Flavor and oxidative stability of hydrogenated and unhydrogenated soybean oils. Efficacy of plastic packaging

Soybean oils were packaged in polyvinylchloride, acrylonitrile, clear glass and amber glass bottles and their flavor stabilities were evaluated by a trained sensory panel. Hydrogenated and unhyrdogenated oils showed similar patterns of flavor deterioration regardless of container or type of aging. In accelerated light-exposure tests with air in the headspace, oils in plastic bottles showed flavor and oxidative stability equivalent to the same oils in clear glass bottles. Packaging in the amber glass bottle provided, as expected, significantly improved oil stability during light-exposure tests. In accelerated storage tests at 60 C with air in the headspace, sensory evaluation and peroxide determination showed no significant differences in oils packaged in clear glass and PVC, but sometimes oils received lower scores in glass compared with those in acrylonitrile bottles. During long-term storage, oils in plastic bottles with nitrogen in the headspace had flavor and oxidative stabilities equal to oils in glass bottles with nitrogen. These investigations indicate that packaging soybean oils in polyvinylchloride or acrylonitrile bottles is a viable alternative to packaging in clear glass bottles.     

气提法合成二甲基丙烯酸乙二醇酯

以乙二醇和甲基丙烯酸为原料,直接酯化法合成二甲基丙烯酸乙二醇酯,反应过程中通入空气代替带水剂带出反应生成的水。考察了氮气、氩气、二氧化碳与氧气以不同比例混合作为带水气体对反应收率的影响,结果表明,纯氮气、氩气和二氧化碳没有辅助阻聚作用,纯氧气的辅助阻聚作用比混合气体的辅助阻聚作用弱,空气是具有良好辅助阻聚作用的带水剂,可以减少阻聚剂的用量。还考察了反应温度、催化剂用量、醇酸摩尔比、反应时间、空气流量和阻聚剂用量对收率的影响,在催化剂对甲苯磺酸用量为反应物总质量的5%,n(乙二醇)∶n(甲基丙烯酸)=1∶2.4,通入的空气体积流量为0.2L/min,阻聚剂对苯二酚用量为反应物总质量的0.1%,反应温度110℃,反应时间3h的条件下,二甲基丙烯酸乙二醇酯收率达93.5%。     

工业中气相色谱法对氧含量的测定

讨论了利用空气作为标准气校准气相色谱的可行性,以及采用氢气作为载气,测出空气及氮中的氩含量。论述了测量氮中舍氧及氢中含氧的方法。     

Long term storage of soybean and cottonseed salad oils

Commercially prepared and packaged soybean and cottonseed salad oils from several different processors were evaluated periodically during storage for 12 months. Partially hydrogenated and winterized soybean oils, as well as unhydrogenated soybean salad oils, were stored in bottles and cans at 78 and 100 F. Control samples of all oils were held at 0 F during the entire test. Some lots in bottles and cans were packaged under nitrogen to improve storage stability. Agreement was good between organoleptic and oxidative evaluation of aged oils. After 26 weeks of storage at 100 F, the flavor of partially hydrogenated-winterized oils packaged under nitrogen showed a minimum loss. These same oils did not exhibit much, if any, reduction in their oxidative stability as indicated by storage peroxide values (active oxygen method). Soybean oil not protected with nitrogen demonstrated progressive flavor deterioration at 100 F. After 10 weeks of storage, the deterioration became marked and the flavor score was below 5. From limited observations, bottled oils appear to have a better stability than oils packaged in screw-cap tin cans. Hydrogenated oils packaged under nitrogen in cans had good oxidative stability, but some lowering of the flavor score was observed. Nonhydrogenated soybean oils packaged in tin cans not under nitrogen exhibited the most rapid flavor deterioration of all lots of oil investigated. Presented in part at the AOCS meeting, New York, October 1968 ARS, USDA     

Membrane/cryogenic hybrid scheme for argon production from air

A novel membrane/cryogenic hybrid scheme is presented wherein crude argon from a cryogenic air separation unit is fed to an oxygen selective membrane unit to remove a substantial portion of the oxygen. The oxygen enriched permeate from the membrane unit is returned to the crude argon distillation column of the cryogenic air separation process. The non-permeate stream is enriched in argon and can be further purified in a catalytic unit to produce an oxygen-free argon stream. The proposed process makes use of the synergy between the two separation units whereby, the cryogenic unit offers high recovery and the membrane provides purification leading to improved argon recoveries at higher argon concentrations. Calculations show that this process, in conjunction with an oxygen removal catalytic process, provides an economical alternative for the production of pure argon as compared to the conventional process using just a cryogenic unit and a catalytic unit to remove oxygen.     

