UUmann reaction


Stephen reaction Stobbe condensation UUmann reaction Willgerodt reaction.  [c.1211]

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification.  [c.159]

There are many compounds in existence which have a considerable positive enthalpy of formation. They are not made by direct union of the constituent elements in their standard states, but by some process in which the necessary energy is provided indirectly. Many known covalent hydrides (Chapter 5) are made by indirect methods (for example from other hydrides) or by supplying energy (in the form of heat or an electric discharge) to the direct reaction to dissociate the hydrogen molecules and also possibly vaporise the other element. Other known endothermic compounds include nitrogen oxide and ethyne (acetylene) all these compounds have considerable kinetic stability.  [c.77]

In the sucrose molecule, union takes place through carbon atom 1 of the glucose molecule and carbon atom 2 of the fructose molecule hence sucrose is a nonreducing sugar, since neither the potential aldehyde nor the potential ketone grouping is now available for reaction. If glucose is represented as G-r, where r is the potential aldehyde group, and fructose as F r, where r is the potential ketone group, then the sucrose molecule may be conveniently remembered as G-r-r-F, indicating clearly that both the reducing groups are concerned in the union of the tw o monosaccharide residues.  [c.136]

In the following preparation, this reaction is exemplified by the union of anthracene with maleic anhydride, to form 9,io-dihydroanthracene-9,io-e do-a -succinic anhydride note that as a result of this reaction both the outer rings of the anthracene system become truly aromatic in character.  [c.292]

In the sucrose molecule, union takes place through carbon atom 1 of the glucose molecule and carbon atom 2 of the fructose molecule hence sucrose is a nonreducing sugar, since neither the potential aldehyde nor the potential ketone grouping is now available for reaction. If glucose is represented as G-r, where r is the potential aldehyde group, and fructose as K r, where r is the potential ketone group, then the sucrose molecule may be conveniently remembered as G-r-r-F, indicating clearly that both the reducing groups are concerned in the union of the two monosaccharide residues.  [c.136]

An example of a commercial semibatch polymerization process is the early Union Carbide process for Dynel, one of the first flame-retardant modacryhc fibers (23,24). Dynel, a staple fiber that was wet spun from acetone, was introduced in 1951. The polymer is made up of 40% acrylonitrile and 60% vinyl chloride. The reactivity ratios for this monomer pair are 3.7 and 0.074 for acrylonitrile and vinyl chloride in solution at 60°C. Thus acrylonitrile is much more reactive than vinyl chloride in this copolymerization. In addition, vinyl chloride is a strong chain-transfer agent. To make the Dynel composition of 60% vinyl chloride, the monomer composition must be maintained at 82% vinyl chloride. Since acrylonitrile is consumed much more rapidly than vinyl chloride, if no control is exercised over the monomer composition, the acrylonitrile content of the monomer decreases to approximately 1% after only 25% conversion. The low acrylonitrile content of the monomer required for this process introduces yet another problem. That is, with an acrylonitrile weight fraction of only 0.18 in the unreacted monomer mixture, the low concentration of acrylonitrile becomes a rate-limiting reaction step. Therefore, the overall rate of chain growth is low and under normal conditions, with chain transfer and radical recombination, the molecular weight of the polymer is very low.  [c.279]

The low rate of copolymerization and tendency for low molecular weight polymer are overcome by using emulsion polymerization. The rate of polymerization and polymer molecular weight are then controlled by varying the rate of initiation and the surfactant concentration. The copolymer composition is controlled by adding acrylonitrile monomer to the reactor at a rate that maintains a constant pressure of - 520 kPa (75 to 76 psi) at 40°C. This pressure is produced by a free-monomer phase consisting of 18% acrylonitrile. Thus as long as there is a free-monomer phase the 18% acrylonitrile level can be maintained by hoi ding the reaction pressure constant at 520 kPa (76 psi). The Union Carbide process requires 77 hours and 19 additions of acrylonitrile. The yield of copolymer is 65.8% and the final vinyl chloride content of the polymer is 60.5%.  [c.279]

