Synthetic Rubber from Acetylene. III. The Preparation of Butadiene by Catalytic Hydrogenation Of Monovinylacetylene in the Gaseous Phase

1940 ◽  
Vol 13 (4) ◽  
pp. 856-860
Author(s):  
Zyunzi Hurukawa ◽  
Kôhei Nakaguti
Keyword(s):  
Water Vapor ◽  
Gaseous Phase ◽  
Heat Conductivity ◽  
Diatomaceous Earth ◽  
Maximum Yield ◽  
Hydrogenation Process ◽  
Heat Of Reaction ◽  
Synthetic Rubber ◽  
Series Of Experiments ◽  
Continuous Hydrogenation

Abstract Of the various technical methods for the preparation of butadiene from monovinylacetylene, the present authors chose to make first of all a thorough investigation of the continuous hydrogenation process, utilizing gaseous monovinylacetylene with various catalysts. As a result of this work the following conclusions were reached. The chief fault of this continuous hydrogenation process lies in the fact that, in addition to butadiene, large quantities of butene and oily polymerization products of monovinylacetylene are formed, as a result of which the yield of butadiene is small. This disadvantageous course of the reaction is attributable to the great heat of reaction which is evolved locally on the surface of the catalyst. In the experiments carried out by the present authors, the chief efforts were directed toward overcoming this drawback. As may be seen in Table II, a series of experiments were carried out with palladium as catalyst, which was used with excess carrier having a low heat conductivity, e. g., diatomaceous earth and Japanese acidic earth. This catalyst was expected to have a weakening effect on the activity, for this effect is very pronounced in the hydrogenation of acetylene to ethylene. In the present case, however, the results were unsatisfactory; dilution of the reaction gas with water vapor, a change in the gas current, and a change in the proportion of hydrogen to monovinylacetylene, were all tried. The maximum yield of butadiene at 80° C was 33.7 per cent, based on the monovinylacetylene.

scholarly journals l-Arginine Grafted Poly(Glycerol Sebacate) Materials: An Antimicrobial Material for Wound Dressing

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1457 ◽  
Author(s):  
Chia-Chun Wang ◽  
Ting-Yu Shih ◽  
Yi-Ting Hsieh ◽  
Jie-Len Huang ◽  
Jane Wang
Keyword(s):  
Water Vapor ◽  
Wound Dressing ◽  
Transmission Rate ◽  
Water Vapor Transmission Rate ◽  
Grafting Ratio ◽  
Chemical Conjugation ◽  
Water Vapor Transmission ◽  
Antimicrobial Material ◽  
Series Of Experiments ◽  
And Staphylococcus Aureus

This study focuses on the development and evaluation of a novel wound dressing material. l-arginine grafted poly(glycerol sebacate) materials (PGS-g-Arg) are developed by chemical conjugation of l-arginine on poly(glycerol sebacate) chains and the mechanical property, water vapor transmission rate, antimicrobial functions and biocompatibility are investigated. At various l-arginine grafting ratio, the mechanical properties are tunable. It was found that between 7–13% l-arginine grafting ratios, the tensile strengths of PGS-g-Arg were similar to that of natural skin. These materials are shown with a low water vapor transmission rate, 6.1 to 10.3 g/m2/h, which may form a barrier and assist in the closure of wounds. Inhibition in the growth of Pseudomonas aeruginosa and Staphylococcus aureus was observed on PGS-g-Arg, and a series of experiments were conducted to confirm its biocompatibility. In summary, l -arginine grafted poly(glycerol sebacate) may offer a novel option for wound dressing.