Changes in virgin olive oil characteristics during different storage conditions

In this study we have examined the effect of olive oil storage outdoors on a comprehensive series of quality measures. The conditions used were at the extreme of those encountered during the production of bottle oil. Filtered and unfiltered oils were compared as was the influence of inert gas (nitrogen) in the headspace. Increases in K₂₃₂, K₂₇₀ and peroxides over time were very much reduced by inert headspace gas, which also reduced losses of total phenols and oxidative stability. Headspace nitrogen also reduced the rise in unconjugated phenolics as secoiridoid derivatives declined and minimised losses in polyunsaturated fatty acids. The pattern of volatile compounds detected in olive oils stored indoors or outdoors showed subtle differences. Moreover, when stored with air exposure the levels of some negative sensory components such as penten‐3‐ol and hexanal increased while other positives, like trans‐2‐hexenal were reduced. These changes would be expected to reduce quality. Finally, Panel tests were used. All oils lost perceived quality on storage and this was accelerated outdoors while headspace nitrogen slowed the deterioration significantly. Our data show that storage outdoors for 4 months in winter does not reduce olive oil quality significantly and that an inert gas in the headspace is beneficial. Practical applications : The storage of olive oil for bottling is carried out under a variety of conditions. Here we assess the effects of storage outdoors for oils from the main Greek cultivar (Koroneiki) of olive. Detailed analyses of quality (standard measures, different phenolics, lipids and volatiles) as well as Panel tests were used for evaluation. Our data show that, although storage outdoors causes deterioration quicker than indoors, changes are not serious up to 4 months. Furthermore, the use of an inert headspace gas significantly preserved quality both indoors and outdoors. Thus we would strongly recommend the latter measure to producers.     

内压缩流程空分的换热与精馏研究

分析和讨论了内压缩空分设备的氧氮两组分、氧氮氩三组分及氧氩两组分和氮氩两组分的相平衡,精馏部分的上塔、下塔、粗氩塔、精氩塔的精馏以及高压主换热器、低压主换热器、过冷器及主冷凝蒸发器等换热设备。希望能促进空气分离设备在理论方面的发展。     

The influence of air and its components on the cathodic stability of N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide

Although water- and air-stable ionic liquids have been in use for some years, experiments found in the literature are still performed in inert gas with ppm levels of oxygen and water. In this study, the influence of different environments (vacuum, argon, nitrogen, air and oxygen and water) on the cathodic electrochemical window of the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR₁₄TFSI) is reported and compared with investigations and processes found in the literature. The investigation indicates that this ionic liquid is highly stable in a vacuum and under argon flow. However, its cathodic stability is reduced in nitrogen and dry air. The simultaneous presence of water and air strongly affected the useful electrochemical window, as seen previously for imidazolium-based ionic liquids.     

Modification of nylon 6 by organochlorosilanes. I. Chemical reaction

The reaction of nylon 6 with dimethyldichlorosilane and vinylmethyldichlorosilane was investigated. Bright, 20-denier monofilament, nylon 6 yarns with 12.83% nitrogen, 61.16% carbon, and 10.16% hydrogen content were taken. Benzene or toluene was used as solvent for the reagents. The extent of reaction was estimated from the increase in weight of the parent yarn. Reaction was carried in the presence of nitrogen or in atmospheric oxygen (air). The per cent weight gain increased with increase in concentration of reagents, time, and temperature of the reaction. Viscosity and dyeability of the modified samples were measured, and in some samples the percentage of carbon, hydrogen, and nitrogen was also determined.     

