Refining method for crude cottonseed oil

Conclusion Acknowledgment is again given to Mr. Nelson W. Humbaugh who carried out the analytical work here recorded. A proposed revision of the refining method as at present written which is intended to embody all the points found desirable, is now in the hands of the members of the Refining Committee for consideration and test.     

Refining crude cottonseed oil dissolved in hexane

Measurements were made of the surface tensions of mixtures of cottonseed oil and hexane and of their interfacial tensions against water and caustic soda solutions. Attempts were made to study the reaction rate between the two phases. The results show that in caustic refining of hexane miscellas the caustic is readily dispersed into the oil-hexane phase. Refining losses were found to be lower for miscellas containing less than 70% oil. Concentrations as low as 40% were refined successfully. The losses were inversely related to the viscosity of the solution. Sponsored by the Texas Engineering Experiment Station and the Cotton Research Committee of Texas, College Station, Texas.     

Intrinsic viscosity of polymer solutions at high shear rates

Although low-shear intrinsic viscosity is a well-accepted tool for polymer characterization, it often happens (particularly with increasing molecular weights) that it is easier to detect the high-shear (second) Newtonian viscosity η₂ rather than its low shear counterpart. It has also been predicted that because of a higher degree of order, due to disentanglement and orientation, high-shear viscosity data should simplify the prevailing correlations. The possibility of using high-shear viscometric data for polymer characterization was examined by determining intrinsic viscosities for several polyisobutylene samples through extrapolation of the high-shear ultimate viscosity numbers, UVN, to zero concentration: [η]₂ = lim UVN_{C → 0} = lim_{C → 0} (η₂–η_s)/η_sC where η_s is the viscosity of the pure solvent. Five samples of unfractionated polyisobutylene (molecular weights of 1.1 × 10⁶–6.6 × 10⁶) in toluene, kerosene, decalin, and gas oil at concentrations of 0.05–2.4 g./dl. were studied. Higher dilution was avoided because of the problem of onset of turbulence. The absence of shear degradation was ascertained by measuring low-shear intrinsic viscosity data before and after the polymer was exposed to high-shear conditions. The data show two types of behavior: for the lower molecular weight samples in the low-viscosity solvents the UVN decreases linearly with dilution, and for the higher molecular weights and higher solvent viscosities the UVN increases with high dilution, i.e., shows an upturn effect. The first type of data can be successfully correlated with appropriate molecular weights by using a typical Mark-Houwink equation. The exponents in these relationships are in the range of 0.28–0.64, increasing systematically with decrease of solvent viscosity and independent of the “goodness” of the latter. The data that show an upturn effect are not currently amenable to reliable extrapolation techniques. The upturn, however, predicts the conformation of very flexible, isolated polymer chains in viscous solvents under conditions of high shear.     

Solvent hydrogenation of cottonseed oil

Refined and bleached cottonseed oil was dissolved in a solvent (hexane, isopropyl alcohol, or di-isopropyl ether) and was then hydrogenated in a dead-end hydrogenator. Hydrogenation runs were conducted at temperatures from 115 to 145°C., at hydrogen partial pressures from 44 to 74 p.s.i.a., with catalyst concentrations varying from 0.05 to 0.40% nickel, and at high rates of agitation to climinate mass-transfer resistances. A series of hydrogenation runs was also made in which no solvent was used. The rates of hydrogenation for the various series of runs were in the same order of magnitude but decreased in the following order: nonsolvent, hexane, isopropyl alcohol, and di-isopropyl other runs. Selectivity and isomerization were low in all cases and essentially identical for solvent and nonsolvent runs. The rate of hydrogenation increased in all cases with higher catalyst concentrations. For the isopropanol runs, the reaction rate was maximum as a function of temperature at about 135°C. In the case of the other solvents, the rate of hydrogenation increased with increased temperature in the range from 115 to 145°C., but the rate increases of the solvent runs were less than those of the nonsolvent runs.     

Constituents of crude cottonseed oil

Summary A small quantity of so-called vegetable mucilage was separated from crude cottonseed oil. It was precipitated from an aqueous solution by normal lead acetate. No water-soluble gum could be detected. Experiments showed that this mucilage readily emulsifies the oil with water and that the emulsion does not break after standing for several days. It is believed that the mucilage constitutes only a very small part of the non-glyceride substances present in the oil. Treating the oil with water and then extracting the separated oil repeatedly with large volumes of alcohol only removes part of the resin. The resin is partially removed from an alcoholic solution by an alcoholic solution of copper acetate in the form of a dark yellow flocculent precipitate. The copper salt is insoluble in alcohol and ether. It is believed that part of the deep red color of the crude oil is due to this resin. Presented at the 16th Annual Convention of The Am. Oil Chem. Soc’y, New Orleans, May, 1925.     