Oxygen reacts with all other elements except the light, rare gases helium, neon, and argon (13). The reactants usually must be activated by heating before the reaction proceeds at appreciable rates, and if the final union releases more than enough energy to activate subsequent portions of both reactants, the overall process may be self-sustaining. The process is known as combustion when light and heat are evolved. For certain elements, such as the alkaU metals mbidium and cesium, activation energy provided at room temperatures is sufficient, and chemical reactions become spontaneous upon contact. Other metals such as finely powdered iron and nickel may be made pyrophoric by careful preparation and reduction of surface oxides. These then ignite spontaneously upon contact with the oxygen in air and continue to react with the evolution of light and heat. Such reactions may be explosive.  [c.476]

Prior to 1975, reaction of mixed butenes with syn gas required high temperatures (160—180°C) and high pressures 20—40 MPa (3000—6000 psi), in the presence of a cobalt catalyst system, to produce / -valeraldehyde and 2-methylbutyraldehyde. Even after commercialization of the low pressure 0x0 process in 1975, a practical process was not available for amyl alcohols because of low hydroformylation rates of internal bonds of isomeric butenes (91,94). More recent developments in catalysts have made low pressure 0x0 process technology commercially viable for production of low cost / -valeraldehyde, 2-methylbutyraldehyde, and isovaleraldehyde, and the corresponding alcohols in pure form. The producers are Union Carbide Chemicals and Plastic Company Inc., BASF, Hoechst AG, and BP Chemicals.  [c.374]

Advanced Cracking Techniques. Technologies were developed to pyrolyze whole cmde oil or various heavy petroleum fractions. These methods have in common very high temperatures, ultrashort residence times in the reactor zone, and rapid quench of the reaction products to minimize undesirable by-products. Among these techniques are the advanced cracking reactor from Union Carbide Corporation and thermal regenerative cracking from Gulf OH, and Stone and Webster Engineering Corporation (60). These technologies are capital intensive, however, and have never been commercialized.  [c.126]

Localized Reaction Phenomena. High temperature gasification of high ash content coals in a fluidized bed and the gas-phase production of linear low density polyethylene (LLDPE) are illustrative of the impacts of localized reaction phenomena. In high temperature coal gasification, particles may overheat and sinter. Successive contacting of coal with oxidizing and reducing atmospheres, a consequence of internal soflds circulation, may alter particle surfaces and affect kinetics (71). Union Carbide s UNIPOL fluid bed requires conditions for preventing agglomeration of the polymer and controlling the particle sizes in the fluidized bed (72). Agglomeration occurs wherever the fluid-bed temperature, particularly near the gas distributor, reaches the polymer melting point. Reaction heat must be uniformly generated and removed even during start-up, shutdown, and other transient operating conditions. In addition, equiUbrium particle size distributions must be estabflshed that balance the desire for low fluidizing gas rates and low concentrations of fine particles overhead against the need to maintain the high fines concentrations required for estabUshing fluid beds that are freely bubbling and the need to limit oversize particle production. For successflil reactor performance, nonfouling operation must be demonstrated in a unit that is sufficiently large to include these influences.  [c.520]

Because of its amphoteric nature, tin reacts with strong acids and strong bases but remains relatively resistant to neutral solutions. A thin oxide film forms on tin exposed to oxygen or dry air at ordinary temperatures heat accelerates this oxide formation. Tin is not attacked by gaseous ammonia even when heated. Chlorine, bromine, and iodine react with tin at normal temperatures, and fluorine reacts at 100°C, forming the appropriate stannic haUdes. Tin is easily attacked by hydrogen iodide and hydrogen bromide, but less readily by hydrogen chloride it is weaMy attacked by gaseous hydrogen fluoride, and it slowly dissolves in aqueous hydrochloric acid. Hot concentrated sulfuric acid reacts with tin, forming stannous sulfate, whereas dilute sulfuric acid reacts only slowly with tin at room temperature. Reaction of tin with dilute nitric acid yields soluble tin nitrates in concentrated nitric acid, tin is oxidized to insoluble hydrated stannic oxide. No reaction occurs upon direct union of tin with hydrogen, nitrogen, or carbon dioxide.  [c.64]

