IL Content Research Articles

Significantly enhancing enzymatic hydrolysis of rice straw after pretreatment using renewable ionic liquid–water mixtures

Pretreatment of rice straw by using renewable cholinium lysine ionic liquid ([Ch][Lys] IL)-water mixtures and subsequent enzymatic hydrolysis of the residues were conducted in this work. There is a clear correlation between the delignification capacity of the pretreatment solvent and its basicity. After pretreatment, surface area and pore volume of rice straw increased significantly, which substantially improved polysaccharides accessibility to enzymes and thus enhanced polysaccharides digestion. By carefully controlling the pretreatment severity (IL content, temperature and duration), loss of readily extractable xylan could be minimized. The sugar yields of 81% for glucose and 48% for xylose were achieved in the enzymatic hydrolysis of rice straw after pretreatment with 20% [Ch][Lys]-water mixture at 90°C for 1h. This pretreatment process is highly promising for industrial application because of high sugar yields, low energy input, short pretreatment time, and being environmentally benign and highly tolerant to moisture.

Gas transport properties and pervaporation performance of fluoropolymer gel membranes based on pure and mixed ionic liquids

Ionic liquid polymer gel membranes based on poly(vinylidene fluoride-co-hexafluoropropylene) (p(VDF-HFP)) were prepared by solvent casting from a solution in acetone. The membranes contain from 20wt% to 80wt% of pure or mixed ionic liquids based on the imidazolium cation: 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) and 1-hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HdMIM][TFSI]). Both ionic liquids have the fluorinated anion bis(trifluoromethylsulfonyl)imide, which should make them more compatible with a fluoropolymer matrix, while the different tail lengths in the cation give significantly different melting points. The thermal and mechanical properties of the blend membranes were evaluated and compared with the neat polymer. The performance of the membranes was tested in terms of pure gas permeability and selectivity, separation of limonene/carvone mixtures by pervaporation, and influence of a low water content in the feed on separation by the blended membrane.DSC analysis shows a gradual decrease of the melting point of the gel and a decrease in the overall melting enthalpy with increasing IL content, whereas the melting enthalpy normalized for the polymer fraction shows an initial drop and then a gradual increase. In the presence of the ionic liquid, the elastic modulus and break strength decrease dramatically, while the maximum deformation at first increases due to higher flexibility of the plasticized polymer and then rapidly decreases above 40wt% of IL as a consequence of the progressive decrease of the number of entanglements.The gas transport through the membranes prepared in this study was evaluated in the temperature range of 20–60°C, which includes the melting point of the high temperature ionic liquid [HdMIM][TFSI]. These permeation measurements show a significant increase of the permeability in the presence of the IL mixture, especially for carbon dioxide. This suggests a potential application in gas separation membranes, for instance for natural gas treatment or for CO2 sequestration from flue gas.

Synthesis and Characterization of Ionic Polymer Networks in a Room-Temperature Ionic Liquid

Ionic liquid gels (ILGs) for potential use in ion transport and separation applications were generated via a free radical copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and N,N'-methylene(bis)acrylamide (MBA) using 1-ethyl-3-methylimidazolium ethylsulfate (IL) as a room temperature ionic liquid solvent medium. The AMPS and MBA monomer solubility window in the IL in the temperature range of 25 to 65 °C was determined. In situ ATR-FTIR showed near complete conversion of monomers to a cross-linked polymer network. ILGs with glass transition temperatures (T(g)s) near -50 °C were generated with T(g) decreasing with increasing IL content. The elastic moduli in compression (200 to 6600 kPa) decreased with increasing IL content and increasing AMPS content while the conductivities (0.35 to 2.14 mS cm⁻¹) increased with increasing IL content and decreasing MBA content. The polymer-IL interaction parameter (χ) (0.48 to 0.55) was determined via a modified version of the Bray and Merrill equation.

