Emulsions, benzene-sodium

Estrone methyl ether (100 g, 0.35 mole) is mixed with 100 ml of absolute ethanol, 100 ml of benzene and 200 ml of triethyl orthoformate. Concentrated sulfuric acid (1.55 ml) is added and the mixture is stirred at room temperature for 2 hr. The mixture is then made alkaline by the addition of excess tetra-methylguanidine (ca. 4 ml) and the organic solvents are removed. The residue is dissolved in heptane and the solution is filtered through Celite to prevent emulsions in the following extraction. The solution is then washed threetimes with 500 ml of 10 % sodium hydroxide solution in methanol to remove excess triethyl orthoformate, which would interfere with the Birch reduction solvent system. The heptane solution is dried over sodium sulfate and the solvent is removed. The residue is satisfactory for the Birch reduction step. Infrared analysis shows that the material contains 1.3-1.5% of estrone methyl ether. The pure ketal may be obtained by crystallization from anhydrous ethanol, mp 99-100°. Acidification of the methanolic sodium hydroxide washes affords 10-12 g of recovered estrone methyl ether. 

Reactions between aromatic hydrocarbon radicabcations and cyanide ions, with few exceptions, give low yields of nuclear substitution products [76], In some cases, better results have been obtained by anodic oxidation of the aromatic compound in an emulsion of aqueous sodium cyanide and dichloromethane with tetra-butylammonium hydrogen sulphate as a phase transfer agent [77, 78]. Methoxy-benzenes give exceptionally good yields from reactions in acetonitrile containing tetraethylammonium cyanide, sometimes with displacement of methoxide [79, 80]... 

When acetic acid is diffusing from a 1.9 iV solution in water into benzene, spontaneous emulsion forms on the aqueous side of the interface, accompanied by a little interfacial turbulence. Results can be obtained with this system, however, if in analysing the refractive index gradient near the surface a correction is made for the spontaneous emulsion the rate of transfer is then in excellent agreement (57) with Eq. (20) (Fig. 6). Consequently there is no appreciable energy barrier due to re-solvation of the acetic acid molecules at the interface, nor does the spontaneous emulsion affect the transfer. With a monolayer of sodium lauryl... 

Deionized water (720 g), sodium lauryl sulfate (4.3 g), dioctanoyl peroxide (40 g), and acetone (133 g) were emulsified using an ultrasonic probe for 10 minutes. The step 1 polystyrene seed (48.0 g seed, 578 g latex) was added to the emulsion together with lauryl sulfate (0.8 g) and acetone (29.6 g). The mixture was transferred to a flask and left to agitate at approximately 25°C for 48 hours. Acetone was then removed and the solution added to a 5-liter double-walled glass reactor. The temperature was increased to 40°C while styrene (336 g) and divinyl benzene (0.88 g) were added drop-wise over approximately 60 minutes. After 4 hours the mixture was treated with deionized water (1200 g), potassium iodide (1.28 g), and polyvinyl pyrrolidone (18.48 g) with the temperature increased to 70°C. The polymerization continued for 6 hours at 70°C and 1 hour at 90°C. Styrene-based oligomer particles with a diameter of 1.7 pm and with a narrow size distribution were obtained. 

A stiff emulsion is obtained consisting of 99 cc. of benzene, emulsified in 1 cc. of water, by about 0.05 per cent (by weight) of sodium oleate. If less than about 80 per cent (by volume) of benzene is used, the emulsion will not be homogeneous but will consist of a lower watery layer on which floats a creamy emulsion. 

Prepare a little magnesium oleate by treating a solution of sodium oleate with magnesium sulfate. Carefully wash the precipitate free from soluble impurities and dry at about 110°. Suspend 1 g. of the dry salt in 100 cc. of benzene and provide the flask with a reflux condenser. Boil until solution is obtained. Possibly the product is a colloidal dispersion rather than a very perfect solution. It has been found that a very little sodium oleate mixed with the magnesium oleate rendered the emulsions more permanent. 

In a flask of about 150 cc. capacity, put 5 cc. of concentrated magnesium oleate solution, 5 cc. of benzene, 9 cc. of water, and 1 cc. of 1 per cent sodium oleate. Shake vigorously and at intervals of about 1 min. interrupt the shaking and add 2-cc. portions of water until a total of 20 cc. has been added. It is not practicable to go above 96 per cent of water, and emulsions containing about 75 per cent are more satisfactory. 