在线分析仪在空分中的应用

根据空分设备工艺特点,要获得合格的产品氧、氮、氩,必须设置一些在线分析仪器进行监控。介绍了空分中典型的分析点以及在线分析所需要配置的分析仪器。     

Industrial trial to evaluate the effect of oxygen concentration on overall quality of refined, bleached, and deodorized soybean oil in PET bottles

Soybean oil, owing to its FA composition, is highly susceptible to deterioration by oxidation. The use of nitrogen gas permits the removal of dissolved oxygen and oxygen in the headspace of tanks and bottles. The objective of this work (an industrial trial) was to evaluate the shelf life of soybean oil packaged in polyethylene terephthalate (PET) bottles with different levels of oxygen in the headspace (<0.3, 5–6.5, 7–9, and >15%). The quality of the oil was evaluated during 6 mon. FFA and moisture increased and the smoke point decreased in all experimental conditions, even though the difference between the experiments was not significant. An increase was observed for peroxide value (PV), anisidine value (AV), and specific extinction, and higher increases in these parameters were observed in higher oxygen concentrations. After 180 d, the difference between the PV and AV was significant. According to sensory analysis, the shelf life of the oil increased from 60 to 90, 120, and 180 d as the initial concentration of oxygen was reduced from >15%, 7–9%, 5–6.5%, and 0–3%, respectively. The results demonstrated that shelf life of soybean oil packaged in PET bottles can be significantly increased by using nitrogen to reduce available oxygen in the headspace.     

Evaluation of capital cost data: Onsite utilities (industrial gases)

Capital cost correlations with capacity or with total investment are given for units supplying onsite industrial gases: compressed air, oxygen, nitrogen, inert atmospheres, high purity hydrogen, synthesis gas, ozone and acetylene. Costs are also given for units to remove carbon dioxide and water from gas streams. Correlations available in the literature and current data are compared. Graphs show the relative magnitudes of the different correlations, and the recommended correlation for each type of equipment is given. Some unit usages are given for producing some of the gases.     

Hydrophobic recovery of repeatedly plasma-treated silicone rubber. Part 2. A comparison of the hydrophobic recovery in air,water, or liquid nitrogen

Surfaces of medical grade silicone rubber (Q7-4750, Dow Corning) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen. Subsequently, the temporal behavior of the effects of the plasma treatment on the physicochemical surface properties of the silicone rubber was investigated using water contact angle measurements and X-ray photoelectron spectroscopy (XPS). Hydrophobic recovery during 3 months storage in ambient air was considerable and nearly complete for all four plasmas used. Hydrophobic recovery was almost completely suppressed during storage in liquid nitrogen, and only a minor increase of around 10° in advancing water contact angle was observed for all four plasma treatments. Also during storage of treated samples in water, hydrophobic recovery was minimal and initiated again by returning the treated samples to ambient air. XPS analyses showed that argon, carbon dioxide, and ammonia plasma-treated silicone rubber all had increased carbon percentages at the expense of oxygen and silicon after storage in water, or in liquid nitrogen, compared with after storage in ambient air. Interestingly, the carbon content of oxygen plasma-treated silicone rubber decreased during storage in water, or in liquid nitrogen, compared with storage in ambient air, while its oxygen and silicon percentages increased.     

Plasma polymer membranes from hexafluoroethane/hydrogen mixtures for separation of oxygen and nitrogen

Thin plasma polymer layers were produced employing feed mixtures of hexafluoroethane and hydrogen in an rf parallel-plate reactor. The layers are intended for use in membrane-based separation of oxygen and nitrogen. The hexafluoroethane-to-hydrogen mixture ratio was varied over a wide range, whereas all other process parameters (power, pressure, substrate temperature, and total gas flow) were held constant. The plasma polymers were examined by scanning electron microscopy, X-ray analysis, quantitative elemental analysis, and X-ray photoelectron spectroscopy. Permeability coefficients of oxygen and nitrogen and selectivities of the pure gases were determined. Pinhole-free plasma polymer films containing different amounts of fluorine, carbon, and hydrogen were formed. The distributions of fluorine and hydrogen in the products reflect their distributions in the feed gas. Traces of oxygen in some of the polymers are explained by the reaction of trapped radicals with atmospheric oxygen on the samples' exposure to air. Fluorine-containing carbon moieties such as CF₃, CF₂, and CF, and carbon moieties with fluorine atoms exclusively in secondary positions are present. A method of calculating crosslink density using the analytical data is described. The oxygen permeability coefficient and the selectivity of the plasma polymers increase as the hexafluoroethane content of the feed gas is raised. This behavior is attributed to growing solubility selectivity as a result of the rising fluorine content of the polymers. Maximum selectivity amounts to 3.4 at an oxygen permeability coefficient of 21 Barrer. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1517–1526, 1997     