Oil, Fatty Acid Profile and Karanjin Content in Developing Pongamia pinnata (L.) Pierre Seeds

AbstractOil content, fatty acid composition and karanjin content were studied in developing pongamia seeds, at intervals of 3 weeks from 30 weeks after flowering up to 42 weeks. Three marked stages in seed development were observed at the early green pod stage, the middle half brown stage and the late dark brown stage. Significant variation in seed biomass, pod and seed characteristics were observed. A significant (P < 0.01) decrease in the moisture content of the seeds was observed during seed development. The oil content gradually increased from 32.06 to 36.53 % as the seed matured. A significant variation in fatty acid composition was detected across all stages of seed development. Palmitic acid (16:0) content marginally decreased from 11.81 to 10.18 %, while stearic acid (18:0) and linolenic acid (18:3) remained constant at all stages of seed maturity. A steady increase in oleic acid (18:1) content from 38.11 to 49.11 % was observed, while the linoleic acid (18:2) content decreased from 30.14 to 18.85 %. The iodine value increased, while the saponification number of oil decreased during seed development. The increase in karanjin content was steady. Seeds harvested after 42 week after flowering yielded the maximum oil with high oleic acid content which could be suitable for biodiesel production.

Self-Assembly Behavior of N-Methly-N-Hexadecyl-Pyrrolidinium Bromide in Water

N-methyl-N-hexadecylpyrrolidinium bromide (IL) was synthesized for the design of ionic liquid crystals which is a fascinating class of molecular materials, offering the combination of order and mobility. In binary mixtures with water, lyotropic liquid crystalline phase appears in the range of IL content from 35% to 70% and the temperature range from -1.1 to 24 °C in the heating run. The SAXS curves explored the self-assembly processes and hexagonal phase of the IL apparent sol. The saturated aliphatic ionic liquid in water assemble less tightly compared with aromatic ionic liquid based on imidazolium in water, which is due to the absence of aromatic package effect.

High ionic liquid content polymeric gel membranes: Correlation of membrane structure with gas and vapour transport properties

Abstract In this paper the transport properties of ionic liquid polymeric gel membranes, containing up to 80 wt.% of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) in poly(vinylidene fluoride-co-hexafluoropropylene) (p(VDF-HFP)), are investigated. Gas permeability significantly increases in the presence of [EMIM][TFSI], especially for CO 2 . This suggests a potential application in gas separation membranes, for instance for natural gas sweetening and for CO 2 sequestration from flue gas. A correlation of the transport properties with Young's modulus is proposed for the first time. It reveals a transition from diffusion-controlled transport to solubility-controlled transport with increasing IL content in the membrane. Vapour permeation experiments with the most permeable membrane containing 80 wt.% of ionic liquid were carried out. Permeability, diffusion and solubility coefficients were correlated with molecular kinetic diameter or critical temperature and volume, respectively. These correlations show clear and distinct trends for water, alcohols, linear and cyclic hydrocarbons. Polar compounds (linear C 1 –C 4 alcohols, water) are more permeable and more sorbing than the corresponding hydrocarbons. The two classes show the opposite trends in permeability as a function of the critical volume, with an increase for the alkanes and a decrease for the alcohols. The same trends are observed for the solubility as a function of the critical temperature, evidencing that at such high IL concentrations in the membrane the mass transport is solubility controlled. On the other hand, diffusion is mainly correlated with the critical volume and the molecular size, regardless the chemical nature of the permeants. Significant differences in the transport of toluene and cyclohexane suggest that these membranes are also suitable for the separation of alkanes and aromatics. The manuscript intends to give fundamental information on how the presence of IL influences the transport properties of polymeric membranes.

