Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Solid additives

CCls CHO. A colourless oily liquid with a pungent odour b.p. 98°C. Manut actured by the action of chlorine on ethanol it is also made by the chlorination of ethanal. When allowed to stand, it changes slowly to a white solid. Addition compounds are formed with water see chloral hydrate), ammonia, sodium hydrogen sulphite, alcohols, and some amines and amides. Oxidized by nitric acid to tri-chloroethanoic acid. Decomposed by alkalis to chloroform and a methanoate a convenient method of obtaining pure CHCI3. It is used for the manufacture of DDT. It is also used as a hypnotic. [Pg.91]

Solids addition entrains air into inerted head space, creates flammable... [Pg.87]

Control rate of solids addition (e.g., size of opening in super sack)... [Pg.87]

The term filler is usually applied to solid additives incorporated into the polymer to modify its physical (usually mechanical) properties. Air and other gases which could be considered as fillers in cellular polymers are dealt with separately. A number of types of filler are generally recognised in polymer technology and these are summarised in Figure 7.1. [Pg.126]

The SIMULAR, developed by Hazard Evaluation Laboratory Ltd., is a chemical reactor control and data acquisition system. It can also perform calorimetry measurements and be employed to investigate chemical reaction and unit operations such as mixing, blending, crystallization, and distillation. Ligure 12-24 shows a schematic detail of the SIMULAR, and Ligure 12-25 illustrates the SIMULAR reaction calorimeter with computer controlled solids addition. [Pg.946]

This crude product is dissolved in 100 ml of dilute hydrochloric acid, the acid solution is extracted with ether, and the aqueous layer is made basic with sodium hydroxide solution (3N) in the presence of ether (approximately 250 ml). The ether layer Is separated, dried over potassium hydroxide and evaporated to a white solid. Additional purification by repeating the formation of the hydrochloric acid salt and reprecipitation of the base is carried out. When purified in this manner, followed by drying at 80°C in vacuo over phosphorus pentoxide, 2-chloro-11-(4-methyl-1-piperazinyl)dibenz[b,f] [1,4]oxazepine, li/IP 109° to 111°C, is obtained. [Pg.891]

Solid Hydrocarbons. Gilsonite (an asphaltite) and coal are used as very-low-specific-gravity solids additives. These additives do not require a great deal of water to be added to the slurry when they are used. [Pg.1196]

The kinetic principles operating during the initiation and advance of interface-controlled reactions are identical with the behaviour discussed for the decomposition of a single solid (Chaps. 3 and 4). The condition that overall rate control is determined by an interface process is that a chemical step within this zone is slow compared with the rate of arrival of the second reactant. This condition is not usually satisfied during reaction between solids where the product is formed at the contact of a barrier layer with a reactant. Particular systems that satisfy the specialized requirements can, however, be envisaged for example, rate processes in which all products are volatilized or a solid additive catalyzes the decomposition of a solid yielding no solid residue. Even here, however, the kinetic characteristics are likely to be influenced by changing effectiveness of contact as reaction proceeds, or the deactivation of the catalyst surface. [Pg.256]

In none of these examples is there any evidence that the catalytic behaviour results from direct chemical interaction between the solid reactant and the solid additive. [Pg.263]

The submitters used a two-necked, round-bottomed flask equipped with a magnetic stirbar, three-way stopcock connected to vacuum and a N2 source, and a solid addition tube. The addition tube was charged with methyl 4-iodobenzoate, tris(dibenzylideneacetone)dipalladium(0), and tri-o-tolylphosphine. After the zinc reagent was formed and the ice bath was removed, the solids contained in the addition tube were added in one portion by inverting the tube. [Pg.41]

The copper(I) bromide can also be added gradually from a solid addition apparatus such as a 50-ml. Erlenmeyer flask connected to a ground-glass adapter with a short piece of gouch tubing. [Pg.199]