利用吸收-水合耦合法从氨弛放气中回收氢气的研究(英文)

In this work, the absorption-hydration hybrid method was used to recover (hydrogen + nitrogen) from (hydrogen + nitrogen + methane + argon) tail gas mixtures of synthetic ammonia plant through hydrate forma-tion/dissociation. A high-pressure reactor with magnetic stirrer was used to study the separation efficiency. The in-fluences of the concentration of anti-agglomerant, temperature, pressure, initial gas-liquid volume ratio, and oil-water volume ratio on the separation efficiency were systematically investigated in the presence of tetrahydro-furan (THF). Anti-agglomerant was used to disperse hydrate particles into the condensate phase for water-in-oil emulsion system. Since nitrogen is the material for ammonia production, the objective production in our separation process is (hydrogen + nitrogen). Our experimental results show that by adopting appropriate operating conditions, high concentration of (hydrogen + nitrogen) can be obtained using the proposed technology based on forming hydrate.     

A pilot scale test of ozonization treatment of ethene wastewater for reuse

A pilot scale test of advanced treatment of ethene wastewater by ozonization was carried out for industrial water reuse. Effects of different operating conditions on COD degradation, such as wastewater flow rate, ozonized gas flow rate, operating voltage of ozonizer and two ozone generation means, using pure oxygen or air, was investigated. The results show that the increase of ozonizer operating voltage, the decrease of wastewater flow rate and the suitable ozonized gas flow rate improve the removal of COD in wastewater and that ozone generated respectively from air and pure oxygen can effectively remove COD of ethene wastewater to meet the industrial water reuse criterion.     

Products from the rapid pyrolysis of a brown coal in inert and reducing atmospheres

Yallourn brown coal and its calcium form have been pyrolysed in three different gas mixtures: 23% methane in argon, 50% hydrogen in argon, and 9.4% toluene in argon, at heating rates of 10⁷Ks^?1 and residence times of ≈2 ms. The products have been compared with those obtained in pure argon. The highly reactive molecule, ketene, was detected in the pyrolysate gases from both the ‘raw’ and calcium-form coals when pyrolysed in the above mixtures. Ketene was not detected in the pyrolysate gases, however, when the coals were pyrolysed in argon alone. When pyrolysed in 23% methane/argon the maximum yield of carbon monoxide from the ‘raw’ coal was found to be much lower than when pyrolysed in pure argon. The fully exchanged calcium-form coal when pyrolysed in pure argon, gave a maximum yield of carbon dioxide of oxygen content equal to the total oxygen content of the carboxyl groups originally present in the coal; the C0₂ yield from the ‘raw’ coal was about half that from the calcium-form in pure argon.     

Fundamentals of Glass-to-Metal Bonding: IV, Wettability of Gold and Platinum by Molten Sodium DisiIicate

Further studies were made on the effect of the nature of the atmosphere on the wetting of gold and platinum by sodium disilicate at 1000°C. The gases were oxygen, nitrogen, carbon dioxide, helium, argon, water vapor, carbon monoxide, hydrogen, and several mixtures of some of these gases. Data reported were obtained in the pressure range 10 ^-5 mm. of Hg to approximately 1 mm. of Hg. A special experimental apparatus was constructed for this purpose. In this pressure range the results showed that the wetting of gold was unaffected by these atmospheres. The platinum-sodium disilicate contact angle, on the other hand, depended on the nature and pressure of the gas. This angle was affected most by atmospheres of water vapor, carbon monoxide, hydrogen, and oxygen. Water vapor was found to be easily displaced from the metal by oxygen. The results were interpreted on the basis of selective adsorption of the gases at the various metal interfaces and of absorption of oxygen and hydrogen by platinum.     

Surface properties of glass plates activated by air,oxygen, nitrogen and argon plasma

Glass surface properties were investigated after air, nitrogen, oxygen and argon plasmas treatment. The samples were treated by low pressure plasma for 30 s with the gas flow 22 sccm. After modification kinetics of water spreading was measured. Surface topography was determined using optical profilometry, scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that using all types of gases plasma treatment leads to decrease of the surface roughness. The kinetics of water spreading depends on gases type used for glass plates modification. Analyzing the photoelectron spectra the increase of oxygen amount on the surface was observed. For the increase of wettability and adhesive properties of plasma treated glass, the introduction of new polar functional groups on the surface has greater influence than changing the surface roughness.