Modem plants manufacture chlorosulfuric acid by direct union of equimolar quantities of sulfur trioxide and dry hydrogen chloride gas. The reaction takes place spontaneously with evolution of a large quantity of heat. Heat removal is necessary to maintain the temperature at 50—80°C and thus minimize unwanted side reactions. The sulfur trioxide may be in the form of 100% Hquid or gas, as obtained from boiling oleum, ie, fuming sulfuric acid, or may be present as a dilute gaseous mixture as obtained direcdy from a contact sulfuric acid plant (24). The hydrogen chloride gas can be in the form of 100% gas or in a diluted form.  [c.86]

An alternative approach (78,79) is based on a set of possible reaction schemes that are used to generate potential new pathways. Under both approaches, the problem, in part, is how to evaluate the utiUty of a particular scheme. A computer-assisted approach to predicting potentially useful reactions has been developed (80). The union of existing capabiUties in modeling chemical stmctures with selecting reaction pathways has not yet taken place.  [c.64]

A system based partly on historical names, partly on the substrate, and partly on the type of reaction catalyzed is far from satisfactory. In 1956, the International Union of Biochemistry set up a Commission on Enzymes to consider the classification and nomenclature of enzymes. The Commission presented a report in 1961 whose recommendations for naming and classifying enzymes were subsequently adopted (12). Enzymes are classified on the basis of the reactions they catalyze. Despite its apparent complexities, the system is precise and very descriptive, accommodating existing enzymes and serving as a systematic basis for the naming of new enzymes. AH enzymes are placed in one of the six principal classes.  [c.289]

Process. Figure 3 shows a simplified flow diagram for the process previously employed by Union Carbide to produce ethanol by the direct hydration of ethylene (127). An ethylene-rich gas is combined with process water, heated to the desired reaction temperature, and passed through a fixed-bed catalytic reactor to form ethanol. The vapor leaving the reactor is slightly hotter than the feed because the reaction is exothermic. The reactor product is cooled by heat exchange with the reactor feed stream and is separated into Hquid and vapor streams. The Hquid stream goes to the ethanol refining system, and the vapor stream is scmbbed with water to remove ethanol. The washed gas, mostly unreacted ethylene, is enriched with fresh ethylene feed and recycled to the reactor. A small vent or purge stream is removed from the recycled ethylene to prevent buildup of unwanted impurities in the gas cycle.  [c.406]

Advanced Cracking Reactor. The selectivity to olefins is increased by reducing the residence time. This requires high temperature or reduction of the hydrocarbon partial pressure. An advanced cracking reactor (ACR) was developed jointly by Union Carbide with Kureha Chemical Industry and Chiyoda Chemical Constmction Co. (72). A schematic of this reactor is shown in Figure 6. The key to this process is high temperature, short residence time, and low hydrocarbon partial pressure. Superheated steam is used as the heat carrier to provide the heat of reaction. The burning of fuel  [c.442]

Ethylene oxide has been produced commercially by two basic routes the ethylene chlorohydrin and direct oxidation processes. The chlorohydrin process was first iatroduced dufing World War I ia Germany by Badische Anilin-und Soda-Eabfik (BASE) and others (95). The process iavolves the reaction of ethylene with hypochlorous acid followed by dehydrochlofination of the resulting chlorohydrin with lime to produce ethylene oxide and calcium chloride. Union Carbide Corp. was the first to commercialize this process ia the United States ia 1925. The chlorohydrin process is not economically competitive, and was quickly replaced by the direct oxidation process as the dominant technology. At the present time, all the ethylene oxide production ia the world is achieved by the direct oxidation process.  [c.454]

