Showing papers on "Ethylene published in 1975"

Preparation of low and medium density ethylene polymer in fluid bed reactor

Abstract: A supported catalyst is used in the low pressure catalytic copolymerization of ethylene with C 3 to C 6 α-olefins in a fluid bed reactor to produce polymers having a density of less than 0.941 and a melt index of >0.0 to at least about 2.0. The supported catalyst contains about 0.05 to 3.0 weight % of chromium, about 1.5 to 9.0 weight % of titanium and >0.0 to about 2.5 weight % of fluorine.

All-valence-electron configuration mixing calculations for the characterization of the 1(π, π*) states of ethylene

Abstract: Configuration mixing (CM) calculations are reported for the 1 (π,π * ) and various other electronic states of ethylene. The configuration subspaces considered include all single and double excitations relative to a series of the most important terms in the CM expansion of each state. The lowest-lying 1 (π,π * ) transition is found to be essentially intra-valence in character with a calculated ∫ value in the 0.25–0.30 range, in good agreement with experiment. Diffuse 3dπ AOs are nevertheless found to be quite important in the representation of the 1 (π,π * ) state, even after extensive CM: failure to include them in the AO basis results in an energy increase of at least 0.7 eV and substantial overestimation of the corresponding ∫ value by as much as 50%. The vertical 1 (π,π * ) excitation energy is calculated to be 8.1 eV, while the corresponding 0-0 transition (90° twisted conformation) is predicted in the 6.0–6.2 eV range; very little change in CC bond length is found to occur upon torsion of the CH 2 groups in this state.

Inhibition of Methanogenesis in Marine Sediments by Acetylene and Ethylene: Validity of the Acetylene Reduction Assay for Anaerobic Microcosms

Abstract: Methanogenesis was irreversibly inhibited in sediments by concentrations of acetylene employed in nitrogen fixation assays (1 to 20%, vol/vol). Ethylene, but not ethane, also stopped methane production, and the inhibition was reversed by gassing with hydrogen.

Inhibition of in Vivo Conversion of Methionine to Ethylene by l-Canaline and 2,4-Dinitrophenol.

Abstract: l-Canaline, a potent inhibitor of pyridoxal phosphate-mediated reactions, markedly inhibited the conversion of methionine to ethylene and carbon dioxide by apple tissue. A 50% inhibition of methionine conversion into ethylene was obtained with 50 mum canaline and almost complete inhibition with 300 mum canaline. When 2,4-dinitrophenol, an oxidative phosphorylation uncoupler, was fed to apple tissue, it inhibited the conversion of radioactive methionine to ethylene by 50% at a concentration of 60 mum and by 90% at a concentration of 100 mum. Production of labeled carbon dioxide from acetate-1-(14)C was increased by 2,4-dinitrophenol, indicating that the inhibition of ethylene production was due to uncoupling of phosphorylation. Auxin-induced ethylene production by mungbean (Phaseolus mungo L.) hypocotyl sections was similarly inhibited by these inhibitors.These results support the proposal that pyridoxal phosphate is involved in the formation of ethylene from methionine, substantiate the requirement for ATP in ethylene production, and suggest that this ATP requirement occurs in the step (s) between methionine and ethylene. The biosynthetic mechanism probably involves activation of methionine by ATP followed by a pyridoxal phosphate-mediated gamma-elimination.

Comparison of Propylene-induced Responses of Immature Fruit of Normal and rin Mutant Tomatoes

Abstract: Continuous application of propylene to 40 to 80% mature fruits of normal tomato strains (Lycopersicon esculentum Mill.) advanced ripening in fruits of all ages by at least 50%. Although preclimacteric respiration was stimulated by propylene treatment, there was no concomitant increase in ethylene production. Once ripening commenced, the rates of endogenous ethylene production were similar in both propylene-treated and untreated fruits. Continuous exposure to propylene also stimulated respiration in immature fruits of rin, a nonripening mutant. Although respiration reached rates similar to those during the climacteric of comparable normal fruits there was no change in endogenous ethylene production which remained at a low level. Internal ethylene concentrations in attached 45 to 75% mature fruits of rin and a normal strain were similar. It is suggested that the onset of ripening in normal tomato fruit is not controlled by endogenous ethylene, although increased ethylene production is probably an integral part of the ripening processes.

Abscission: the initial effect of ethylene is in the leaf blade.

