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Exhaustive alkylation

The lead alkyls and scavengers contained in fuels cause rapid poisoning ol exhaust gas catalytic converters. They are tolerated only in trace quantities in fuels for vehicles having that equipment. The officially allowed content is 0.013 g Pb/1, but the contents observed in actual practice are less than 0.005 g Pb/1. [Pg.208]

The potential advantages of LPG concern essentially the environmental aspects. LPG s are simple mixtures of 3- and 4-carbon-atom hydrocarbons with few contaminants (very low sulfur content). LPG s contain no noxious additives such as lead and their exhaust emissions have little or no toxicity because aromatics are absent. This type of fuel also benefits often enough from a lower taxation. In spite of that, the use of LPG motor fuel remains static in France, if not on a slightly downward trend. There are several reasons for this situation little interest from automobile manufacturers, reluctance on the part of automobile customers, competition in the refining industry for other uses of and fractions, (alkylation, etherification, direct addition into the gasoline pool). However, in 1993 this subject seems to have received more interest (Hublin et al., 1993). [Pg.230]

The reactivity of alkylthiazoles possessing a functional group linked to the side-chain is discussed here neither in detail nor exhaustively since it is analogous to that of classical aliphatic and aromatic compounds. These reactions are essentially of a synthetic nature. In fact, the cyclization methods discussed in Chapter II lead to thiazoles possessing functional groups on the alkyl chain if the aliphatic compounds to be cyclized, carrying the substituent on what will become the alkyl side chain, are available. If this is not the case, another functional substituent can be introduced on the side-chain by cyclization and can then be converted to the desired substituent by a classical reaction. [Pg.340]

The first kinetic results in the area were obtained by studying the quatemization of 4-alkyl-, 5-alkyT, and 2-alkylthiazoles with methyl iodide (253-255). A deeper and more exhaustive study of this reaction has been carried out recently with more elaborate substrates (152). [Pg.386]

Salt formation with Brmnsted and Lewis acids and exhaustive alkylation to form quaternary ammonium cations are part of the rich derivati2ation chemistry of these amines. Carbamates and thiocarbamates are formed with CO2 and CS2, respectively the former precipitate from neat amine as carbamate salts but are highly water soluble. [Pg.208]

Dialkyldimethyl and alkyltrknethyl quaternaries can be prepared direcdy from secondary and primary amines as shown ia equations 7 and 8, respectively. This process, known as exhaustive alkylation, is usually not the method of choice on a commercial scale. This technique requires the continuous addition of basic material over the course of the reaction to prevent the formation of amine salts (223,224). Furthermore, products such as inorganic salt and water must be removed from the quaternary. The salt represents a significant disposal problem. [Pg.381]

Paint and varnish manufacturing Resin manufacturing closed reaction vessel Varnish cooldng-open or closed vessels Solvent thinning Acrolein, other aldehydes and fatty acids (odors), phthalic anhydride (sublimed) Ketones, fatty acids, formic acids, acetic acid, glycerine, acrolein, other aldehydes, phenols and terpenes from tall oils, hydrogen sulfide, alkyl sulfide, butyl mercaptan, and thiofen (odors) Olefins, branched-chain aromatics and ketones (odors), solvents Exhaust systems with scrubbers and fume burners Exhaust system with scrubbers and fume burners close-fitting hoods required for open kettles Exhaust system with fume burners... [Pg.2177]

Ribosomal protein L12 was oxidized with 0.3 M H202 at 30°C for 1 h. After dialysis, the protein was incubated in the presence of 0.8 M 2-mercaptoethanol for 48 min at 37 °C and dialyzed. The amount of methionine residues was quantitated by exhaustive alkylation of the protein with [14C]iodoacetic acid. [Pg.857]

A major disadvantage of CVD (as opposed to PVD) is that many precursors are toxic and in some cases lethal even at low concentration (for instance nickel carbonyl, diborane, arsine, and phosphine). Some are also pyrophoric, such as silane, some alkyls, arsine, and phosphine. Very often the reaction is not complete and some of the precursor materials may reach the exhaust unreacted. In addition, many of the by-products of the reaction are also toxic and corrosive. This means that all these effluents must be eliminated or neutralized before they are released to the... [Pg.124]

When it is desired to convert a primary or secondary amine directly to the quaternary salt exhaustive alkylation), the rate can be increased by the addition of a nonnucleo-philic strong base that serves to remove the proton from RR NH2 or RR R"NH and thus liberates the amine to attack another molecule of RX. ... [Pg.500]