Several metals, including iron, copper and tin, can fog emulsions. Emulsions can be partly stabilized by sequestering these metallic species with suitable ligands. Catechol derivatives are reported to be helpful in preventing fog from this source. Examples include 1,2-dihydroxy-benzene-4-sulfonic acid (sodium salt) and l,2-dihydroxybenzene-3,5-disulfonic acid (disodium salt).37... 

Bartholme t al. (22) found for styrene with persulfate initiation and a sodium alkyl benzene sulfonate emulsifier that there was a discrepancy between their measured value of E (21.7 kJ mol- ) and that calculated (on the assumption that Att = 0) from the expression EN = /5(E - E ). However their value of E (which was derived from measuremlnts of the rate of seeded emulsion polymerization experiments in which N was the same at all temperatures) now seems to be too high probably because the average number of radicals per particle, n < 0.5 at the lower temperatures taking E =32.5 kJ mol-1 as the best estimate, AHg can be calculated rom AHg = /2(E (exp) - E (calc))... 

In the present experiments greatly enhanced rates of thermal emulsion polymerization were observed when potassium octadecanoate or sodium dodecyl sulfate (at 0.12 mol dm ) whereas sodium dodecyl benzene sulfonate and Triton1 X-100 (Rohm Haas, a non-ionic emulsifier octylphenoxypoly(ethyleneoxy)-ethanol) did not enhance the rate. The conversion after 12 hr at 60 °C with potassium octadecanoate was 69 % whereas with sodium dodecyl benzene sulphonate it was only 29 % (Fig. 2). 

The extraction of the pyridone from the aqueous solution is difficult when benzene or ether is used as a solvent. i-Methyl-2-pyridone, when dry, is very soluble in ethyl ether, benzene, and most organic solvents. It is, however, practically insoluble in petroleum ether or ligroin. When a mixture of water, benzene, and a little pyridone is shaken together all the pyridone is found in the water layer. When the pyridone is salted out from water by adding a sufficient quantity of potassium carbonate, the oily layer does not dissolve when benzene or ethyl ether is added, but three layers are formed. The pyridone seems to be extracted by ether or benzene only when the aqueous solution is strongly saturated with sodium hydroxide or potassium hydroxide and then the tendency to form an emulsion is so great that separation of the layers is extremely difficult. 

For example, pentachlorophenol can be extracted from water samples with benzene [12]. To a preserved sample (volume <1 1), 30 ml of benzene are added and the mixture is stirred for 45 min. The benzene phase is transferred into a separating funnel and the extraction is repeated with 30 ml of benzene for 30 min and 10 ml of benzene for 10 min. Sodium sulphate, isopropanol and/or methanol is used to break any emulsion. The combined benzene extracts are further extracted once with 40 ml and twice with 30 ml of 0.1 MK2C03 solution. The aqueous phase is used for derivatization. 

A troublesome emulsion sometimes results after benzoyla-tion. This may be broken up usually by the addition of more strong sodium hydroxide solution. In case an emulsion is formed which cannot be broken it is possible to extract the product with benzene. 

One can observe similar effects If the same surfactants are used as emulsifying agents. Table ill shows results obtained in benzene - aqueous two molar sodium hydroxide emulsions using different surfactants. AgAin It can be seen that the film forming cationic surfactant causes marked Increases In yields. 

Metalloporphyrin formation. Our earlier study of metal ion incorporation by TPP was carried out in a benzene in water micro-emulsion (ME) stabilized by cyclohexanol and a few different surfactants (.8). The Influence of Lewis bases, quinoline in particular, was studied in the ME system containing (anionic) sodium cetyl sulfate (SCS). For reasons to be discussed below, it was... 

From the discussion above, it is clear that there is no evidence for catalysis of persulfate initiation in emulsion polymerization systems. However, many ionic reactions have been shown to be subject to large catalytic effects in the presence of emulsifier micelles (Fendler and Fendler, 1975) so that the question arises as to whether there are any radical reactions that are subject to micellar catalysis and whether this phenomenon plays any part in any emulsion polymerization systems, Prima fade evidence that uiicellar catalysis may be important when emulsified monomer is allowed to polymerize thermally is provided by the work of Asahara et al. (1970, 1973) who find that several emulsifiers decrease the energy of activation for thermal initiation of alkyl methacrylate and styrene, [n particular, the energy of activation for thermal initiation of styrene emulsified with sodium tetrapropylene benzene solfonate was reported as S3 kl mol. much lower than any value determined in bulk. Hui and Hamielec s value of ] IS kj tnol (1972) seems to be representative of the data available on thermal initiation in bulk. The ctmclusions of Asahara et al. are based on observations of the temperature dependence of the degree of polymerization and are open to several objections. 