Run Parameters for a Continuous Hydrogenation Process Using ACMC-Pd To Replace Commercial Batch Reactor Processes

2018 ◽  
Vol 22 (12) ◽  
pp. 1622-1627 ◽  
Author(s):  
Robert J. Gulotty ◽  
Stephanie Rish ◽  
Andrew Boyd ◽  
Lee Mitchell ◽  
Scott Plageman ◽  
...  
Keyword(s):  
Batch Reactor ◽  
Hydrogenation Process ◽  
Commercial Batch ◽  
Continuous Hydrogenation

The Permeability of Rubber to Water Vapor

1943 ◽  
Vol 16 (2) ◽  
pp. 388-399 ◽  
Author(s):  
J. W. Van Dalfsen
Keyword(s):  
Water Vapor ◽  
Internal Structure ◽  
High Accuracy ◽  
Latex Films ◽  
Simple Method ◽  
Latex Particles ◽  
Methods Of Determination ◽  
Vulcanized Rubber ◽  
Series Of Experiments ◽  
Structure Of Matter

Abstract In connection with a study of various kinds of vulcanized rubber, including rubber films from vulcanized latex and latex films vulcanized in the dry state, it seemed desirable to investigate the packing of the latex particles. To what extent, for example, are these still present or are they coalesced? It is known that the diffusion of water vapor through solid substances may give an indication of the internal structure of matter. With this in mind, a search was made for a simple method to determine the diffusion of water vapor through rubber; high accuracy was not required so much as were simplicity and adaptability to a long series of experiments. Such a procedure was found in the method described by Hoekstra for determining the permeability of varnish films to water vapor. A detailed description of the method is given later in this paper. More accurate methods of determination, applied to rubber, have previously been described by others, but these procedures are less suitable for systematic tests.

Formation of Extreme Cold-Air Pools in Elevated Sinkholes: An Idealized Numerical Process Study

2005 ◽  
Vol 133 (4) ◽  
pp. 925-941 ◽  
Author(s):  
Günther Zängl
Keyword(s):  
Water Vapor ◽  
Heat Conductivity ◽  
Ambient Air ◽  
Heat Fluxes ◽  
Strong Temperature Dependence ◽  
Radiative Heat Loss ◽  
Cold Air ◽  
Process Study ◽  
Ground Heat Flux ◽  
Extreme Cold

High-resolution numerical simulations with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) are presented to investigate the processes leading to the formation of extreme cold-air pools in elevated sinkholes. The simulations are idealized in the sense that they are conducted with idealized model topography and with idealized large-scale conditions representing an undisturbed wintertime high pressure situation. After a number of model modifications, the temperature fields, radiative cooling rates, and sensible heat fluxes simulated by the model were in good agreement with the available observations, giving confidence that the model is suitable for this process study. The model results indicate a number of necessary preconditions for the formation of an extreme cold-air pool in a sinkhole. Apart from undisturbed clear weather, a small heat conductivity of the ground and an effective mechanism drying the low-level air during the cooling process are required. The importance of the heat conductivity results from the fact that the net cooling of the ground is only a small residual between the net radiative heat loss and the ground heat flux. As a consequence, extreme cooling events are strongly favored by the presence of freshly fallen powder snow. The necessity of a drying mechanism is related to the strong temperature dependence of the saturation vapor pressure, decreasing by a factor of about 2.5 per 10 K temperature decrease at temperatures below −20°C. Except in cases of very dry ambient air, a nocturnal cooling by 25 or 30 K (as observed in extreme cases) must be accompanied by an order-of-magnitude reduction of the water vapor mixing ratio to prevent the formation of fog. According to the simulations, the most effective drying mechanism is provided by the formation of ice clouds and the subsequent sedimentation of the ice particles. Near the surface, direct deposition of water vapor at the ground also seems to play a significant role.

