Lower ethylene

Propane cracking is similar to ethane except for the furnace temperature, which is relatively lower (longer chain hydrocarbons crack easier). However, more by-products are formed than with ethane, and the separation section is more complex. Propane gives lower ethylene yield, higher propylene and butadiene yields, and significantly more aromatic pyrolysis gasoline. Residual gas (mainly H2 and methane) is about two and half times that produced when ethane is used. Increasing the severity... 

Figure 11(a) shows the spectrum of adsorbed species on an active catalyst in a hydrogen-ethylene stream. This spectrum appears and stabilizes within minutes after hydrogen is blended into the ethylene stream. Three new bands appear in the presence of hydrogen at 2892, 2860, and 2812 cm-1. The appearance and location of these bands were verified by expanded scale spectra. Experiments at lower ethylene pressures reveal that there is an additional band at about 2940 cm-1 partially obscured in Fig. 11 by overlap of the ethylene spectrum. On a poisoned catalyst, which does not show the ZnH and OH bands, only the bands characteristic of chemisorbed ethylene are seen. 

Ethylene yields are reduced. Laboratory tests at Purdue University when ethane was pyrolyzed indicate the coke formation is directly related to lower ethylene yields. 

The data has been adapted from Table 8.1 to show the relative amounts of products at similar conversion levels. This indicates that the differences are mainly the considerably lower ethylene yield and higher propylene and C4 olefin yield (with the branched isomer dominant). 

EO/mole of parent alcohol and then gradually declined. Somewhat different behavior was observed using supercritical COj-extracted stock tank oil which had a higher carbon number 26 vs 16), a higher asphaltene content (1.52% vs 0.78%), and a higher combined acid and base number (0.85% vs 0.33) than the unextracted oil (see above). The maximum foam volume was observed at a lower ethylene oxide content (for 15 20 moles of EO vs 30 moles of EO for unextracted oil). The decline in foam volume with further increases in EO content was much more rapid in the presence of COj-extracted oil. This behavior was also observed for 5 alcohol ethoxyl-ates and Cg alcohol ethoxylates. 

However, it should be pointed out that conventional cracking conditions are not suitable for such feed stocks. Conventional cracking conditions lead to lower ethylene yields and to increases in fuel oil... 

An unusual aspect of Brookhart s Ni and Pd polymerization catalysts was that they could produce highly branched polyethylene, with the amount of branching controlled in large part by the ethylene pressure. Mechanistic studies indicated that facile /3-hydride eliminations on these catalysts under lower ethylene pressures enabled a chainwalking isomerization process shown in Figure 21. This leads to branching (sometimes extensive) of the growing... 

Common examples of miscible blends are ethylene-propylene copolymers of different composition that result in an elastomer comprising a semicrystalline, higher ethylene content and an amorphous, lower ethylene content components. These blends combine the higher tensile strength of the semicrystaUine polymers and the favorable low temperature properties of amorphous polymers. Chemical differences in miscible blends of ethylene-propylene and styrene-butadiene copolymers can also arise from differences in the distribution and the type of vulcanization site on the elastomer. The uneven distribution of diene, which is the site for vulcanization in blends of ethylene-propylene-diene elastomers, can lead to the formation of two distinct, intermingled vulcanization networks. 

The acrylic esters of the lower mono-, di- or trialcohols or the lower ethylene or propylene glycols are liquids of low viscosity and, especially with the lower alcohols, of repellent odor. They are often used in coating formulations as reactive diluents for the much more viscous oligomers. References to their toxicological properties can be found in Refs and... 

The monomers which are most widely used in photopolymerization processes to form networks are acrylates. The reason is that they polymerize fast. Methacrylates generally polymerize more slowly but, due to the stiffer main chain, yield harder products. By copolymerization of monoacrylates (/=2) with di-(/=4) or triacrylates (/=6), crosslinked networks are formed. In order to avoid the presence of free monomer in the cured product, monoacrylates are sometimes omitted. The acrylic esters of the lower mono-, di- or trialcohols or the lower ethylene or propylene glycols are liquids of low viscosity and, especially with the lower alcohols, of repellent odor. They are often used in coating formulations as reactive diluents for the more viscous oligomers. 

Thermal stability as determined by TGA and DTGA showed that the maximum rate of degradation of the hydrogenated polymers occurred around 450-460°C, and that the polymers with higher ethylene contents appeared to be more stable thermally than those with lower ethylene contents. 

The hydrocarbon liquids (e.g., ethane and propane) associated with this massive increase in the LNG system will create a significant supply increase for these liquids. The export of ethane from North America to Europe may become an important factor in lowering ethylene manufacturing costs in Europe over the next several decades. 

The Sclairtech technology also offers lower cost ethylene as an ethylene feed stream of 85% ethylene and 15% ethane maybe used in the process. The cost savings comes from lower ethylene purification requirements in the ethylene plant. 

Van Schooten and co-workers [1] have shown that ethylene-propylene copolymers prepared with VOCI3 or VOiORlj-containing catalysts not only contain odd-numbered methylene sequences, as was expected, but also sequences to two units. Some indications for the presence of methylene sequences of four units were found. Tanaka and Hatada [12] also investigated copolymers with much lower ethylene contents and pure polypropylenes prepared with catalysts consisting of VOCI3 or V0(0R)3 and alkylaluminium sesquichloride. 

---