Zinc oxide Propylene

Fig. 19. Spectrum of chemisorbed propylene (CD3—CH=CHa and CHs—CH=CDj) dotted line, chemisorbed CD3—CH=CHs on zinc oxide solid line, chemisorbed CII3— CH=CDj on zinc oxide.

The reactions described above are those expected if a 7r-allyl species is functioning as an intermediate. Thus, it appears that not only is the ir-allyl formed on zinc oxide but it is an important intermediate in the reactions of propylene. 

Results with butene are not as extensive as those with propylene. Nevertheless, on the basis of the ground work laid by the more extensive propylene studies, we are able to apply similar criteria to the more limited data for butene and conclude that a x-allyl species forms. Some preliminary studies suggest that two x-allyl species form from 1-butene (65), corresponding to the syn and anti forms. The results for propylene, the fact that x-allyl species form from butene, and the fact that zinc oxide is an effective catalyst for butene isomerization strongly suggest that these x-allyls are intermediates in the isomerization reaction. 

In comparison to the bismuth molybdate and cuprous oxide catalyst systems, data on other catalyst systems are much more sparse. However, by the use of similar labeling techniques, the allylic species has been identified as an intermediate in the selective oxidation of propylene over uranium antimonate catalysts (20), tin oxide-antimony oxide catalysts (21), and supported rhodium, ruthenium (22), and gold (23) catalysts. A direct observation of the allylic species has been made on zinc oxide by means of infrared spectroscopy (24-26). In this system, however, only adsorbed acrolein is detected because the temperature cannot be raised sufficiently to cause desorption of acrolein without initiating reactions which yield primarily oxides of carbon and water. 

The zinc oxide, titanium dioxide and cadmium sulphide photo-catalysed oxidation of an ethylene-propylene elastomer has been... 

Figure 15.2 Reactions of bis(diisopropyI)-thiophosphoryI disulfide (DIPDIS) with ethylene-propylene-diene rubber (EPDM) and zinc oxide. (From Reference 32 with permission from John Wiley Sons.)...

Myverol 18-99. See Glyceryl oleate Myverol 18-99K. See Rapeseed glyceride Myverol P-06. See Propylene glycol stearate 2MZ. See 2-Methyl imidazole MZO-25. See Zinc oxide N299 Carbon Black, N375 Carbon Black See Carbon black... 

PPG-5 lanolin alcohol ether PPG-10 lanolin alcohol ether PPG-20 lanolin alcohol ether Propylene glycol myristate emollient, wood Beeswax, synthetic emollient, zinc oxide Cetyl ricinoleate benzoate emulsifer... 

Propylene glycol Zinc oxide protectant, hydroxyl groups Diphenyl chlorophosphate Phenyl dichlorophosphate... 

N-octyl-isothiazolinone (Skane M-8) has been used mainly as a mildewcide in latex paints and sometimes also in oil-base paints. It is stabilized by the addition of either zinc oxide or formaldehyde in slightly alkaline formulation. Skane M-8 is supplied as 50% concentrate in propylene glycol which contains about 45% active ingredients and 5% impurities for use as a paint mildewcide. n-Octyl-isothiazoline is also marketed as Kathon 4200 and Kathon LM, and is supplied as 25% and 5% concentrates for use as a mildewcide for fabrics. The same active ingredient is also marketed as Kathon 893 and recommended as an industrial mul-... 

Glycerol 85 % is a less potent preservative than propylene glycol. It acts as a preservative above 30 %. In lower concentrations it is less effective. Microbiological challenge tests of a zinc oxide cutaneous suspension for example showed an insufficient effect in a concentration of 110 mg/g Glycerol 85 %. Therefore it was replaced with propylene... 

Additives used in final products Fillers barium and strontium ferrites, boron carbide, calcinated clays, calcium carbonate, carbon black, carbon-silica dual phase filler, clays, dolomite, fumed silica, iron oxide, magnesium aluminum silicate, magnesium carbonate, mica, montmorillonite, nickel zinc ferrite, nylon fibers, pulverized polyurethane foam, quartz, silica carbide, soapstone, talc, zinc oxide Plasticizers naphthenic oil, polybutene, aromatic oil, esters of dicarboxylic acid Plasticizers adipates, aromatic mineral oil, paraffin oil, phosphates, phthalates, polyethylene glycol, processing oil, sebacates Antistatics dIhydrogen phosphate of 8-amlnocaprolc add. Iodine doping Antistatics carbon black, quaternary ammonium salt, zinc oxide whisker Antiblocking diatomaceous earth Release propylene wax Slip erucamide+stearamide ... 

Dent and Kohes (27) proposed a definite bond between propylene and zinc oxide, infrared spectroscopy being used to study the sorption process. A series of articles by Gil-Av et al. (28-31) demonstrated the use of stationary phases containing silver nitrate to separate saturated and unsaturated compounds. 

Until they are vulcanized, elastic, amorphous ethylene-olefinic copolymers have very little possible utility except as components of caulks or sealants. However, grafting MA on the copolymers, using peroxide initiators, and compounding the modified materials with zinc oxide provides improved rubbers. A typical recipe would consist of 100 parts ethylene-propylene copolymer, 20 parts zinc oxide, 7 parts MA, and 2 parts BPO. Curing is carried out at 160°C for 30-45 min. Previously grafted copolymers, containing 2-5 MA residues, can also be cured with N-phenyl-B-naphthylamine initiator, steric acid modifier, and zinc oxide crosslinker. 

Fig. 3.31 Spectrum of chemisorbed propylene (CDj—CH=CH2 and CH,—CH=CD2) dottedline chemisorbed CD3—CH=CH2 on zinc oxide, solid Uiui chemisorbed CHj-CH=CD2 on zinc oxide. A band at 1413 cm is assigned to x (C-C-C)of x-allyl.

Acrylonitrile-butadiene rubber ((NBR) - Europrene N3960, acrylonitrile unit content 28 %) was purchased from Lanxess, and ethylene-propylene rubber ((EPM) Dutral CO 054, propylene unit content 40 %) was obtained from Montedison Ferrara. Crosslinking agents dicumyl peroxide DCP (Aldrich), triallyl-l,3,5-triazine-2,4,6(lH,3H,5H) TAC (Aldrich), zinc oxide ZnO (Huta Bfdzin), mercaptobenzothiazole MET (Pneumax MET) and sulphur Ss (Z.P.S. Siarkopx) ). 

Huang, S. Liu, S. Li, J. Zhao, N. Wei, W Sun, Y. Modified Zinc Oxide for the Direct Synthesis of Propylene Carbonate from Propylene Glycol and Carbon dioxide. Catal Lett. 2007,118,290-294. 

Flour, wheat. See Wheat (Triticum vulgare) flour Flowers of sulfur. See Sulfur Flowers of zinc. See Zinc oxide Fluorinated ethylene/propylene... 

FIG U RE 11.1 Typical contour plot to abbreviate compounding data (Vistalon 3708/Ethylene-Propylene Terpolymer, Enjay Chemical Company, 1968). Note that a compound with 200 parts each of oil and filler per 100 parts of rubber by weight (phr) still has a strength of about 1000 psi (7 MPa), quite acceptable for many mechanical applications. The compound, based on a high-molecular-weight ethylene-propylene terpolymer, also contains 5 parts zinc oxide, 1 part stearic acid, 1.5 parts sulfur, 1.5 parts tetramethylthiuram disulfide, and 0.5 parts of benzothiazyl disulfide. Cross-linking takes place at 160°C for 20 min. SRF, Semi-reinforcing furnace. 

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