Constituents of crude cottonseed oil

Summary Crude cottonseed oil contains in addition to the constituents previously reported a lecithin type of phosphatide which gives an ether-soluble compound with cadmium chloride. This phosphatide can only be partially removed from the oil by extraction with alcohol. It has been found in the “settlings” from this oil. The treatment of the oil with water causes only a partial separation of this phosphatide. The phosphatides, resins, and presumably other substances present in small quantities in the crude oil have emulsifying properties and are undoubtedly the cause in part for the retention of oil in the soap stock when the oil is refined by caustic soda.     

Constituents of crude cottonseed oil

Summary The alcohol-soluble portion of the settlings which separate from clear crude cottonseed oil has been studied further. Although the oil had stood in the laboratory for about 3 years before the settlings were removed for the investigation, it was free from rancidity and in excellent condition. Palmitin, amounting to about 25 per cent, and di-palmitin, amounting to about 1 per cent of the total settlings, were isolated and identified. About 0.1 per cent of a phytosteroline, which gave an acetyl derivative melting at 166° to 167° C., was obtained. It appears from the results of this investigation that the dipalmitin, which was probably produced by the hydrolysis of a very small quantity of a tri-glyceride, accounts in part for the acetyl value obtained with cottonseed oil. As no investigation has succeeded in showing the presence of any hydroxy acids in cottonseed, or for that matter in many other oils giving a comparatively small acetyl value, the values noted may be largely due to the presence of small quantities of various di-glycerides.     

Carbon nanotubes prevent the coagulation at high shear rates of aqueous suspensions of equiaxed ceramic nanoparticles

Equiaxed ceramic nanoparticles and their mixtures are expected to exhibit shear-thinning behaviour when dispersed colloidally in aqueous media, whereas shear-thickening is the expectation for large aspect ratio phases such as, for example, carbon nanotubes (CNTs). Here, contrary experimental evidence is presented demonstrating the occurrence of severe coagulation at high shear rates in colloidally stable, semi-concentrated, aqueous suspensions of equiaxed SiC nanoparticles (major phase) mixed with equiaxed Y₃Al₅O₁₂ nanoparticles (liquid-phase sintering additive), and how CNT addition prevents this coagulation if sufficient sonication is applied. It is also shown that although shear-thinning is the natural behaviour of the ceramic suspension up to moderate shear rates, coagulation is eventually a phenomenon inherent to the aqueous colloidal processing of these suspensions, with the critical shear rate for coagulation increasing and the rheopexy decreasing the better is the initial dispersion state achieved with the sonication. It is also shown that the critical shear rate for coagulation depends on the exact condition of shear rate increase, and that the re-sheared suspensions coagulate more significantly and at lower shear rates than the fresh suspensions. The mechanisms by which this coagulation occurs and is impeded by the CNTs are discussed, together with broader implications of these phenomena for the environmentally friendly processing of nanostructured ceramics and ceramic composites.     

Diffusivities of hydrogen and glyceryl trioleate in cottonseed oil at elevated temperature

The diffusivities of hydrogen and glyceryl trioleate in cottonseed oil were determined at different iodine values. The diffusivity of hydrogen was shown to be ca. 100 times as great as that of the glyceryl trioleate. The diffusivities were shown to be dependent upon the iodine values. This influence could be explained, at least in the case of the glyceryl trioleate diffusion, by the difference of the viscosity of the oil. A separate determination of the solubility of hydrogen in the oil was a necessary part of the diffusivity determination.     

Color stability of glandless cottonseed oil

The color stability of oil extracted from glandless cottonseed contaminated with various levels of glanded cottonseed was studied. The rate of darkening in bleached color of cottonseed oil during storage was proportional to the original glanded cottonseed or gossypol content in the oil and to time and temperature of storage. Glandless cottonseed with 0–10% glanded seed contamination, as might be expected in commercial production of glandless cotton, yielded oil with equivalent or better color when conventionally refined and bleached after 30 days storage at 25 to 40 C than miscella refined oil from glanded cottonseed. This indicates that new oil mills for extracting glandless cottonseed need not invest in miscella-refining units in order to produce high quality oil.