Clear freshwater is the best drilling fluid in terms of penetration rate. Therefore it is desirable to achieve a maximal drilling rate using a minimal amount of solid additives. Originally low-solids mud formulations were used in hard formations, but they now also tend to find use in other formations. Several types of flocculants are used to promote the settling of drilled solids by flocculation. [Pg.4]

Aerosil. Aerosil as a solid additive in combination with diesel is active as a defoamer [962]. The aerosil is modified with bifunctional silicoorganic compounds. The composition is added to drilling solution in the form of a 3% to 5% suspension, in an amount of 0.02% to 0.5% by weight of aerosil per weight of drilling solution. [Pg.322]

Solubilizing all or part of a sample matrix by contacting with liquids is one of the most widely used sample preparation techniques for gases, vapors, liquids or solids. Additional selectivity is possible by distributing the sample between pairs of immiscible liquids in which the analyte and its matrix have different solubilities. Equipment requirements are generally very simple for solvent extraction techniques. Table 8.2 [4,10], and solutions are easy to manipulate, convenient to inject into chromatographic instruments, and even small volumes of liquids can be measured accurately. Solids can be recovered from volatile solvents by evaporation. Since relatively large solvent volumes are used in most extraction procedures, solvent impurities, contaminants, etc., are always a common cause for concern [65,66]. [Pg.891]

Manas-Zloczower, I., Dispersive mixing of solid additives, in Mixing and Compounding of Polymers—Theory and Practice. (I. Manas-Zloczower and Z. Tadmor, Ed.) Hanser Publishers, Munich, 1994, pp. 55-83. [Pg.201]

It is much more difficult to incorporate additives into polymers than it is into low viscosity liquids. Why is this What must occur, at the molecular scale, to incorporate a solid additive into a polymeric melt ... [Pg.131]

Two important terms used to describe additives in polymeric mixtures are distribution and "dispersion . When mixing polymers with additives, we want to create a system in which the additive is both well distributed and dispersed. Distribution refers to the even placement of the additive throughout the polymer. For example, a well made batch of chocolate chip cookies has good distribution of the chips if every bite has a chocolate chip in it. A poorly distributed cookie would have all its chips on one side. Dispersion, on the other hand, refers to the separation of the individual components of a solid additive into its smallest parts. Figure 10.6 illustrates both good and bad distribution and dispersion. [Pg.209]

How does surface treatment of polar solid additives lead to better dispersion and distribution of the additive in the polymer matrix ... [Pg.212]

The crude product is dissolved in a minimum amount of dichloromethane and adsorbed onto 25 g of silica gel (32-63 micron) by subsequent evaporation of the dichloromethane under reduced pressure. The sample of dry, dark brown silica gel is added to the top of a column containing 500 g of silica gel (32-63 micron) with a mobile phase of hexanes. The polarity of the mobile phase is gradually increased from hexanes to 95 5 hexanes-ethyl acetate. The fractions containing the desired product (Rf = 0.26, 95 5 hexanes-ethyl acetate) are combined and concentrated under reduced pressure to yield 6.9 g of 3 as a yellow solid. Additional purification is required to remove traces of tin by-products. Compound 3 is dissolved in 70 mL of... [Pg.51]

A 1-1., four-necked, round-bottomed flask equipped with reflux condenser, sealed stirrer, thermometer, and solid addition funnel and protected from atmospheric moisture with a Drierite guard tube is carefully dried and flushed with a dry inert gas (Note I). The flask is charged with 453 g. (3.1 moles) of silver difluoride (Note 2) and 500 ml. of l,l,2-trichloro-l,2,2-trifluoroethane (Note 3), and phenyl disulfide (100 g., 0.458 mole) (Note 4) is weighed into the solid addition funnel. The stirrer is started, and phenyl disulfide is added to the slurry in small portions. An exothermic reaction occurs, and after the addition of several portions the reaction mixture reaches a temperature of 40° (Note 5). By intermittent use of a cooling bath and by adjusting the rate of addition of the disulfide, the reaction temperature may be maintained between 35° and 40°. The addition of the phenyl disulfide requires 45-60 minutes. On completion of the addition the suspension of black silver difluoride has been converted to yellow silver monofluoride, and the exothermic reaction gradually subsides. The reaction mixture is stirred for an additional 15-30 minutes without external cooling and then quickly heated to reflux. [Pg.42]