Gas transport properties of Pebax®/room temperature ionic liquid gel membranes

This work evaluates the possibility to tailor the gas separation properties of elastomeric block co-polyamide membranes by means of room temperature ionic liquid (RTIL), based on the 1-n-alkyl-3-methylimidazolium cation. Polymeric gel membranes were prepared by adding from 20 to 80wt.% of 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMIM][CF3SO3] to Pebax®1657 and Pebax®2533.The effect of the ionic liquid on the microstructure, properties and performance of these membranes was discussed.DSC analysis showed a gradual decrease of the melting point of the polyamide (PA) blocks in the gel with a decrease in the corresponding melting enthalpy and a complete disappearance of the crystallinity of the polyether (PE) phase with increasing IL content in the case of Pebax®1657. In Pebax®2533 there is virtually no shift in the peak positions and both crystal phases remain present in the gel, indicating effective phase separation between the crystalline fraction of the polymer and the IL, in contrast with the high compatibility and the good mixing of the polymer and the IL observed in Pebax®1657.In the presence of the ionic liquid, the elastic modulus, break strength and maximum elongation all decrease monotonously for Pebax®2533. For the stiffer Pebax®1657 the break strength and maximum elongation show a maximum at low ionic liquid content and then rapidly decrease at higher IL concentration due to compromise between the plasticizing effect of the IL, enhancing its ductability, and the progressive weakening of the gel due to a reduction of the crystal fraction responsible for the mechanical strength.Gas permeation measurements show that the permeability and selectivity of Pebax®2533 are not notably affected by the addition of IL, whereas Pebax®1657 shows a significant increase in the gas permeability. At the same time the permselectivity of the latter for most gas pairs shows a slight decrease, in accordance with the typical Robeson trade-off behaviour. The combination of permeability and selectivity remains nevertheless interesting for applications involving for instance CO2 removal from exhaust gases.

Estimation of Oil Content and Fatty Acid Composition in Cottonseed Kernel Powder Using Near Infrared Reflectance Spectroscopy

AbstractOil content and fatty acid composition in 444 ground cottonseed kernel samples were analyzed using near infrared reflectance spectroscopy (NIRS). Calibration equations were developed for oil and fatty acid contents with the modified partial least squares (MPLS) regression method. The correlations between NIRS and reference values in external validation were in agreement with the predictions in calibration. Each equation was assessed based on the relative prediction determinant for external validation (RPDv). Equations corresponding to total oil content (RPDv = 11.495) and linoleic acid (RPDv = 5.026) showed high accuracy. For palmitic acid (RPDv = 1.914), myristic acid (RPDv = 1.724) and oleic acid (RPDv = 1.999), the equations were predicted with relatively high accuracy while those for palmitoleic acid (RPDv = 0.686), stearic acid (RPDv = 0.792), linolenic acid (RPDv = 0.475) and 1‐eicosenoic acid (RPDv = 0.619) were poorly predicted. The equations for traits with RPDv > 1.5 could be reliably used in screening samples for breeding programs.

Vesicles in Ionic Liquids

The formation of vesicles from 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) in several room-temperature ionic liquids, namely, 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF(4)), 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf(2)), and N-benzylpyridinium bis(trifluoromethylsulfonyl)imide (BnPyNTf(2)), as well as in a water/BmimBF(4) mixture, was investigated. In pure ionic liquids, observations by staining transmission electron microscopy demonstrated clearly the formation of spherical structures with diameters of 200-400 nm. The morphological characteristics of these vesicles in ionic liquids, in particular, the membrane thicknesses, were first investigated by small-angle neutron scattering measurements. The mean bilayer thickness was found to be ∼63 ± 1 Å in a deuterated ionic liquid (BnPyNTf(2)-d). This value was similar to that observed in water. The effect of ILs on the modification of the phase physical properties of multilamellar vesicles (MLVs) was then investigated by differential scanning calorimetry. In pure IL as in water, DPPC exhibited an endothermic pretransition followed by the main transition. These transition temperatures and the associated enthalpies in ILs were higher than those in water because of a reduction of the electrostatic repulsion between zwitterionic head groups. To better understand the effect of ionic liquid on the formation of multilamellar vesicles, mixtures of BmimBF(4) and water, which are miscible in all proportions, were analyzed (BmimBF(4)/water ratio from 0% to 100%). SANS and DSC experiments demonstrated that the bilayer structure and stability were strongly modified by the IL content. Moreover, matching SANS experiments showed that BmimBF(4) molecules prefer to be located inside the DPPC membrane rather than in water.