Abstract: The leaf blade of cotton (Gossypium hirsutum L. cv. Stoneville 213) was investigated as the initial site of ethylene action in abscission. Ethylene applied at 14 mul/l to intact 3-week-old plants caused abscission of the third true leaf within 3 days. However, keeping only the leaf blade of this leaf in air during ethylene treatment of the rest of the plant completely prevented its abscission for up to 7 days. This inhibition of abscission was apparently the result of continued auxin production in the blade since (a) the application of an auxin transport inhibitor to the petiole of the air-treated leaf blade restored ethylene sensitivity to the leaf in terms of abscission; (b) repeated applications of naphthaleneacetic acid to the leaf blade of the third true leaf, when the entire plant was exposed to ethylene, had the same preventive effect on abscission of this leaf as keeping its leaf blade in air; and (c) the inhibitory effect of ethylene on auxin transport in the petiole, which is reduced by auxin treatment, was also reduced by placing the leaf blade in air.The reverse treatment of exposing only the leaf blade of the third true leaf to 14 mul/l of ethylene, while the rest of the plant was kept in air, also did not cause abscission for up to 5 days. Auxin transport in the petioles of these leaves, however, was inhibited over 80% within 2 days and this effect presumably accounted for their increased sensitivity to ethylene during the subsequent exposures of the whole leaf to the gas.These results suggest that an initial and essential function of applied ethylene in abscission is to reduce the amount of auxin transported out of the leaf blade. This reduction together with the inhibitory effect of ethylene on auxin transport in the petiole reduces the auxin level at the abscission zone to a point where the cells in this region become responsive to the more direct action of the gas (e.g., enzyme induction and secretion). This sequence of events accounts for the lack of abscission unless ethylene is applied to both the leaf blade and the abscission zone.

Process for manufacturing hydrocarbons

Abstract: A catalytic process, employing a novel catalyst, for converting lower monohydric alcohols and their ethers, especially methanol and dimethyl ether, to a hydrocarbon mixture mostly ethylene, propylene and mononuclear aromatics. The novel catalyst is a composite of antimony oxide and a crystalline aluminosilicate zeolite such as ZSM-5.

The effects of ethylene in the root environment upon the development of barley

Abstract: Following observations that ethylene can occur in anaerobic or partially anaerobic soils at concentrations which can affect plant growth, shoot and root growth of barley plants, maintained in solution culture, were examined after long-term exposure of the roots to ethylene in air; the subsequent growth on transfer to a similar but ethylene-free environment was also studied. Both root and shoot dry weights were reduced slightly by the ethylene treatment; seminal root extension was inhibited greatly while lateral root growth was stimulated; absorption of ions and their transport from root to shoot within the plant was not affected. On transfer to an ethylene free environment the extension rate of the seminal axes increased markedly and was the greater the shorter the period of the preceding ethylene treatment; the extension of laterals initiated during the ethylene treatment was stimulated greatly but the growth of those formed subsequently was inhibited.

Process and apparatus for the manufacture of a gas mixture containing acetylene, ethylene, methane and hydrogen, by thermal cracking of liquid hydrocarbons

Abstract: A process for the manufacture of a gas mixture containing acetylene, ethylene, methane and hydrogen by cracking a liquid hydrocarbon by means of a plurality of arcs burning under the surface of the liquid hydrocarbon and limited, in their electrical effect, by current-limiting elements, wherein the total energy acting on the system is distributed by an arrangement of the electrical components, which is responsible for the stability of the arcs, over a plurality of localized burning points, the current-limiting components being matched to the voltage so that the output of each individual arc on average does not exceed 1.2 kW.

Catalyst for the oxidation of ethylene to ethylene oxide

Abstract: When supported silver materials are being prepared, deposits of from about 4.0 × 10.sup. -5 to about 8.0 × 10.sup. -3 gram equivalent weights per kilogram of finished product of ionic, higher alkali metals, i.e., ionic potassium, rubidium or cesium simultaneously with the deposit of silver improves the selectivity of these materials as catalysts for ethylene oxide production. Particularly good results are obtained with potassium.

Process for preparing elastomeric copolymers of ethylene and higher alpha-olefins

Abstract: High yields of elastomeric copolymers of ethylene and higher alpha-olefins, or of ethylene, higher alpha-olefins and unsaturated monomers (polyenes) containing two or more double bonds are obtained by copolymerizing a mixture of the monomers in contact with a catalyst prepared by mixing a catalyst-forming component which is an organometallic compound of aluminum with a supported catalyst-forming component obtained by contacting a halogenated titanium compound with a carrier or support consisting of or comprising an anhydrous Mg or Mn halide partially or completely complexed with a Lewis base capable of forming a complex with it. The copolymers so obtained have valuable mechanical properties, in particular a relatively low value of permanent set and do not exhibit excessive residual deformation at break.

Oligomerization reaction system

Abstract: Ethylene is oligomerized to even numbered alpha-monoolefins, predominantly in the range up to about C 40 , by contact at elevated pressure with nickel complex catalysts dissolved in polar organic solvents, preferably certain diols In the recovery of oligomers from the reaction product of this process, the ethylene-containing liquid oligomer product phase, after separation from the liquid solvent phase, is scrubbed with a clean portion of the organic solvent to remove catalyst complex, which may be recycled to the reaction zone Such catalyst removal prevents polyethylene formation during further processing of the product, thus avoiding fouling of process equipment and improving ethylene utilization as well as catalyst utilization

The Effect of Indole-3-acetic Acid and Other Growth Regulators on the Ripening of Avocado Fruits.

