Heating methods autoclave

Taylor CR, Shi S-R, Chen C, et al. Comparative study of antigen retrieval heating methods microwave, microwave and pressure cooker, autoclave, and steamer. Biotech. Histochem. 1996 71 263-270. 

A hot air chamber used for heating or drying raw rubber, for vulcanising rubber products by the dry heat method, or for carrying out accelerated ageing by the air oven method. On the continent of Europe, the term oven is sometimes used in the sense of autoclave. 

Wet (hydrated) autoclave treatment represents the most uniform heating method and is claimed to be preferable over MWO irradiation by some authors (10,15). The main disadvantages of the autoclave method are that one must have access to an autoclave, and it can be time-consuming. 

Monoclonal antibody MIB-1 is used to recognize this antigen, and so the usefulness of this antibody is discussed in detail in Chapter 2. Immunohistochemical methods using microwave heating or autoclave treatment for localizing Ki-67 are presented. 

The pressure cooker-microwave heating method is simpler than the autoclave procedure and more efficient than microwave heating alone. The pressure cooker does not require checking the level of the antigen retrieval solution during heating in the microwave oven, and a large number of slides can be loaded simultaneously. In addition, the pressure... 

Precursor heating method. The gel mixture was maintained at 100°C for 3 days for precursor formation. The precursor with the mother liquor was transferred to autoclaves, and the temperature was raised at a constant rate of 1.7°C,min 1 to 130, 160, 190, and 220°C. The temperature was maintained at each level for 0.5 h. The synthesized materials were also treated in the same manner as the standard preparation method. XRD patterns showed that the zeolites prepared at 190 and 220°C were ZSM-34 however, the zeolite prepared at 220°C contained some sodalite structure. The zeolites crystallized at 130 and 160°C had insufficient XRD intensity of ZSM-34 patterns and showed an activity of only DME formation. When the crystallization temperature was raised to 190°C, DME decreased to ca. 1/10, and C2-C, olefins increased dramatically. However, when the crystallization temperature was raised to 220°C, ethylene formation decreased markedly and DME increased. 

Methyl fluoroacetate was first prepared by Swarts in small yield by the action of silver or mercurous fluoride on meth iodoacetate. The method is impracticable for large-scale work and therefore the preparation was reinvestigated in detail. Methyl chloroacetate was used in place of the expensive iodoacetate, and a variety of fluorinating agents was tried. It was found that fluorination could be effected by heating method chloroacetate in a rotating autoclave with potassium fluoride at 220° for 4 hr. Sodium fluoride, on the other hand, was almost without action. 

Figure 10.10 TEM and SEM images of MIL-101 particles nthesised using (a) autoclave and (b) microwave heating methods. The autoclaved samples show a more distinctive morphology compared to the microwave samples. Reprinted with permission from Bromberg et Cop5right 2012 American Chemical Society.

Sterilization is an important process that involves a major market for the use of plastics in packaging. The most common methods of sterilization are those using heat, steam (autoclaving), radiation, and gas (EtO—ethylene oxide) (see Tables 4-5 and 4-6). Unfortunately, each of these methods has its limitations. There are, however, plastics that do meet performance requirements based on the various different processes, including radiation. 

Secondary and tertiary amines are not generally prepared in the laboratory. On the technical scale methylaniline is prepared by heating a mixture of aniline hydrochloride (55 parts) and methyl alcohol (16 parts) at 120° in an autoclave. For dimethylaniline, aniline and methyl alcohol are mixed in the proportion of 80 78, 8 parts of concentrated sulphuric acid are added and the mixture heated in an autoclave at 230-235° and a pressure of 25-30 atmospheres. Ethyl- and diethyl-anihne are prepared similarly. One method of isolating pure methyl- or ethyl-aniline from the commercial product consists in converting it into the Y-nitroso derivative with nitrous acid, followed by reduction of the nitroso compound with tin and hydrochloric acid ... 

This procedure is representative of a new general method for the preparation of noncyclic acyloins by thiazol ium-catalyzed dimerization of aldehydes in the presence of weak bases (Table I). The advantages of this method over the classical reductive coupling of esters or the modern variation in which the intermediate enediolate is trapped by silylation, are the simplicity of the procedure, the inexpensive materials used, and the purity of the products obtained. For volatile aldehydes such as acetaldehyde and propionaldehyde the reaction Is conducted without solvent in a small, heated autoclave. With the exception of furoin the preparation of benzoins from aromatic aldehydes is best carried out with a different thiazolium catalyst bearing an N-methyl or N-ethyl substituent, instead of the N-benzyl group. Benzoins have usually been prepared by cyanide-catalyzed condensation of aromatic and heterocyclic aldehydes.Unsymnetrical acyloins may be obtained by thiazol1um-catalyzed cross-condensation of two different aldehydes. -1 The thiazolium ion-catalyzed cyclization of 1,5-dialdehydes to cyclic acyloins has been reported. 

Thymol has since been synthetised by a number of chemists, but only two of those syntheses need be considered in this connection because of their close relationship to the present method, Dinesmann (D.E.P., 125,097 (1900)) obtain a patent for a process of making thymol from 2-brom-p-cymene. This process consists in sulphonating 2-brom-p-cymene, obtaining 2-brom-3- or 5-sulphonic acid, which, when heated with zinc dust and ammonia in an autoclave at 170°, gives cymene-3-sulphonic acid. This compound on fusion with potassium hydroxide gives thymol. 

Dry heat sterilisation is used for equipment that can withstand high temperature and dry heat but cannot withstand wet or steam autoclave. This method is often used for glassware as it dries and sterilises in one operation. The pipets must be wrapped in dustproof aluminum foil or placed in metal pipette cans. The can lids are removed during heating and replaced after sterilisation, that is before any dust can get in the can. Disposable items are not recommended for dry heat sterilisation. This method may only be good for permanent reusable glass pipettes. 

HPA catalyzed liquid phase nitration was eairied out in a Teflon-lined stainless autoclave of 200 mL equipped with a magnetic stirrer. Reactants and HPA were quantitatively added to the autoclave, which was sealed and heated in an oil-bath. Products were analyzed by GC with OV-101 30 m capillary column and FID detector by using calibrated area normalization and internal standard method. All products were confirmed by GC-MASS analysis. 

The British Pharmacopoeia (1993) recognizes five methods for the sterilization of pharmaceutical products. These are (i) dry heat (ii) heating in an autoclave (steam sterilization) (iii) filtration (iv) ethylene oxide gas and (v) gamma or electron radiation. In addition, other approaches involving steam and formaldehyde and ultraviolet (UV) light have evolved for use in certain situations. For each method, the possible permutations of exposure conditions are numerous, but experience and product stability... 

Principles of the methods employed to sterilize pharmaceutical products are described in Chapter 20. The British Pharmacopoeia (1993) recommends autoclaving and filtration as suitable methods applicable to aqueous liquids, and dry heat for non-aqueous and dry sohd preparatiorrs. The choice is determined largely by the ability of the formulation and container to withstand the physical stresses apphed by moist heat... 

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