Tube sizes are 1 to 1.5 0 for exothermic reactions and up to 3 or 4 0 for endothermic reactions. Reactors with 3 0 made for an endothermic dehydrogenation in the synthetic rubber program during World War II were later used for exothermic hydrogenation at Union Carbide Corp. In the endothermic reaction, if a cool spot developed at the centerline in the reactor tubes, it cut catalyst utilization but no other loss was incurred. When it was used for exothermic reactions, a nickel catalyst of good quality and long life was deactivated much faster than expected. After more than 20 years of less than perfect performance a detailed thermal analysis and simulation revealed that only a short length of each tube was working and there was a overheating at the center. At the hot spot, catalyst deactivated gradually by organic deposits and solid structure changes, and the working zone moved down to where catalyst was not used (or misused) yet. In weeks, the working zone reached the bottom of the tube and production started dropping abruptly. Then catalyst in the reactor was regenerated by oxidation. During this time the large and reversible loss was converted to a small but permanent loss and production started again. After a few such periods the catalyst had to be changed.  [c.176]

C-Alkylation of pyrazoles was a rather uneommon reaction until Grandberg and Kost found the experimental conditions necessary to obtain high yields of 4-benzylpyrazoles (66AHC(6)347). With A-unsubstituted pyrazoles a large excess of aluminum ehloride is neeessary to aeeomplish alkylation at C-4.  [c.241]

In the following preparation, this reaction is exempliBed by the union of anthracene with maleic anhydride, to form 9,io-dihydroanthracene-9,io-v do-a -succinic anhydride note that as a result of this reaction both the outer rings of the anthracene system become truly aromatic in character.  [c.292]

Amides can be reduced to amines with LiAlH, although the reaction proceeds slower than the reduction of most other functional groups (W.A. Harrison, 1961 W.A. Ayer, 1968), which have to be re-oxidized afterwards if desired. Diborane is also useful and does not attack ester groups, but C—C double bonds (H.C. Brown, 1964). Sodium tetrahydroborate reduces amides only in the presence of acidic catalysts, e.g. CoCIj (prim, and sec. amides only T. Sa-toh, 1969) or carboxylic acids (N. Umino, 1976). Secondary and tertiary amides are O-alkylated with Meerwein s reagent (EtjO BF/), and the resulting carbenium ions are reduced in high yield with NaBH, in ethanol (R.F. Borch, 1968). In all these cases the C—N linkages remain intact after reduction. Cleavage into amines and alcohols (from the reduction of the acyl moiety) occurs only occasionally. Esters, in contrast, are almost always cleaved on reduction because alkoxide ions are easily cleaved from the intermediate hemiacetal anions. In amides the carbonyl oxygen bound to boron or aluminum is removed much more easily than an amide anion. Nitriles are converted into aldehydes by several reducing agents, e.g. DIBAL, complex hydrides, or catalytic hydrogenation (E. Winterfeldt, 1975),  [c.111]

Acetyl chlotide was formerly manufactured by the action of thionyl chlotide [7719-09-7], CI2OS, on gray acetate of lime, but this route has been largely supplanted by the reaction of sodium acetate or acetic acid and phosphoms ttichlotide [7719-12-2] (24). A similar route apparently is stiU being used in the Soviet Union (25). Both pathways ate inherently costly.  [c.81]

Anodes. Fluorine cell anodes are the most important cell component, and thek design and materials of constmction are key factors in determining productivity and cell life. Nickel and graphite, used in early cells, were abandoned when it was discovered that hard, nongraphitized carbon gave longer life. In the 1990s, anodes are made from petroleum coke and a pitch binder which is calcined at temperatures below that needed to convert the material to graphite. The anode carbon has low electrical resistance, high physical strength, and is resistant to reaction with fluorine. Historically, Union Carbide s YBD-grade carbon made the best anodes. More recently other carbon manufacturers have begun to offer improved anodes for fluorine service, eg, Carbone of America Ind. Corp. SocifitH Des Electrodes et Refractakes Savoifi, part of the Pechiney group and Toyo Tanso USA, Inc. The nature and quahty of the starting materials (petroleum coke and pitch) and careful control of the calcining process are generally responsible for the improvements (92).  [c.127]