Ionic liquid crystalline phases in 3-hexadecylimidazolium bromide and binary mixtures with 1-decanol

3-Hexadecylimidazolium bromide was synthesized and characterized showing formation of thermotropic smectic liquid crystals at temperatures above its melting point from 48.5 to 150.9 °C. With decreasing temperature, the peak intensities in XRD patterns increase and full widths at half-maximum decrease, suggesting structural order increases with decreasing temperature. Compared with 1,2-dimethyl-3-hexadecyl-imidazolium bromide and hexafluorophosphate, the IL shows a lower melting point and less degree of chain interdigitation. The main reason is due to a more symmetrical structure and denser assembly of the IL molecules, which results in more steric resistance for the alkyl chain to interdigitate. The self-assembly behavior of the hydrophobic IL in an organic solvent was investigated showing SmA 2 lyotropic liquid crystalline phases. The first-order scattering peak shifts to lower q values with increasing IL content, which is opposite to the shift directions of the binary mixtures of the soluble imidazolium IL and water, indicating a different packing behavior of the hydrophobic IL in 1-decanol.

“Dry ionic liquid” as a newcomer to “dry matter”

Dry water (DW) is a kind of Pickering emulsion, where air serves as the nonpolar continuous phase in place of common organic solvents. Dry gel (DG) has also been prepared, which is superior to DW as a promising material for recyclable gas storage or gas separation. Here we add a new member, dry ionic liquid (D-IL), to those two kinds of ‘‘dry matter’’. Because of the non-volatility, D-IL is free from the fatal defect of DW and DG, i.e., collapse due to the temporal water vaporization in an open system. The chemical inertness of D-IL also provides potential applications for green chemistry, e.g., an organic solvent-free micro reaction vessel. In this study we report the first successful preparation of D-IL and discuss the preparation conditions such as properties of IL, IL/silica composition and water content.

High Ionic Liquid Content Polymeric Gel Membranes: Preparation and Performance

Ionic liquid polymeric gel membranes containing from 20 wt % to 80 wt % of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) in poly(vinylidene fluoride-co-hexafluoropropylene) (p(VDF-HFP)) were prepared by solvent casting from a solution in acetone. The effect of the ionic liquid on the performance and properties of the membranes was discussed and compared with the neat polymer. In the presence of an excess of ionic liquid, p(VDF-HFP) membranes swell in a significant way, especially above 70 °C, becoming completely soluble above 90 °C. DSC analysis shows a gradual decrease of the melting point of the gel and a decrease in the overall melting enthalpy with increasing IL content, whereas the melting enthalpy normalized for the polymer fraction shows an initial drop and then a gradual increase. In the presence of the ionic liquid, the elastic modulus and break strength decrease dramatically, while the maximum deformation first increases due to higher flexibility of the plasticized polymer and then rapidly decreases above 40 wt % of IL as a consequence of the progressive decrease of the number of entanglements. X-ray studies demonstrate a reduction in the overall crystal content. The position of the strongest diffraction peak remains unaltered in all samples, suggesting that only the polymer chains crystallize and that no cocrystallization of ionic liquid and polymer takes place. Preliminary gas permeation measurements show a significant increase of the permeability in the presence of [EMIM][TFSI], especially for carbon dioxide. This suggests a potential application in gas separation membranes, for instance for natural gas treatment or for CO2 sequestration from flue gas.

Room temperature ionic liquids as templates in the synthesis of mesoporous silica via a sol–gel method

With various RTILs as templates, amorphous mesoporous silica gel materials were synthesized according to a proper sol–gel method. The materials display pore diameter of 3–12 nm, pore volume of 0.4–1.3 cm 3/g and BET surface area of 300–800 m 2/g. The effect of variations of the anions and cations of ILs, the alkyl chain length on imidazolium cation and IL concentration in the reaction system on the pore structure and thermal stability of the silica gel materials was preliminarily studied. It is suggested that, the pore size of silica gel can be tuned by variations of ILs and IL content. The different kind of the anions of ILs could largely impact the properties of the obtained silica gel materials. The mesoporous silica gels with 1-alkyl-3-methylimidazolium tetrafluoroborate as templates possessed larger pore sizes of 5–12 nm and higher thermal stability than the materials obtained with other ILs as templates.