Nitrogen requirement of sugar beet grown on mineral soils

1970 ◽  
Vol 74 (1) ◽  
pp. 37-46 ◽  
Author(s):  
D. A. Boyd ◽  
P. B. H. Tinker ◽  
A. P. Draycott ◽  
P. J. Last
Keyword(s):  
Sugar Beet ◽  
Nitrogen Fertilizer ◽  
Experimental Error ◽  
Crop Residues ◽  
Maximum Yield ◽  
Apparent Difference ◽  
Boulder Clay ◽  
Series Of Experiments ◽  
The Mean ◽  
Mineral Soils

SUMMARYThe effect of nitrogen fertilizer on the yield of sugar beet was tested in 170 experiments done between 1957 and 1966; results of 88 experiments, some testing five and six amounts of N, have not previously been published.On most sites, nitrogen increased sugar yields sharply and almost linearly up to an optimum beyond which yield changed little or decreased only slightly up to 1·8 cwt N/acre, the largest amount tested. In the two series of experiments giving most information, the mean increase from sub-optimal amounts of N was 2·5 cwt sugar/0·1 cwt N/acre.Usually 0·4–0·8 cwt N/acre was enough for maximum yield; more was needed on a few sites and on about a fifth of them nitrogen fertilizer was not needed. In 7 of the 10 years, the average optimum was 0·6–0·8 cwt N/acre; less was needed in the other years, the driest three years of the decade.In most, though not all, years, site-to-site differences in response between 0·9 and 1·8 cwt N/acre were no greater than could be expected from experimental error alone; much of the apparent difference in response between seasons were also attributable to this source.After taking account of experimental error, there were substantial between-site differences in response to amounts of N up to 0·9 cwt/acre, but attempts to explain them in terms of weather, soil and husbandry factors had little success. There was slight evidence of diminished responses to N where sugar beet followed crops other than cereals, and of responses somewhat greater than average on Chalky Boulder Clay soils of the Hanslope and Stretham Series; no other relationships were large or consistent enough to be useful for prediction.As between-site differences in response are largely unpredictable, and because a grower risks much greater crop losses by applying too little N than by applying too much, the recommended dressing is 1·0 cwt N/acre, substantially more than is needed, on the average, to obtain maximum yield. More N should be given on soils of the Hanslope and Stretham Series and on light sands poor in organic matter; less need be applied where crop residues are likely to supply much nitrogen.

scholarly journals Research of the reducing substances and pH yield kinetics of the wheat straw hydrolysates

2020 ◽  
Vol 63 (8) ◽  
pp. 118-124
Author(s):  
Irina V. Loginova ◽  
◽  
Maria V. Kharina ◽  
Keyword(s):  
Wheat Straw ◽  
Reducing Sugars ◽  
Maximum Yield ◽  
Process Conditions ◽  
Reaction Products ◽  
Initial Stage ◽  
Series Of Experiments ◽  
Ph Level ◽  
Reducing Substances ◽  
The Given

In low-acid hydrolysis, the temperature, pH, pressure, and the type of hydrolyzed material can have a significant effect on the yield of reducing sugars. The active acidity of the medium can undergo significant changes under the influence of the reaction products. The processes of hydrolytic decomposition can be facilitated by acetic acid, which is formed during the deacetylation of hemicelluloses, as well as the ability of natural biomass to neutralize acids. The level of neutralization potential (buffer capacity) depends on the type of biomass. The influence of the pH on the yield of reducing substances in the process of hydrolysis of wheat straw with dilute sulfurous acid in a wide temperature range is envistigated. The choice of optimal conditions for the release of reducing sugars is complicated by the need to compare the hydrolysis regimes with several interrelated parameters. In order to analyze the influence of different factors, a comparative assessment of the process conditions was carried out, under which the maximum yield of reducing substances was achieved in each series of experiments. The studies have shown that the initial stage of the process is characterized by a decrease in the actual pH level in hydrolysates, and the greatest change is observed in liquid autohydrolysis products. The pH of hydrolysates, depending on the process mode, varies in the range from 1.26 to 4.1, but the highest yield of reducing substances corresponds to pH values of about 2. It is shown that dimensionless values of the maximum concentrations of reducing substances graphically correspond to the given values of the medium.

