Jacket double

Heaters. The preferred methods for heating are a double-jacket heated tank, nonmetaUic heat exchangers, quartz heaters, or Teflon-coated low watt density stainless steel heaters. Localized overheating must be avoided. 

Because hydrolytic reactions are reversible, they are seldom carried out in batch wise processes [26,28,36,70]. The reactor is usually a double jacket cylindrical flask fitted with a reflux condenser, magnetic stirrer, and thermometer connected with an ultrathermostat. The catalyst is added to the reaction mixture when the desired temperature has been reached [71,72]. A nitrogen atmosphere is used when the reactants are sensitive to atmospheric oxygen [36]. Dynamic methods require more complicated, but they have been widely used in preparative work as well as in kinetic studies of hydrolysis [72-74]. The reaction usually consists of a column packed with a layer of the resin and carrying a continuous flow of the reaction mixture. The equilibrium can... 

Hexanediol (0.5 mol/L), dimethyl fumarate (0.5 mol/L), toluene and Novozyme (33.3 g/L) are introduced in a thermostatted double-jacketted reactor fitted with a short thermostatted distillation column and a nitrogen inlet. The temperature is set at 60°C and a nitrogen flow (0.2 L/min) is bubbled into reaction medium. Methanol and toluene are collected in a flask and die volume of the solution is held constant by addition of toluene. After reaction (15 days) the catalyst is removed by filtration and the solvent is evaporated under reduced... 

Comparison between the heat exchanged per unit of volume during oxidation experiment in the Shimtec reactor and the maximal heat exchanged in a classical batch reactor (with a double jacket) highlights the effectiveness of the former. Indeed, in oxidation reaction experiments, a mean value of the heat exchanged per unit of volume in the HEX reactor is estimated with utility stream temperature of 47 °C ... 

A mixture of 2-iodotoluene (8.78 g, 0.04 mol) and trimethyl phosphite (24.8 g, 0.20 mol) was placed in a 45-ml, double-jacketed silica reaction vessel. The mixture was degassed by flushing with dry nitrogen for 5 min and irradiated with a 450-watt Hanovia (Model 679A-10) high-pressure quartz mercury vapor lamp fitted with an aluminum reflector head. The lamp was placed 5 cm from the inner portion of the reaction vessel. The reaction temperature was maintained at 0°C by the circulation of coolant from a thermostatically controlled refrigeration unit. Irradiation was continued at this temperature for 24 h. At the end of this time, the volatile materials were removed with a water aspirator, and the residue was vacuum distilled (96 to 97°C/0.25 torr) to give the dimethyl 2-methylphenylphosphonate (7.28 g, 91%). 

C. Fuxyt S,N,N, S -tetramethytdiamidophoaphate. To 180 mL of dry diethyl ether, chilled to -30°C, is added 56.7 g (4.2 equiv) (1.26 mmol) of dimethylamine (Note 17). This solution is added during 1-2 hr from a double Jacketed dropping funnel, protected from moisture by a calcium chloride-tube and connected to a cryostat regulated to -30°C, to a stirred mixture (Note 18) of 60 g (0.30 mol) of the freshly distilled furyl phosphorodichloridate and 250 mL of ether in a two-necked, 1-L flask equipped with a condenser, protected from moisture by a calcium chloride-tube and connected to the cryostat. This flask is chilled in an ice bath during the addition of the first two equivalents of the dimethylamine. After the addition of... 

The lamp (Figure 6 16) is mounted in a double jacket which would withstand mechanical strain due to explosion of the light source (e.g., upon rupture of the inner tube of protection). 

The reaction was carried out in an immersion-well photoreactor with a medium-pressure. 80-W Hg lamp in a water-cooled double jacket (quartz and Simax glass, sintered-glass inlet at the bottom of the reactor), and equipped with a dry icc cooled spiral cooler with an hydraulic seal. A mixture of 3,4,4-trifluoro-5.5-dimethyl-4.5-dihydrofuran-2(3//)-one (3 67 mg, 40 mmol) and solvent (2 mol) was irradiated for 10 h at 18-20 C in a stream of argon. The low-boiling part of the mixture was fractionally distilled off and the product was isolated by preparative GC (polybutane-1,4-diol succinate, 500 cm, 160-200 C) vicld 50-65%. 