Diethylene Glycol. Physical properties of diethylene glycol ate Hsted in Table 1. Diethylene glycol is similar in many respects to ethylene glycol, but contains an ether group. It was originally synthesi2ed at about the same time by both Lourenco and Wurt2 (63) in 1859, and was first marketed by Union Carbide in 1928. It is a coproduct (9—10%) of ethylene glycol produced by ethylene oxide hydrolysis. It can be made directly by the reaction of ethylene glycol with ethylene oxide, but this route is rarely used because more than an adequate supply is available from the hydrolysis reaction. The 1993  [c.362]

Following the discovery of polyethylene by ICI in the early 1930s, work went ahead first on the design of a pilot plant and then of a commercial plant, commissioned late in 1939, for the continuous production of polymer at a pressure of 150 MPa (22,000 psi) and a temperature of 170°C. Because the operating pressure was about four times that employed in the majority of the ammonia and methanol plants in use at the time the engineering problems in the design of the plant were considerable. Furthermore, process design proved difficult because of the need to remove the high heat of polymerization. By the mid-1940s a number of alternative processes had been designed by E. I. du Pont de Nemours Co., Inc. and Union Carbide in the United States and BASF in Germany. These processes all operated at high pressure but differed in the way in which the heat of polymerization was removed. ICI and Du Pont used stirred reactors, known as autoclaves, in which the heat of reaction was used to raise the temperature of the incoming stream of ethylene containing small quantities of initiator. Union Carbide and BASF developed tubular reactors in which the heat of polymerization is removed by coolant circulating through jackets surrounding the reactor.  [c.76]

The carbonyl functionahty of MIBK can be hydrogenated over nickel catalysts to yield methyl isobutyl carbinol (4-methyl-2-pentanol or methyl amyl alcohol) [108-11-2]. Industrial processes coproduce methyl isobutyl carbinol during the hydrogenation of mesityl oxide to MIBK. The product ratio of methyl isobutyl carbinol—MIBK during this reaction can be shifted toward methyl isobutyl carbinol by adopting a higher than normal pressure and H2 organic ratio (59). Methyl isobutyl carbinol is used as an ore flotation frother and to produce 2inc dialkyl dithiophosphate lube oil additives. It is produced in the United States by SheU and Union Carbide ( 1.12/kg, October 1994).  [c.490]

Union Carbide (now Advanced Ceramics Technologies) developed a process similar to CVD to produce pyrolytic boron nitride-shaped bodies. The process employs graphite mandrels in a high temperature, low pressure reaction chamber. Vapors deposit on the mandrel to produce a thick, high purity, anisotropic, impervious BN layer. In many cases, the desired product is simply sHpped off the cooled graphite mandrel. Increasingly, the desired product is not the free-standing pyrolytic BN object but a BN coating on a shaped graphite body. Graphite shapes having adherent BN coatings are used routinely for r-f susceptors, resistance heaters, heat shields, and no22les (see Ablative materials Refractory coatings).  [c.55]

The Unipol PP process (Union Carbide), extends technology originally developed for ethylene polymerization to propylene polymerization utilizing Shell (SHAC) catalysts. One large gas-phase fluidized-bed reactor is used for the production of homopolymer and random copolymer a second, smaller reactor is used to produce the mbber required for impact copolymers. The heat of reaction is removed by cooling the monomer recycle through an external heat exchanger (Fig. 12). The Novolen process (BASF), has been rejuvenated through the use of high yield catalyst technology. Problems associated with low polymer productivity, high levels of atactic polymer, and catalyst residues have been alleviated by the use of these catalysts. Amoco s horizontal stirred-bed gas-phase reactor is the heart of the Amoco /Chisso process. This reactor (Fig. 13) acts as a series of polymerization stages in a single reactor vessel, facihtating the production of broad molecular weight distribution homopolymers and random copolymers. Impact copolymers are produced in a second similar reactor in series as in other processes (135). MonteU produces specialty propylene copolymers in the multistage gas-phase CataHoy process (136).  [c.416]

