Bonding extrusion

Hydroxy-THISs add to the C-C bond of diphenylcyclopropenethione (181. Inner salts without substituents in 5-posnion react similarly with diphenylcyclopropenone (Scheme 10) (4, 18). Pwolysis of the stable adducts (9) leads to rupture of the R-C-CY bond. Subsequent ring closure yields 10. When Y = O. 10 eliminates COS. producing 2-pyridone. When Y = S. 10 is isolated together with its isocyanate extrusion product, a thiopyran-2-thione (18). 

Making just one C—C bond by radical combination is not a prominent method for preparing heterocyclics, except for those cases in which the radical pair arises from a cleavage or extrusion reaction of a heterocyclic starting material. Such cases are treated below (Section 5.03.5.2.2). 

Addition on to the exocyclic C—C double bond of an alkylideneaziridine also occurs when this compound is allowed to react with organic azides (75JOC2045). The initially formed spirotriazolines (332) are converted into four-membered ring amidines (334) with extrusion of molecular nitrogen. In the case of phenyl azide, the amidine (334) is obtained alongside the triazoline (333). 

Thiirane 1,1-dioxides extrude sulfur dioxide readily (70S393) at temperatures usually in the range 50-100 °C, although some, such as c/s-2,3-diphenylthiirane 1,1-dioxide or 2-p-nitrophenylthiirane 1,1-dioxide, lose sulfur dioxide at room temperature. The extrusion is usually stereospeciflc (Scheme 10) and a concerted, non-linear chelotropic expulsion of sulfur dioxide or a singlet diradical mechanism in which loss of sulfur dioxide occurs faster than bond rotation may be involved. The latter mechanism is likely for episulfones with substituents which can stabilize the intermediate diradical. The Ramberg-Backlund reaction (B-77MI50600) in which a-halosulfones are converted to alkenes in the presence of base, involves formation of an episulfone from which sulfur dioxide is removed either thermally or by base (Scheme 11). A similar conversion of a,a -dihalosulfones to alkenes is effected by triphenylphosphine. Thermolysis of a-thiolactone (5) results in loss of carbon monoxide rather than sulfur (Scheme 12). 

Integral (or extruded). An aluminum outer tube from which fins have been formed by extrusion, mechanically bonded to an inner tube or liner. 

Current usage is almost entirely associated with the good adhesion to aluminium. Specific applications include the bonding of aluminium foil to plastics films, as the adhesive layer between aluminium foil and polyethylene in multilayer extrusion-laminated non-lead toothpaste tubes and in coated aluminium foil pouches. Grades have more recently become available for manufacture by blown film processes designed for use in skin packaging applications. Such materials are said to comply with FDA regulations. 

Early trailing edge design was eomprised of a C-shaped spar bonded to upper and lower facesheets with honeyeomb eore between (Fig. 36). The spar was either a simple extrusion if eonstant dimension, or built-up from two L-shaped legs if it needed to taper from one end to the other. Faeesheets were simple eonstant-thiekness sheet material. 

C. Dry Bonding Without Adhesives and Extrusion Coating Techniques... 

Process used provides different control capabilities. As an example closed molding (injection, compression, etc.) provides fine detail on all surfaces. Open molding (blow molding, thermoforming, spray-up, etc.) provides detail only on the one side in contact with the mold, leaving the second side free-formed. Continuous production (extrusion and pultrusion) yields products of continuous length. Hollow (rotational or blow) produces hollow products. These processes can be used creatively to make different types of products. For example, two molded or thermo-formed components can be bonded together to form a hollow product, or they can be blow molded. 

Sulphuranes - see also Dialkoxysulphuranes, Oxysulphuranes as intermediates 406 Sulphur bonding 484-493 Sulphur-containing groups, stereoelectronic effects of 584-594 Sulphur dioxide addition to 215-217 extrusion of 137, 140, 141, 158, 163, 397-402, 801, 805, 962, 1098 Sulphur monoxide, extrusion of 397-402 Sulphur trioxide, reactions of 217, 218 Sultenes, as intermediates 743 Sultines 679, 943 as photolytic products 881, 882... 

Since the new carbon-carbon bond is formed intramolecularly in the sulfide extrusion method, its main potential is to be seen in cases where intermolecular condensations fail.5,6... 

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