Abstract: Observations were made of the effects of several plant regulators, indole-3-acetic acid, kinetin, abscisic acid, and gibberellic acid, as well as of extracts prepared from leaves and fruit stalks on the respiration pattern, ethylene production, and the number of days to ripen of avocado fruits (Persea americana Mill.). These substances were vacuum infiltrated to insure good penetration and distribution. Kinetin, abscisic acid, gibberellic acid, and the extracts had no effect on either ripening time or on the respiration pattern and ethylene production of the fruits. Indoleacetic acid, however, had a marked effect on ripening. At high concentrations (100 and 1000 mum), indoleacetic acid stimulated respiration and induced preclimacteric ethylene production, resulting in accelerated ripening of the fruits. At the low concentrations (1 and 10 mum), it delayed ripening of fruits and suppressed the climacteric respiration and ethylene production. The results reinforce several previous observations with other fruits that auxins may largely constitute ;resistance to ripening' and may be responsible for the lack of ripening shown by unpicked fruits.

Process for the polymerization of ethylene

Abstract: Polyethylene or copolymers of ethylene with another α-olefin can be produced by the use of a novel polymerization catalyst obtained by using, in combination, (A) a specified, hydrocarbon-insoluble solid component prepared by reacting (i) a specific, hydrocarbon-soluble organoaluminum-magnesium complex (Al n Mg m R n (3 - .sub.α) 1 -R 2m 2 H n , wherein R 1 and R 2 are hydrocarbon radicals) with (ii) a titanium or vanadium compound containing halogen atom(s), and (B) an organoaluminum compound. This catalyst exhibits a surprisingly high activity per the unit amount of the solid component.

Oxidation of polymers in presence of benzene sulfonic acid or salt thereof

Abstract: This invention provides a process for the oxidation of copolymers of ethylene and olefinic monomers in the temperature range of from about -40° F to about 800° F. The oxidation is carried out in the presence of about 0.05 weight percent to about 1.0 weight percent based on copolymer/oil solution, of an oil soluble benzene sulfonic acid or salt thereof. These benzene sulfonic acids or salts thereof affect the rate of the oxidation reaction and/or the color of the oxidized product or amine reaction products thereof.

Process for the continuous production of an ethylene/vinyl acetate copolymer dispersion

Abstract: A process for the continuous manufacture of an aqueous ethylene/vinyl acetate copolymer dispersion which comprises continuously copolymerizing ethylene and vinyl acetate and optionally other α-olefinically unsaturated monomers, in an aqueous emulsion in the presence of an emulsifier and/or a protective colloid, and in the presence of a free-radical-forming redox catalyst system of a reducing agent and an oxidizing agent as well, optionally, as a heavy metal salt, and recovering said ethylene/vinyl acetate copolymer dispersion, characterized by (a) the presence of a molar excess of at least 3 times, preferably from 3 to 10 times, said reducing agent over said oxidizing agent dosed into the reaction medium and (b) adding the monomers continuously to the reaction mixture at such a rate that the concentration of unreacted monomers at no place in the reaction zone exceeds 15% by weight of the total weight of the reaction mixture.

Process for the recovery of ethylene oxide

Abstract: The conventional process for the recovery of ethylene oxide produced by the silver catalyzed, vapor phase, partial oxidation of ethylene with molecular oxygen involves a sequence of steps including absorption in water of the ethylene oxide contained in the reaction effluent. The ethylene oxide-containing absorbate is then stripped and the vapor thus generated is subjected to reabsorption, also in water. This invention provides an improved stripper-reabsorption system and includes the steps of partial condensation of the stripper overhead and introduction of an additional absorbent stream into the readsorption step.

Oxidative Turnover of Auxins in Relation to the Onset of Ripening in Bartlett Pear

Abstract: Pears (Pyrus communis var. Bartlett) kept in 100% O(2) showed an increase in the rate of softening, chlorophyll degradation, and ethylene evolution. The O(2) application could overcome, in part, the inhibition of ripening by 1 mm indoleacetic acid. Ripening of pears was also accelerated by the application of solutions containing indoleacetic acid-oxidation products, obtained by an overnight incubation of 0.1 and 1 mm indoleacetic acid with traces of H(2)O(2) and horseradish peroxidase. Although both treatments stimulated ethylene evolution, the promotion of ripening could not be attributed to an indirect ethylene effect. Indoleacetic acid oxidation products obtained in vivo by high O(2) tensions or in vitro by enzymatic degradation may function in the promotion of fruit ripening and the synthesis of ethylene.

Blends of copolyesters and ethylene/carboxylic acid copolymers which are at least ten percent neutralized

Abstract: Copolyesters blended with ethylene/carboxylic acid copolymer in which at least 10% of the acid groups are neutralized have increased melt strength, and are more readily processable by blow molding and extrusion film blowing techniques. The blends contain from 0.2 to 20% by weight of the ethylene/acid copolymer.