The search for catalyst systems which could effect the 0x0 reaction under milder conditions and produce higher yields of the desired aldehyde resulted in processes utilizing rhodium. Oxo capacity built since the mid-1970s, both in the United States and elsewhere, has largely employed tertiary phosphine-modified rhodium catalysts. For example, over 50% of the world s butyraldehyde (qv) is produced by the LP Oxo process, technology Hcensed by Union Carbide Corporation and Davy Process Technology.  [c.465]

Ma.nufa.cture. Phosphoms trichloride is made by direct union of the elements. The reaction is moderated by combining the chlorine and phosphoms in the presence of a precharge of phosphoms trichloride that is refluxed continuously. A typical manufacturing scheme is shown in Figure 4. Liquid phosphoms and chlorine gas are continuously introduced into the reaction vessel, which is arranged so that a significant portion of the phosphoms trichloride contained in it undergoes reflux. The remaining phosphoms trichloride is distilled into a pot. A yield of ca 99.0% or higher of purified phosphoms trichloride usually is obtained with respect to both the phosphoms and chlorine. The effect of raw material impurities on reactor operations and process waste generations has been evaluated (42). Most raw material impurities remain in the reactor and are removed periodically. Process safety can be improved by using an on-line analy2er and other procedures (43—45). Monsanto has the world s largest production unit for PCl.  [c.367]

The first aromatic sulfone polymer produced commercially was introduced as Bakelite polysulfone but now is sold by Union Carbide under the trade name Udel. It is made by reaction of the disodium salt of bisphenol A (BPA) with 4,4 -dichIorodiphenyl sulfone in a mixed solvent of chlorobenzene and dimethyl sulfoxide (eq. 12).  [c.331]

Propane, 1-propanol, and heavy ends (the last are made by aldol condensation) are minor by-products of the hydroformylation step. A number of transition-metal carbonyls (qv), eg, Co, Fe, Ni, Rh, and Ir, have been used to cataly2e the oxo reaction, but cobalt and rhodium are the only economically practical choices. In the United States, Texas Eastman, Union Carbide, and Hoechst Celanese make 1-propanol by oxo technology (11). Texas Eastman, which had used conventional cobalt oxo technology with an HCo(CO)4 catalyst, switched to a phosphine-modified Rh catalyst ia 1989 (11) (see Oxo process). In Europe, 1-propanol is made by Hoechst AG and BASE AG (12).  [c.118]

Preparing sorbic acid by reaction of crotonaldehyde and acetone followed by oxidation of the crotonyUdenacetone is of interest in the former Soviet Union (41,42)  [c.283]

Aluminum Chloride-Based All lation. The eadier alkylation processes were variations of the Eriedel-Craft reaction on an aluminum chloride catalyst complex in a Hquid-phase reactor (27), including those developed by Dow Chemical, BASE, Monsanto, and Union Carbide in cooperation with Badger. The Union Carbide-Badger process was the one most widely used during the 1960s and 1970s, with 20 plants built worldwide.  [c.480]

In the manufacture of highly resident flexible foams and thermoset RIM elastomers, graft or polymer polyols are used. Graft polyols are dispersions of free-radical-polymerized mixtures of acrylonitrile and styrene partially grafted to a polyol. Polymer polyols are available from BASF, Dow, and Union Carbide. In situ polyaddition reaction of isocyanates with amines in a polyol substrate produces PHD (polyhamstoff dispersion) polyols, which are marketed by Bayer (21). In addition, blending of polyether polyols with diethanolamine, followed by reaction with TDI, also affords a urethane/urea dispersion. The polymer or PHD-type polyols increase the load bearing properties and stiffness of flexible foams. Interreactive dispersion polyols are also used in RIM appHcations where elastomers of high modulus, low thermal coefficient of expansion, and improved paintabiUty are needed.  [c.347]

