Sodium deactivation

The sodium in the E-cat is the sum of sodium added with the feed and sodium on the fresh catalyst. A number of catalyst suppliers report sodium as soda (Na20). Sodium deactivates the catalyst acid sites and causes collapse of the zeolite crystal structure. Sodium can also reduce the gasoline octane, as discussed earlier. 

Sodium Deactivation of Fluid Catalytic Cracking Catalyst... 

Sodium deactivates FCC catalysts by three separate mechanisms poisoning of acid sites, enhancing the sintering of matrix, and accelerating the destruction of... 

The yield of hydrocarbons (14.4%) were higher than that of equilibrium conversion of COj to methanol (ca 7% at 4001C, 50 atm). It means that methanol formation was accelerated by MTG reaction. When methanol synthesis catalyst was prepared by coprecipitation, the yield of hydrocarbons decreased (Run 2). This seems to be due to the deactivation of zeolite by the sodium remaining after 5 times wash. Similar tendency was observed on the hydrocarbon synthesis between two Cu-Zn/HY composite catalyst, in which one Cu-Zn catalyst was precipitated by Na2C03, and another Cu-Zn catalyst was precipitated by oxalic acid[3]. When methanol synthesis catalyst was prepared by sodium compound, remaining sodium deactivate an active site of zeolite on MTG reaction. 

The 3 Pi/2, 3 P2/2 excited states involved in the sodium D lines are the lowest energy excited states of the atom. Consequently, in a discharge in the vapour at a pressure that is sufficiently high for collisional deactivation of excited states to occur readily, a majority of atoms find themselves in these states before emission of radiation has taken place. Therefore... 

The earhest frothing process developed was the Dunlop process, which made use of chemical gelling agents, eg, sodium fluorosiUcate, to coagulate the mbber particles and deactivate the soaps. The Talalay process, developed later, employs freeze-coagulation of the mbber followed by deactivation of the soaps with carbon dioxide. The basic processes and a multitude of improvements are discussed extensively in Reference 3. A discussion more oriented to current use of these processes is given in Reference 115. 

Polybutene resins. These liquid resins are obtained by cationic polymerization of petroleum C4 streams in the presence of AICI3 at relatively low temperature. Temperature and AICI3 concentration are important factors as they influence the molecular weight and viscosity of the final resin. After reaction, the mixture is deactivated with water, methanol, ammonia or aqueous sodium hydroxide. The organic layer is separated and distilled to remove solvent and unconverted material. 

Ozone is more effective than chlorine in deactivating poliovirus, Cryptosporidium parvum, Giardia lamblia, and other protozoa. It also improves the color, taste, and odor of water dramatically. However, since no residual amount remains, it is always necessary to add a small amount of a more stable disinfectant as well (sodium hypochlorite, chlorine dioxide, etc.). 

Atotalof 6.2gof 17 -acetoxyandrosta-4,6-dien-3-one-[2a,la-c]-A -pyrazoline is added portionwise to a solution consisting of 2.4 ml of perchloric acid (70%) in 240 ml acetone. The reaction mixture is then poured into ice water and extracted with methylene dichloride. The organic layer is washed to neutrality with water, dried over anhydrous sodium sulfate and taken to dryness. The residue is chromatographed on 300 g silica gel (deactivated with water 10% v/w) and eluted with methylene dichloride to yield 3.32 g (58%) of 17 -acetoxy-la,2cc-methyleneandrosta-4,6-dien-3-one mp 178-179° (from diisopropyl ether) [aj 188°(CHCl3) 281 mfi (e20,700). Further... 

For many proteins, a simple buffer such as 0.1M phosphate, pH 7, produces excellent separations on SynChropak GPC columns. Generally, minimal interaction is achieved when the ionic strength is 0.05-0.2 M. To prevent denatur-ation or deactivation of proteins, the pH is generally kept near neutrality. For denatured proteins, 0.1% sodium dodecyl sulfate (SDS) in 0.1 M sodium phosphate, pH 7, is recommended. 

The ease of reaction of halopyridazines is indicated by the exothermic nature of the reaction of 3,6-dichloropyridazine with sodium methoxide at room temperature to yield 3-chloro-6-methoxy-pyridazine. Displacement of the deactivated chloro group in the latter required heating (66°, < 8 hr) the reaction mixture. Competitive methoxy-dechlorination (20°, 12 hr) of 3,4,6-trichloropyridazine shows the superior reactivity of the 4-position the 3,6-dichloro-4-methoxy analog (296) was isolated in high yield. The greater reactivity of the... 

Deactivation of zeolite catalysts occurs due to coke formation and to poisoning by heavy metals. In general, there are two types of catalyst deactivation that occur in a FCC system, reversible and irreversible. Reversible deactivation occurs due to coke deposition. This is reversed by burning coke in the regenerator. Irreversible deactivation results as a combination of four separate but interrelated mechanisms zeolite dealu-mination, zeolite decomposition, matrix surface collapse, and contamination by metals such as vanadium and sodium. 

Polyether sulfones can be prepared by the reaction of the sodium or potassium salt of bisphenol A and 4,4-dichlorodiphenyl sulfone. Bisphenol A acts as a nucleophile in the presence of the deactivated aromatic ring of the dichlorophenylsulfone. The reaction may also be catalyzed with Friedel-Crafts catalysts the dichlorophenyl sulfone acts as an electrophile ... 

The activity of catalyst degrades with time. The loss of activity is primarily due to impurities in the FCC feed, such as nickel, vanadium, and sodium, and to thermal and hydrothermal deactivation mechanisms. To maintain the desired activity, fresh catalyst is continually added to the unit. Fresh catalyst is stored in a fresh catalyst hopper and, in most units, is added automatically to the regenerator via a catalyst loader. 

Alkaline earth metals in general, and sodium in particular, are detrimental to the FCC catalyst. Sodium permanently deactivates the catalyst by neutralizing its acid sites. In the regenerator it causes the zeolite to collapse, particularly in the presence of vanadium. Sodium comes from two prime sources ... 

Sodium plays an intrinsic part in the manufacturing of FCC catalysts. Its detrimental effects are well known and, because it deactivates the... 

Vanadium and sodium neutralize catalyst acid sites and can cause collapse of the zeolite structure. Figure 10-5 shows the deactivation of the catalyst activity as a function of vanadium concentration. Destruction of the zeolite by vanadium takes place in the regenerator where the combination of oxygen, steam, and high temperature forms vanadic acid according to the following equations ... 

The oxidation of 3-benzothiepin to its S -oxide 9 (R = H) was unsuccessful with 3-chloroper-oxybenzoic acid or sodium periodate.68 Also, the route which uses the formation of the di-bromosulfuranes 8, known to be sensitive to hydrolysis (vide infra), was ultimately unsuccessful because 8 is only available if the C — C double bonds of the thiepin ring are deactivated towards bromine addition by ester substituents (R = C02Me), concurrently providing the compound with stability towards hydrolysis.65... 

Vanadate (sodium orthovanadate or peroxovanadate) exhibits insulin-like effects in vitro (activation of insulin receptor tyrosine kinase, PI 3-kinase, Akt) and in vivo (diabetic rats, humans). These effects can be explained at least in part by the inhibition of phosphotyrosine phosphatases which deactivate the INSR tyrosine kinase. 

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