Diamino-2-phenyltriazole and nitrosobenzene, stirred in an emulsion of benzene and 12 N sodium hydroxide, gave 4-amino-2-phenyl-5-phenylazotriazole (60°C, 10 min, 72%) (70BCJ3587). Potassium permanganate in dilute acetic acid oxidized 4-amino-3,5-diphenyltriazole to 3,3, 5,5 -tetraphenyl-4,4 -azotriazole (25 °C, 30%). This product, stirred with hydrazine hydrate and palladized carbon in chloroform, gave 4-amino-3,5-diphenyltriazole (25°C, 1 hr, 91%) (70JOC2215). 

Aldehydes that contain only one a-hydrogen atom may be alkylated in reasonable yields with reactive alkylating agents such as methyl iodide, allyl chloride or benzyl chloride in an emulsion of benzene and 50% aqueous sodium hydroxide in the presence of a catalytic amount of a tetra-n-butylammonium... 

Emulsion polymerization typically refers to the polymerization of a nonaqueous material in water. The polymerization of a water-soluble material in a nonaqueous continuum has been called inverse emulsion polymerization. The inverse emulsion polymerization technique is used to synthesize a wide range of polymers for a variety of applications such as wall paper adhesive, waste water fiocculant, additives for oil recovery fluids, and retention aids. The emulsion polymerization technique involves water-soluble polymer, usually in aqueous solution, emulsified in continuous oil phase using water in oil emulsifier. The inverse emulsion is polymerized using an oil- or water-soluble initiator. The product is a colloidal dispersion of sub-microscopic particles with particle size ranging from 0.05 to 0.3 pm. The typical water-soluble monomers used are sodium p-vinyl benzene sulfonate, sodium vinyl sulfonate, 2-sulfo ethyl acrylate, acrylic acid, and acrylamide. The preferred emulsifiers are Sorbitan monostearate and the oil phase is xylene. The proposed kinetics involve initiation in polymer swollen micelles, which results in the production of high molecular weight colloidal dispersion of water-swollen polymer particles in oil. 

FIGURE 5.43 Histograms for the lifetimes of emulsion films AN/N is the relative number of films that have ruptured during a time interval At = 0.4 s. (a) Surfactant in the drops benzene films between water drops containing surfactant sodium octylsulfonate of concentration (1) 0 M, (2) 10 M, and (3) 2 x M. (b) Surfactant in the film (1) benzene film with 0.1 M of lauryl alcohol dissolved in the film, (2) water film with 2 X 10 M of sodium octylsulfonate inside. (From Traykov, T.T. and Ivanov, LB., Int. J. Multiphase Flow, 3, 471, 1977.)... 

Homopolymer DADMAC-Emulsion Polymerization. The equipment setup outlined in the solution polymerization was used to prepare the emulsion polymer. To the resin pot 321.5 g benzene, 138.5 g of 72.2% aqueous DADMAC monomer, and 40 g of 20% aqueous sodium octyl phenoxyethoxy-2-ethanol sulfate were added. The mixture was stirred at 170-180 rpm with a paddle stirrer and heated to 50° 1°C. The suspension was purged with nitrogen gas for 1 hr. Then, 7 ppm Fe+2 (added as Fe(NH4)2(S04)3 6H20) were added, followed by 2 X 10"3 mol f-butylperoxypivalate/mol monomer. The reaction mixture was stirred for 20 hr at 50° 1°C under a nitrogen blanket. The polymer conversion after 20 hr was 90 2%. The product was isolated by adding the benzene emulsion to acetone, filtering the product, and drying. 

DADMAC/Acrylamide Copolymer (75/25 Wt %)-Emulsion Polymerization. The following were added to the reaction vessel 64.4 parts benzene, 15 parts DADMAC, 5 parts acrylamide, 13.5 parts deionized H20, and 2 parts sodium octyl phenoxyethoxy-2-ethanol sulfate. The vessel was purged for 1 hr with N2 at 50° 1°C after which 5 ppm Fe+2 and 2 X 10"3 mol f-butylperoxypivalate/mol monomer were added. The temperature was held at 50° 1°C for 20 hr. The product, isolated via acetone precipitation, was found to be a DADMAC/acrylamide copolymer (60/40 wt %). 

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