Bismuth recovery from acidic solutions using Cyphos IL-101 immobilized in a composite biopolymer matrix

Impregnated resins prepared by the immobilization of an ionic liquid (IL, Cyphos IL-101, tetradecyl(trihexyl)phosphonium chloride) into a composite biopolymer matrix (made of gelatin and alginate) have been tested for recovery of Bi(III) from acidic solutions. The concentration of HCl slightly influenced Bi(III) sorption capacity. Bismuth(III) sorption capacity increased with IL content in the resin but non-linearly. Maximum sorption capacity reached 110–130 mg Bi g −1 in 1 M HCl solutions. The mechanism involved in Bi recovery was probably an ion exchange mechanism, though it was not possible to establish the stoichiometric exchange ratio between BiCl 4 − and IL. Sorption kinetics were investigated through the evaluation of a series of parameters: metal concentration, sorbent dosage, type and size of sorbent particles and agitation speed. In order to reinforce the stability of the resin particles, the IL-encapsulated gels were dried; this may cause a reduction in the porosity of the resin particle and then diffusion limitations. The intraparticle diffusion coefficients were evaluated using the Crank's equation. Additionally, the pseudo-first-order and pseudo-second-order equations were systematically tested on sorption kinetics. Metal can be desorbed from loaded resins using either citric acid or KI/HCl solutions. The sorbent could be recycled for at least three sorption/desorption cycles.

Pt recovery using Cyphos IL-101 immobilized in biopolymer capsules

Cyphos ® IL-101, a tetraalkylphosphonium chloride salt (ionic liquid, IL) has been immobilized in capsules prepared by ionotropic gelation in calcium chloride solutions. The IL content was varied in the resin between 0.29 and 1.28 mmol IL g −1. These resins have been tested for Pt recovery from HCl solutions. The equilibrium was very slightly affected by the concentration of HCl and chloride ions. The sorption isotherms were modeled using the Langmuir equation: the maximum sorption capacity was influenced by the drying of the resin but remained close to 177 mg Pt g −1 for wet resin (i.e. 0.9 mmol Pt g −1, dry weight basis, or 0.7 mol Pt mol −1 Cyphos) and 142 mg Pt g −1 for dry resin (i.e. 0.73 mmol Pt g −1, or 0.57 mol Pt mol −1 Cyphos). The presence of nitrates, nickel or copper ions (added under the form of chloride salts) did not significantly decrease sorption capacity even at concentrations as high as 5 g L −1. Conversely, zinc at the concentration of 5 g L −1, significantly decreased Pt sorption, probably due to the competition effect of chloro-anionic Zn species. This is another evidence of the ion exchange mechanism involved in the binding of hexachloroplatinate species. The kinetics are weakly affected by the agitation speed (in the range 150–350 rpm) indicating that the resistance to film diffusion is not the limiting step. The kinetics are affected by the IL content, metal concentration and more specifically the drying of the resin: intraparticle diffusion sounds to be the controlling kinetic step: the intraparticle diffusion coefficient varied between 2 × 10 −12 and 18 × 10 −11 m 2 min −1, depending on experimental conditions. Platinum can be desorbed from loaded resin using either nitric acid (5 M) or thiourea (0.1 M in 0.1 M HCl acid solution). The resin was efficiently used for three sorption/desorption cycles using nitric acid: a decrease in sorption capacity and desorption efficiency was observed beginning with the third cycle, probably due to a progressive degradation of the resin.

Enhancing the activity and regioselectivity of lipases for 3′-benzoylation of floxuridine and its analogs by using ionic liquid-containing systems

Ionic liquid-containing systems offered new opportunities to enzymatic acylation of nucleosides. In Pseudomonas cepacia lipase-mediated benzoylation of floxuridine (FUdR), the enzyme performances, including enzyme activity and 3′-regioselectivity, were significantly enhanced by using [C 4MIm]PF 6-containing systems. It was observed that the enzyme performances not only depended on the anion of IL, but also on the cation, and that a proper combination between the cation and anion was critical to allow the enzyme to exhibit excellent performances. The optimal IL content in IL-containing systems is 5% (v/v). To gain a deeper insight into enzyme recognition, we extended benzoylation of FUdR catalyzed by P. cepacia lipase to its analogs. FUdR and its analogs could be biotransformed to the desired product by P. cepacia lipase in excellent conversion (>99%) and good to excellent 3′-regioselectivity (81–99%). Furthermore, the 3′-regioselectivity of P. cepacia lipase was enhanced with the increase of hydrophobicity of 5-substituent of the substrates, due to better hydrophobic interactions with Leu287 present in the active site.

