Vacuum evaporator

V acuum drying Vacuum dynamics Vacuum evaporation Vacuum furnaces Vacuum gas oil Vacuum gas oils (VGO)... 

Fig. 38. Caustic purification system a, 50% caustic feed tank b, 50% caustic feed pumps c, caustic feed preheater d, amonia feed pumps e, ammonia feed preheater f, extractor g, trim heater h, ammonia subcooler i, stripper condenser j, anhydrous ammonia storage tank k, primary flash tank 1, evaporator reboiler m, evaporator n, caustic product transfer pumps o, purified caustic product cooler p, purified caustic storage tank q, ammonia stripper r, purified caustic transfer pumps t, overheads condenser u, evaporator v, evaporator vacuum pump w, aqueous storage ammonia tank x, ammonia scmbber y, scmbber condenser 2, ammonia recirculating pump aa, ammonia recycle pump. CW stands for chilled water.

Solution crystalli tion (adiabatic evaporation (vacuum cooling))... 

A mixture of 0.1 mol of N-mono-1-p-chlorobenzohydrylpiperazine and 0.1 mol of 1-chloro-2-(2-hydroxy-ethoxy)-ethane is heated for 3 hours to 150°C. The mass is then taken up in 100 ml of benzene and 100 ml of a 10% aqueous solution of NaOH decanting takes place, and the benzene solution is washed with water and the solvent is evaporated. Vacuum distilling of the residue yields 1-p-chlorobenzohydryl-4-[2-(2-hydroxy-ethoxy)-ethyl]-piperazine, BP 220 C/0.5 mm Hg. 

Solution crystallisers are usually classified according to the method by which supersaturation is achieved, that is by cooling, evaporation, vacuum, reaction and salting out. The term controlled denotes supersaturation control whilst classifying refers to classification of product size. 

Snyder column Kudema Danish concentrator Nitrogen evaporation Vacuum... 

A mixture of 155 parts of 2-chloro-10-(y-chloropropyl)phenothiazine, 75 parts of sodium iodide, 216 parts of piperazine and 2,000 parts of butanone is refluxed for 8 hours, concentrated and extracted with dilute hydrochloric acid. The extract is rendered alkaline by addition of dilute potassium carbonate and extracted with ether. This ether extract is washed with water, dried over anhydrous potassium carbonate, filtered and evaporated. Vacuum distillation at 0.1 mm pressure yields 2-chloro-10-(y-piperazinopropyl)phenothiazine at about 214°C to 218°C. 

Other usual equipment for work-up and isolation, such as rotary evaporator, vacuum pump, and column chromatographic apparatus... 

Transmission Electron Microscopy (TEM) has been used to characterize aluminum thin films thermally evaporated (vacuum around 10 4 Torr) on Polyethyleneterephtalate (Mylar) and to correlate the crystallographic structure of the system Al/Mylar and the adhesion of the aluminum films. The adhesion of these films has been measured by a Peel test technique. For the polymer, an amorphous layer (t=12 nm) followed by a crystalline film have been observed on a Corona treated film and the opposite configuration has been found on a bi-axially stretched film. Some spherical precipitation ana interdiffusion zones have also be observed in the Mylar for the films which have the lower coefficient of adhesion (100 g/inch). The main conclusion is the augmentation of the adhesion of the aluminum film as the size of the grains decreases and/or as the microroughness of the Al/Mylar interface increases. 

If the liquid flowing to the surface and evaporating there contains dissolved materials, these materials will crystallize at the pore ends and form a crust (see Section 3.3.1). As long as evaporation takes place, the temperature of the agglomerate remains low due to the removal of heat of evaporation. Vacuum drying enhances this effect. It is, however, possible that the crust becomes so dense that no additional liquid can reach the surface while the core is still wet. If this happens, two alternative processes may occur ... 

Figure 11.21(a) schematically shows a structure composed of a twolayered carbon film deposited on an Al surface by the pulsed-evaporation vacuum technique. The structure consists of a diamond-like film (ta-C) with tetrahedral sp bonds between carbon atoms and an S-doped highly oriented sp -hybridized carbon film. Figure 11.21(b) represents the I-V characteristics of such a structure, which is a Al/sp carbon-sp carbon/Al junction. 

Solvent Evaporation Vacuum, Nj flow Lyophilization Few pLs to few mLs mLs Small-scale Pharmaceutically relevant and scalable Slow (may lead to degradation) concentrates excipients Must protect against drying induced degradation concentrates excipients Yes, only if solution composition reached at end of process... 

For high-throughput evaporation, vacuum centrifuges are currently the devices that are in most tvidespread use. Equipment using orbital shaking as an alternative has also become available from several vendors. 

LSD laboratories will have specific equipment for the construction of molecules under an inert atmosphere (eg. gas tanks of nitrogen or argon) and distillation of solvents under reduced pressure (rotary/ flash evaporator, vacuum pump, dry ice trap). Although this equipment can be used in the preparation of LSD this equipment is also used by conscientious chemists so as not to contaminate the environment with solvents or those who are working with heat or air sensitive molecules. 

Drying with anhydrous magnesium sulphate, evaporation (vacuum rotary evaporator), addition of acetonitrile, filtration (0.45 /xm). Pinal volume = 25 ml Addition of IS and concentration to 0.1-1 ml (N2)... 

Korchagin, A. I., Kuksanov, N. K., Lavrukhin, A. V. et al. 2005. Original production of silver nano-powders by electron beam evaporation. Vacuum 77 485-491. 

Freeze drying is a special case of drying under vacuum at a temperature below the triple point of water here water (ice) sublimes directly into water vapor. Although the heat required for sublimation is severalfold lower than for evaporation, vacuum operation is expensive. Freeze drying of coffee, for example, costs two to three times more than spray drying. On the other hand, the product quality and flavor retention are better. 

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