824 results about "Heptane" patented technology

The invention relates to a polymerization process of polyacrylonitrile with super high molecular weight, in particular to a method used to prepare high-performance polyacrylonitrile-based carbon fibre spinning dope. The method comprises the following steps: firstly, emulsifying agent is dissolved in heptane; then, acrylonitrile aqueous solution is added and stirred so as to be dispersed and emulsified; when dissolved in a small amount of heptane, initiator is dripped into the emulsified liquid (which is oil-soluble and enters into an external phase); nitrogen is pumped in and the reaction begins at 50 to 65 DEG C and at a stirring speed ranging between 200 and 1,000 r / min; after the reaction is finished, polyacrylonitrile powder can be obtained through deaeration and drying; and finally, spinning dope is obtained after the polyacrylonitrile powder is redissolved and deaerated. The polyacrylonitrile obtained according to the method has high molecular weight (i.e. Mw is more than 1,000,000) and substantially reduced molecular weight distribution (i.e. Mw / Mn is less than 2).

This invention relates to a process for the aromatization of C6 to C12 alkanes, such as hexane, heptane and octane, to aromatics, such as benzene, ethyl benzene, toluene and xylenes, with a germanium-containing zeolite catalyst. The catalyst is a non-acidic aluminum-silicon-germanium zeolite on which a noble metal, such as platinum, has been deposited. The zeolite structure may be of MFI, BEA, MOR, LTL or MTT. The zeolite is made non-acidic by being base-exchanged with an alkali metal or alkaline earth metal, such as cesium, potassium, sodium, rubidium, barium, calcium, magnesium and mixtures thereof, to reduce acidity. The catalyst is sulfur tolerant and may be pretreated with a sulfur compound, i.e., sulfided. The hydrocarbon feed may contain sulfur up to 1000 ppm. The present invention could be applicable to a feedstream which is predominantly paraffinic and / or low in naphthenes. Lowering the hydrogen to hydrocarbon ratio increases conversion and aromatics selectivity.

Unique thermoplastic (polypropylene, specifically) monofilament and / or tape fibers and yarns that exhibit heretofore unattained physical properties are provided. Such fibers are basically manufactured through the extrusion of thermoplastic resins that include a certain class of nucleating agent therein, and are able to be drawn at high ratios with such nucleating agents present, that the tenacity and modulus strength are much higher than other previously produced thermoplastic fibers (particularly those produced under commercial conditions), particularly those that also simultaneously exhibit extremely low shrinkage rates. Thus, such fibers require the presence of certain compounds that quickly and effectively provide rigidity to the target thermoplastic (for example, polypropylene), particularly after heat-setting. Generally, these compounds include any structure that nucleates polymer crystals within the target thermoplastic after exposure to sufficient heat to melt the initial pelletized polymer and allowing such an oriented polymer to cool. The compounds must nucleate polymer crystals at a higher temperature than the target thermoplastic without the nucleating agent during cooling. In such a manner, the “rigidifying” nucleator compounds provide nucleation sites for thermoplastic crystal growth. The preferred “rigidifying” compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as [2.2.1]heptane-bicyclodicarboxylic acid, otherwise known as HPN-68, sodium benzoate, talc, certain sodium and lithium phosphate salts [such as sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11]. Specific methods of manufacture of such inventive thermoplastic fibers, as well as fabric articles made therefrom, are also encompassed within this invention.