By coupling an ultrasonic probe with a microwave reactor and propagating the ultrasound waves into the reactor via decalin introduced into their double jacket design, Chemat et al. studied the esterification of acetic acid with propanol and the pyrolysis of urea to afford a mixture of cyanuric acid, ameline and amelide (Scheme 9.19)136. Improved results were claimed compared to those obtained under conventional and microwave heating. The MW-US technique was also used to study the esterification of stearic acid with butanol and for sample preparation in chemical analysis137,138. 

A combination of different techniques can frequently improve yields of final compounds or synthetic conditions, for example a reunion of direct electrochemical synthesis and simultaneous ultrasonic treatment of the reaction system [715]. Reunion of microwave and ultrasonic treatment was an aim to construct an original microwave-ultrasound reactor suitable for organic synthesis (pyrolysis and esterification) (Fig. 3.7) [716], The US system is a cup horn type the emission of ultrasound waves occurs at the bottom of the reactor. The US probe is not in direct contact with the reactive mixture. It is placed a distance from the electromagnetic field in order to avoid interactions and short circuits. The propagation of the US waves into the reactor occurs by means of decalin introduced into the double jacket. This liquid was chosen by the authors of Ref. 716 because of its low viscosity that induces good propagation of ultrasonic waves and inertia towards microwaves. 

Heating is provided by a heating fluid flowing through a double jacket, and the interior is lined with two coils designed to perform a cooling function (immersed coil) or a foam-breaker function (exposed coil). The dissolution of an irradiated Pu/Al target requires two operations and leads to the preparation of 88 L of solution. 

Storage tanks. The total capacity of the storage tanks of each hot cell is given in Table III. The process tanks are double-jacketed for all the hot cells except Candide. This cell, designed initially for non-aqueous investigations, has small storage tanks placed directly on the alpha-cell work level. 

There are many different designs of condenser available, and the type used depends upon the nature of the reaction involved. The most common designs of condenser are the Liebig condenser (Fig. 9.25a), the coil condenser (Fig. 9.25b), the double-jacketed coil condenser (Fig. 9.25c), and the cold-finger condenser (Fig. 9.25d). Other condensers available tend to be simple modifications of these three types. 

The Liebig condenser, the coil condenser, and the double-jacketed coil condenser are similar in design and function. They are water-cooled via connection to a cold-water tap, in the case of the Liebig condenser the water flows in at the bottom and flows out at the top giving a jacket of cold water around the condenser stem and leading to a cold surface on the inside. Any volatile materials in the reaction condense on the cold outer surface and run back into the reaction mixture. The coil condenser functions in a similar way except that the cold surface is now on the inside of the condenser. This can offer an advantage in particularly humid locations because there is less tendency for atmospheric moisture to condense on the outside of the condenser and run down over the reaction vessel. The double-jacketed coil... 

Double jacket, vacuum, VAGAS gas stripping system ... 

Double jacket, vacuum gas-assisted vacuum (Transflo ) ... 

The most common source of indirect heat is steam in combination with heat exchangers or double jackets. The heat capacity introduced into the apparatus depends on the heat transfer coefficients, the heat exchange area and the temperature difference between steam condensation temperature and product temperature. 

On the technical scale, different types of reboilers have been developed [38], Depending on the distillation requirements, various reboiler constructions can be used. The simplest ones are heat exchangers or double jackets evaporators constitute more elaborate technical constructions. The advantage of the latter systems is generally the short residence time and the handling of products with difficult physical properties, such as those with high viscosity or a tendency to crystallisation. These evaporators have very short direct contact times and, therefore, allow distillation of heat-sensitive products. 

The process was performed by flowing the reagent mixture through a catalytic bed charged in a vertical double jacket glass column even after many runs the... 

A large flow of excess olefins is sometimes used to increase the growth rate (Zosel technique). This makes the reaction 5 to 16 times faster at between 160 and 170 0 The removal of heatiraises a particularly delicate technological problem. Owing to potential teaks in the cooling system, water cannot be used directly due to its affinity for aluminum alkyls. The double jacket system recommended uses an intermediate fluid (isopentane), which is itself cooled by water. 

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