To a dry 1-1., three-necked flask fitted with an efficient mechanical stirrer, a low temperature thermometer, and a solid addition assembly (Note 11) is added 97 g. (0.30 mole) of dibromoketone and 700 ml. of anhydrous tetrahydrofuran (Note 12). After the reaction vessel has been... [Pg.49]

Other PET grades are manufactured for packaging films, as well as for the production of video and audio tapes. These PET types are often standard grades with an IV of 0.64 dL/g. To reduce the sticking tendency of the final product, solid additives such as Si02 or china clay with specific particle sizes and particle-size distributions are incorporated by master-batch processes. The final product, the so-called BOPET, is a biaxial oriented PET film with high mechanical strength and a thickness between 1 and 180 im. [Pg.36]

Even less expected, perhaps, are the reactions involving gas-solid addition of HBr, Cl2, and Br2 to a, 3-unsaturated acid guest species in a- and P-cyclodextrin inclusion complexes (242). Although the chemical yields are not high, the optical yields in some cases are extraordinary. Thus, chlorine addition to methacrylic acid in a-cyclodextrin yields (- )-2,3-dichloro-2-methylpropanoic acid in nearly quantitative optical yield. The 3-cyclodextrin methacrylic acid clathrate undergoes chlorine addition to yield preferentially the enantiomeric (+ )-product, with an e.e. of 80%. [Pg.198]

B. (3-Bromo-3,3-difluoropropyl)trimethylsilane. A 1-L, four-necked flask is equipped with a mechanical stirrer, thermometer, Claisen adapter, septum inlet, reflux condenser (the top of which is connected to a calcium chloride drying tube), and a solid addition funnel. The flask is charged with (1,3-dibromo-3,3-difluoropropyl)trimethylsilane (78.3 g, 0.25 mol), and anhydrous dimethyl sulfoxide (200 mL), and the solid addition funnel is charged with sodium borohydride (11.5 g, 0.30 mol) (Notes 7 and 8). The stirred solution is warmed to 80°C, and sodium borohydride is added at a rate sufficient to maintain a reaction temperature of 80-90°C (Note 9). Toward the end of the addition, an additional portion of dimethyl sulfoxide (200 mL) is added via syringe to lower the viscosity of the reaction mixture. After the addition is complete, the mixture is cooled in an ice-water bath, diluted with 100 mL of pentane, and cautiously quenched with 12 M hydrochloric acid until no further gas evolution occurs. The mixture is transferred to a separatory funnel and washed with three, 100-mL portions of 5% brine. The pentane extract is dried over calcium chloride and the solvent removed through a 15-cm Vigreux column. Further fractionation yields 41.5 g (72%) of 3-bromo-3,3-difluoropropyltrimethylsilane, bp 139-141 °C (Note 10). [Pg.114]


See other pages where Solid additives is mentioned: [Pg.628]    [Pg.1809]    [Pg.23]    [Pg.86]    [Pg.135]    [Pg.135]    [Pg.349]    [Pg.663]    [Pg.262]    [Pg.416]    [Pg.601]    [Pg.10]    [Pg.618]    [Pg.210]    [Pg.210]    [Pg.210]    [Pg.230]    [Pg.232]    [Pg.148]    [Pg.62]    [Pg.451]    [Pg.476]   
See also in sourсe #XX -- [ Pg.192 ]

See also in sourсe #XX -- [ Pg.192 ]




SEARCH



© 2024 chempedia.info