In the mid-1970s, a process employing a rhodium complex catalyst, HRhCO[P(CgH3)2]2, was commercialized by Union Carbide. This technology (25,26), subsequently hcensed worldwide by Union Carbide and Davy McKee, operates at low temperatures 80—120°C and low pressure, 0.7—3 MPa (100—450 psi) and gives an isomer ratio of n- to isobutyraldehyde of 8 1 to 12 1. The advantages of the rhodium process for making butanals besides the lower temperatures and operating pressures, include a higher efficiency to the more valuable normal isomer and less by-product formation. The product butanals are separated continuously by vaporization from the nonvolatile catalyst, a distinct procedural advantage over the unmodified high pressure cobalt Oxo reaction. The latter requires a continuous separation and regeneration of the volatile cobalt hydrocarbonyl catalyst, which codistiUs with the butanal product. The rhodium catalyst, which is almost one thousand times more reactive than the cobalt hydrocarbonyl catalyst, requires relatively minute amounts of rhodium to achieve commercial rates of reaction.  [c.380]

Cationic Hydroxyethylcelluloses. These materials are manufactured by Union Carbide Corp. and National Starch and Chemical Corp., marketed under the trade names Polymer JR and Celquat, respectively (47,48). The cationic substituent on Polymer JR is presumably 2-hydroxypropyltrimethylammonium chloride (72). Celquat is presumably the reaction product of HEC with /V,/V-dia11y1-/V,/V-dimethy1ammonium chloride (73). Their primary appHcation is in shampoos and hair conditioners wherein the cationic moiety imparts substantivity to hair. Some typical properties of Celquat resins are given in Table 7.  [c.276]

The lithium is washed three times by transferring approximately 150-mL portions of anhydrous ethyl ether (Note 6) into the flask through the serum stopper by foroed siphoh through a stainless steel cannula, stirring the resulting suspension of lithium briefly, allowing the lithium to rise to the surface, and finally withdrawing the major part of the underlying ether by forced siphon through a cannula. Anhydrous ethyl ether (500 mL) is added to the resultant oil-free lithium. Methyl chloride gas (bp -24°C, d" 0.99 g/mL) from a compressed gas cylinder is passed through a flask containing 4A molecular sieves and Into a dry, 100-mL Pyrex graduated cylinder equipped with a 24/40 standard taper joint attached to a Claisen adapter and dry ice condenser, and cooled to -24°C with a bath of dry ice-acetone (Fig. 11. When 52.7 mL (52.5 g, 1.04 mol) of liquid methyl chloride has been collected, the adapter and condenser are removed, several boiling chips are added to the cold (-24°C) graduated cylinder, and the cylinder is stoppered with a rubber septum through which is inserted a stainless steel cannula. The other end of this cannula is inserted through the rubber septum of the flask so that its tip is just above the liquid surface of the reaction flask. Dry ice-acetone is then added to the condenser attached to the reaction flask. Vigorous stirring of the ethereal lithium dispersion is begun and the methyl chloride is added over approximately a 1.5-hr period. The rate at which methyl chloride is distilled into the reaction vessel is controlled by slight cooling or warming of the graduated cylinder which contains the liquid methyl chloride. During addition, the Initial grey suspension changes to a brown to purple suspension by the end of the addition, little if any lithium metal should be seen floating on the surface of the ether solution uhen stirring is interrupted. After the addition of methyl chloride is complete, the reaction mixture Is stirred at 25°C for an additional 0.5-1 hr and then allowed to stand overnight  [c.102]

Many of the methods discussed in this book stem from the practical experience of the author, who worked for 20 years at Union Carbide Corporation. Other experience came from consulting work for over 30 companies, and from the laboratory of Berty Reaction Engineers, Ltd. The corresponding theoretical treatments were developed while teaching six professional short courses and lecturing at the State University of New York at Buffalo, NY, The University of Akron, at Akron, OH, and as a Senior Fulbright Scholar at the Technical University of Munich, Germany. The final assembly of the book was started when the author again taught a short course at the University of Veszprem in Hungary after a 36 year interruption.  [c.280]


See pages that mention the term UUmann reaction : [c.163]    [c.532]    [c.460]    [c.225]    [c.337]    [c.365]    [c.176]    [c.177]   
Textbook on organic chemistry (1974) -- [ c.524 , c.527 ]