Effect of the modification of phenothiazine-labeled poly(ethylene oxide) on the solubility and enzymatic electrocatalytic reaction of glucose oxidase in water/1-butyl-3-methylimidazolium tetrafluoroborate mixtures

In water/1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4]) mixtures, the solubility and electrocatalytic properties are compared between native glucose oxidase (GOx) mixed with phenothiazine-labeled poly(ethylene oxide) (PT-PEO) mediator and GOx-(PT-PEO) hybrid, in which PT-PEO is covalently attached to the surface lysine residues, under a substrate-saturated and diffusion-limited condition. The electrocatalytic current ( I cat) of native GOx mixed with PT-PEO is observed only in the mixtures with low IL content (∼30 wt%) wherein GOx is soluble and decreases with increasing the content of IL. The decrease in I cat is not fully attributable to the reduction in the diffusion rate of mediators due to the increase in the viscosity of the mixtures, suggesting the deterioration of the electron transfer (ET) reaction from FADH 2/FADH to PT +-PEO ( k et). The modification with PT-PEO not only increases the solubility of GOx but also enhances the k et. The k et value of the hybrids is less influenced by the IL addition than that of the mixed systems, resulting in the smaller dependence of I cat on the IL content and the I cat value larger than that of the corresponding mixed system with the same ratio of [PT-PEO]/[GOx].

Net Soil Nitrogen Mineralization in Chinese Forest Ecosystems

A better understanding of the effect of temperature and moisture on soil microbi al activity can improve our ability to predict soil N mineralization. The object ive of this study was to evaluate the effects of temperature (t) and soil mo isture (wfps: water filled pore space) on soil nitrogen mineralization in Ch inese fo rest ecosystems. The soil cores were kept in PVC tubes, adjusted to different so il water content, and separately incubated at four temperatures for 30 days. The inorganic N in soil extracts before and after incubation was analyzed. The resu lts showed that soil nitrogen mineralization rate (R min ) and nitrifica tion r ate were linearly related to t and wfps (p0.001). Three dimensional equ ations were developed to describe these effects: R min =e -7.60+0.0 7×t+14.74×wfps-10.41×wfps 2 . We scaled up the effect of temperature and moisture on soil nitrogen minerali zation to a national scale. Field measurements agree with the estimate of the re gression model.

Determination of oil in sunflowerseeds

AbstractOil content measurement in sunflowerseeds on an “as is” basis by current official methods is often associated with poor reproducibility. This study shows that the main factor contributing to this poor agreement is the particle size to which seeds are ground. This invariably influences the homogeneity of the bulk ground sample from which subsequent subsamples are taken. It is therefore suggested that oil content determinations on sunflowerseeds should be carried out on seed samples that have been evenly and finely ground, to a particle size not greater than 2.0 mm, in a mechanical mill such as the Ultra‐Centrifugal mill. Other factors investigated were seed composition (free husk, empty husk, crude fiber and seed meats) and structural differences in the seeds by light microscopy.

Variation in the oil content and fatty acid composition of field beans (Vicia faba) and peas (Pisum spp.)

AbstractOil content has been found to range from 1.2–1.9% in a wide range of diverse field bean (Vicia faba) cultivars, populations and selections and from 1.4–2.8% in a narrower range of pea cultivars. The ranges in fatty acid composition for beans and peas respectively were palmitic, 13.9–21.0% and 12.0–16.6%, stearic 2.2–3.5% and 2.5–4.2%, oleic 15.0–33.0% and 14.2–33.3%, linoleic 41.3–59.7% and 43.7–60.9%, linolenic 2.6–4.9% and 6.4–13.4%. Environment exerted a significant effect on the oil content of field beans but cultivar differences remained apparent. The analysis of whole or milled field beans stored for up to 5 years showed only minor losses of oil and component fatty acids. In both species over 90% of the total oil content was found in the cotyledons. Cultivar differences in whole grain oil content were associated with the concentration of oil in the cotyledons and appeared independent of the relative proportions of either embryo or seed coat. The interrelationships between oil content and other seed characteristics were also determined and the significance of these results in relation to plant breeding are discussed.