique (5% cephalotaxine, 80% homoharringtonine, 15% other esters) and may more accurately represent that of fresh plant material. A new cephalotaxine ester, homodeoxyharringtonine, was also detected in the culture medium.

Extreme—Pressure lubricant tests on jojoba and sperm whale oils

Laboratory and simulated in-use lubricant tests were performed on sulfurized jojoba oil and on reference sulfurized sperm whale oil. Data from these comprehensive tests indicated sulfurized jojoba oil prepared from heat-treated filtered oil to be comparable or superior to sulfurized sperm whale oil as an extreme-pressure additive for motor oils, gear lubricants, and automotive transmission fluids.

Computer modeling of theoretical structures of monoacid triglyceride α-forms in various subcell arrangements

Six theoretical triarachidin space-filling α-form structures were examined using a computer modeling technique that simulated restricted oscillations of carbon zigzag planes in synchronous and nonsynchronous modes. Intermolecular minimization procedures determined best-fit positions around a centralized molecule, which enabled calculation of total lattice energy values for nine different hexagonal subcell arrangements. Subcell arrangement had a greater effect on the energy of the system than did the configuration of the triglyceride. The analysis thus far indicates several equally preferred structure-sub cell arrangement combinations for triglyceride α-forms rather than a single crystalline entity.

Aminoethylation and fractionation of glutenin evidence of differences from gliadin

After reduction and aminoethylation, glutenin can be separated into four groups of proteins by fractional precipitation from 0.5 M acetic acid solution with Cu(NO3)2. Material precipitated by 0.0283 M Cu(NO3)2 accounts for 22% (w/w) of the glutenin and consists primarily of slow moving electrophoretic components. This fraction, which has an amino acid composition unlike other proteins from gluten, contains large amounts of glycine and tyrosine and low levels of histidine, methionine, valine and cysteine. The remaining fractions from glutenin resemble other gluten proteins more closely in composition. Gel permeation chromatography of the protein components from glutenin shows they have higher apparent molecular weights than gliadin.

Effects of chain length, conformation and α-form packing arrangement on theoretical monoacid triglyceride β′-forms

Theoretical β′-form monoacid triglycerides of odd and even chain length having a bend in the glycerol region were prepared by bond rotations from selected α-form conformers. The shapes of such β′-forms depend on the bonds rotated and the direction of rotation. Intermolecular minimization procedures determined best-fit positions around a centralized molecule, which revealed unsymmetrical packing among five of nine different energetically-favored orthorhombic subcell arrangements. Methyl gap energy is influenced more by overall triglyceride conformation than by whether the fatty acid chains have an odd or even number of carbon atoms. Total lattice-packing energies varied little between odd and even chain lengths; thus, many combinations of conformation and subcell arrangement are consistent with known X-ray long spacings and polymorphic behavior of β′-forms.

Oxidative stability of wax esters by thermogravimetric analysis

Relative oxidative stabilities of sperm whale oil and eight wax ester preparations were determined by comparing oxygen uptake profiles that had been corrected for ester volatility. Wax esters with unsaturation near the ester bond, even though more volatile, are as stable toward oxidation as those with double bonds near the center of each aliphatic chain.

Computer modeling for stabilities and structural relationships of n-hydrocarbons

Atom-atom spatial interactions were calculated for the four crystal packings known to exist in n-alkanes. Expression of end-group or mid-chain interactions as fractions of overall intermolecular interactions did not require use of the classical sixth power Lennard-Jones potential, yet allowed estimation of melting points within a given structural series and accurate prediction of the melting point of polyethylene. The calculations also provide a basis for explanation of structural relationships and stabilities among the four different n-paraffin forms.

Computer modeling ofα- toβ′- form phase transitions using theoretical triglyceride structures

Intermolecular energy calculations were performed on theoretical triarachidinα-form structures as selected bond rotations converted them intoβ′-forms with a chain-tilt change in the glycerol region. Interactions across the methyl gaps amounted to only 2-3% of the total energy in initialα- and finalβ′-forms, but computer generated energy profiles duringα- toβ′-phase transitions revealed highly repulsive regions due to the close approach of methyl groups. This methyl gap interaction, plus additional repulsive interactions in the lateral packing of molecules during rigid chain rotations, necessitated modification of certain chain movements during phase transition to reduce excessive repulsive energy. These results suggest that phase transitions proceed in a particular sequence of events that either distribute energy to promote further phase excitation or that lead to collapse into the stable polymorphic form. Phase transition energy curves also reveal that secondaryα- andβ′-forms are possible and are dependent on the startingα-forms, the direction of chain rotation and the subcell arrangement.