Liquid paraffin

About: Liquid paraffin is a research topic. Over the lifetime, 6185 publications have been published within this topic receiving 52956 citations.

Reduction of Nitrate to Ammonium in Selected Paddy Soils of China *1

Abstract: Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg -1 respectively. Three treatments were designed to keep the soil saturated with water: A) a 2 cm water layer on soil surface (with beaker mouth open); B) a 2 cm water layer and a 1 cm liquid paraffin layer (with beaker mouth open); and C) water saturated under O 2 free Ar atmosphere. The soils were incubated at 28 oC for 5 days. There was almost no 15 N labelled NH + 4 N detected in Treatment A. However, there was 1.4 to 3.4 mg N kg -1 15 N labelled NH + 4 N in Treatment B and 2.1 to 13.8 mg N kg -1 in Treatment C. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non labelled NH + 4 N in the original soils, 15 N labelled NH + 4 N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. DRNA process in soil suspension seemed to start after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms,did not facilitate DRNA process. DRNA occurred only when glucose was available and at the C/NO 3 - N ratio of over 12. It seemed that both availability and quality of the carbon sources affected DRNA.

Amination of alcohols, using Cu/Ni-based colloidal catalyst, for consecutive reaction system

Abstract: Animation of dodecyl alcohol and monomethylamine (MMA, di-functional) using Cu/Ni-based colloidal catalyst stabilized by barium stearate, and its kinetic study were performed to effectively synthesize didodecylmethylamine (DDMA). For the initial 3–4 h when MMA/dodecyl alcohol mole ratio was less than 1, the amination reaction proceeded very fast (72 mole-alcohol h-1 mole-Cu at 200 °) by zero-order kinetics to directly produce DDMA (85%), with complete consumption of MMA, without liberation of the intermediate, momomethyldodecylamine (MMDA) at all. Then, immediately after the mole ratio exceeded 1, the amination proceeded very slowly (3.4 mole-alcohol h-1 mole-Cu) by consecutive mechanism (second order) with liberation of MMDA. Aldolization of dodecyl aldehyde, formed by dehydrogenation of dodecyl alcohol, was found to be catalyzed by methylamines. Maintaining the zero-order kinetics by continuous control of MMA/alcohol mole ratio at less than 1 through out the amination is essential to obtain a highest DDMA yield by preventing the unwanted aldolization and transalkylation of MMA leading to various byproducts. Catalytic activity of the colloidal catalyst was sevenfold active than that of corresponding solid ones. Amination of 1,6-hexanediol and dimethylamine, using the colloidal catalyst and liquid paraffin as a solvent, was proceeded by consecutive mechanism to form N,N,N′,N′-tetramethyl-l,6-hexamethylenediamine with an yield of 80%.

Formulation and in vitro evaluation of Hydrodynamically balanced system for theophylline delivery.

Abstract: The objective of the present study was to formulate hydrodynamically balanced systems (HBSs) of theophylline as single unit capsules. They were formulated by physical blending of theophylline with hydroxypropyl methyl cellulose, polyethylene oxide, polyvinyl pyrrolidone, ethyl cellulose, liquid paraffin, and lactose in different ratios. These theophylline HBS capsules were evaluated for weight uniformity, drug content uniformity, in vitro floating behavior and drug release in simulated gastric fluids (pH 1.2). All these formulated HBS capsules containing theophylline were floated well over 6 hours with no floating lag time, and also showed sustained in vitro drug release in simulated gastric fluid over 6 hours. The theophylline release from these capsules was more sustained with the addition of release modifiers (ethyl cellulose and liquid paraffin). The drug release pattern from these capsules was correlated well with first order model (F-1 to F-5) and Korsmeyer-Peppas model (F-6 and F-7) with the non-Fickian (anomalous) diffusion mechanism. These experimental results clearly indicated that these theophylline HBS capsules were able to remain buoyant in the gastric juice for longer period, which may improve oral bioavailability of theophylline.

Nano-mesoporous molecular sieve synergistic intumescent flame-retardant rubber and preparation method thereof

Abstract: Nano-mesoporous molecular sieve synergistic intumescent flame-retardant rubber and a preparation method thereof relate to flame-retardant rubber and the preparation method thereof. The flame-retardant rubber provided by the invention comprises, by weight, 100 parts of a rubber matrix, 1.5-2.8 parts of a vulcanizing agent, 1-1.5 parts of a promoter CZ, 1-3 parts of stearic acid, 4.5-5 parts of zinc oxide, 1-2 parts of an antioxidant 4010, 1-3 parts of liquid paraffin, 30-40 parts of carbon black, 60-80 parts of an intumescent flame retardant, and 0-5 parts of nano-mesoporous molecular sieve. The preparation method provided by the invention comprises the following steps of: plasticating rubber in an open mill, successively adding eleaostearic acid, zinc oxide, the promoter CZ, the antioxidant 4010, the nano-mesoporous molecular sieve, carbon black, liquid paraffin, IFR and sulphur, mixing and discharging tablets, followed by sulfuration. By the adoption of the nano-mesoporous molecular sieve synergistic intumescent flame retardant, its excellent flame-retardant synergistic effect and interfacial compatibility effect greatly improve the flame-retardant performance and mechanical properties of the rubber material.