The effect of CCC and nitrogen on the growth and yield of the second early potato variety Craig's Royal

1969 ◽  
Vol 73 (2) ◽  
pp. 245-259 ◽  
Author(s):  
H. P. M. Gunasena ◽  
P. M. Harris
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Tuber Yield ◽  
Potato Crop ◽  
Maximum Yield ◽  
Growth And Yield ◽  
Tuber Initiation ◽  
Time Of Application ◽  
Series Of Experiments ◽  
Nitrogen Treatments

SUMMARYThe experiment described here is the second of a series of experiments investigating the effect of the time of application of certain plant nutrients on the growth of the potato crop. In this experiment all combinations of three rates of nitrogen (0, 0·75 and 1·50 cwts nitrogen per acre), two times of application (at planting and at the time of tuber initiation) and two rates of application of CCC (0 and 4 lb/acre applied twice, shortly after emergence) were tested and studied by the technique of growth analysis.There was a linear relationship between leaf area duration (D)and tuber dry matter yield, D accounting for 95 % of the variation in the latter. The maximum amount of nitrogen accumulated in the leaves (Nmax) was linearly related to D, and accounted for 86 % of the variation in D. This relationship was improved if separate regressions were calculated according to whether CCC had been applied or not. Calculated in this way, the regressions indicated that more nitrogen was required for a given value of D when plants were treated with CCC.Delaying the application of nitrogen resulted in a considerable improvement in the recovery of fertilizer nitrogen (ammonium nitrate). A heavy dressing of nitrogen at the time of planting did not enable the crop to take up sufficient nitrogen for maximum yield. Because of these factors, delaying the application of nitrogen significantly increased tuber yield at both rates of nitrogen tested.Increasing the rate of nitrogen and delaying its application tended to increase the proportion of stem in the total dry matter; CCC had the opposite tendency. CCC, however, reduced leaf area and the mean effect of CCC was to reduce tuber yields. While there wore no significant interactions between CCC and nitrogen treatments on final tuber yield, it was observed that CCC slightly increased yield when the highest rate of nitrogen was applied late. Ways are suggested in which CCC may be more effectively used.

scholarly journals Reduction of Nitrogen Losses in Winter Wheat Grown on Light Soils

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2337
Author(s):  
Antoni Faber ◽  
Zuzanna Jarosz ◽  
Agnieszka Rutkowska ◽  
Tamara Jadczyszyn
Keyword(s):  
Winter Wheat ◽  
Maximum Yield ◽  
Nitrogen Losses ◽  
Winter Oilseed Rape ◽  
Gross Margin ◽  
Wheat Cultivation ◽  
N Dose ◽  
Use Efficiency ◽  
Series Of Experiments ◽  
N Rates

Two 16-year-old series of experiments with winter wheat grown in rotation after winter oilseed rape were used in the study. The experiments were located in the cold temperate dry and moist climate zones on light soils. Wheat was fertilized with nitrogen in the doses of 40, 80, 120, 160, and 200 kg N·ha−1 per year. Through the several years of the experiment, critical N rates for maximum yield and gross margin from the linear-plus plateau regressions were 149 ± 23.9 and 112 ± 23.6 kg N·ha−1, respectively. The estimated nitrogen indicators for these doses were as follows: nitrogen use efficiency (NUE) 93 and 108%, N surplus (Ns) 6.8 and −10.1 kg·N·ha−1, yield-scaled Ns, N2O, and NH3 3.5 and −0.2; 0.35 and 0.30; 0.31 and 0.25 kg N·Mg−1, respectively. Experiments have shown that two strategies for reducing nitrogen losses on light soils under wheat cultivation are possible: by limiting the N dose to the critical values due to the yield requirements, or due to the gross margin. The analysis of the 11-year data for 2300 farm fields with winter wheat grown on light soils showed that only 10% of them were implementing the first strategy, and as much as 90% chose the second strategy.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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