Fischer s base, a typical starting material, is commercially available and is also obtained in situ from the corresponding quaternary salt, substituted indolines 4 can be prepared by TV-alkylation of 2,3,3-trimethyl-3//-indole followed by alkali treatment, or by exhaustive alkylation of 2,3-dimethylindole (N- and C-alkylation) followed by alkali treatment (Scheme 3). Further, methylation of indoline 5 with methyl iodide leads to C-methylation on the methylene group or the Plancher rearrange-... [Pg.5]

Cotton grafted with 2-vinylpyridine followed by quaternisation using an excess of an alkyl bromide or epichlorohydrin showed markedly increased exhaustion with direct dyes [399]. Grafting alone gave a substantial effect, with further slight improvements being conferred by the quaternisation. Improved fastness to washing was also claimed. [Pg.208]

Quantitative assessment of the electrophilic character of various types of phosphenium ions has been attempted using computational studies on hydride and halide exchange reactions, and the results attribute to 1,3,2-diazaphospholenium ions a lower electrophilicity (and thus higher stability) than other types of phosphenium ions [20, 66], The gain in stability due to aromatic -delocalization is predicted to be somewhat larger than inductive stabilization resulting from exhaustive A-alkylation of the parent diaminophosphenium ion, [P(NH2)2]+. [Pg.84]

It is the purpose of this chapter to summarize what is currently known about the stereochemistry and conformation of organogermanium, tin and lead compounds. Coverage is selective rather than exhaustive. The first section deals with compounds in which substitution by four different groups causes the metal atom to be stereogenic. We have limited our discussion to those cases in which at least three of the four substituents are alkyl or aryl. In this section we also briefly discuss pentacoordinated triorgano halostannanes. [Pg.196]

Of course, the high reactivity of the Grignard reagents can be used to good advantage for exhaustive alkylation or arylation in the preparation of a wide range of phosphorus halides and esters.43 18... [Pg.119]

The method described in this preparation of mesitoic acid avoids the preparation of bromomesitylene,13 and the yield of acid is essentially the same as that from the two-step synthesis.2-13 This procedure appears to be general and can be used to prepare such acids as a- and /3-naphthoic acids,14 cumenecarboxylic acid, 2,5-dimethylbcnzoic acid, and durenecarboxylic acid. Carboxylic acids could not be obtained from benzothiophene, vera-trole, -dimethoxybenzene, and ferrocene under the conditions of this reaction. Although there has been no exhaustive study, this procedure is probably applicable to a variety of aromatic compounds, especially alkylated aromatics. Aromatic compounds which readily undergo oxidation, e.g., ferrocene, catechol, and hydroquinone, do not lend themselves to this method. [Pg.106]

Solvent co-catalysis. It will be noticed that all but one of the reactions quoted on p.147 take place in an alkyl halide solvent. A list of most of the reactions belonging to this class is given in Table 1 (which, however, is not claimed to be exhaustive). Pepper [47] first suggested that alkyl halides could act as co-catalysts by a reaction which can be represented generally as... [Pg.123]

The list of termination and transfer reactions given here is certainly not exhaustive. Furthermore, it must be remembered that hydrocarbons under the influence of metal halides may undergo alkylation and isomerization reactions, and conjunct polymerizations [24], especially if the temperature is much above 0°. It is therefore of the greatest importance that in future the simplest systems should be selected for investigation, and that the nature of the reaction products be examined with particular care. [Pg.252]

HZ Sommer, HI Lipp, LL Jackson. Alkylation of amines. A general exhaustive alkylation method for the synthesis of quaternary ammonium compounds, (effects of hindrance) J Org Chem 36, 824, 1971. [Pg.270]

A very similar reagent is benzyl t-butyl imidodicarboxy late 27, which is prepared from benzyl alcohol and benzoyl isocyanate, followed by exhaustive acylation with t-butoxycarbonyl chloride. Aminolysis of the resulting triacylamine yields 27. Treatment of the sodium salt of compound 27 with alkyl halides, followed by hydrolysis, gives primary amines53. [Pg.542]


See other pages where Exhaustive alkylation is mentioned: [Pg.38]    [Pg.353]    [Pg.208]    [Pg.135]    [Pg.249]    [Pg.180]    [Pg.347]    [Pg.337]    [Pg.185]    [Pg.855]    [Pg.37]    [Pg.713]    [Pg.107]    [Pg.855]    [Pg.54]    [Pg.115]    [Pg.35]    [Pg.108]    [Pg.221]    [Pg.85]    [Pg.17]    [Pg.899]    [Pg.521]    [Pg.152]    [Pg.276]    [Pg.495]    [Pg.25]   
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See also in sourсe #XX -- [ Pg.892 ]

See also in sourсe #XX -- [ Pg.1103 ]




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Exhaustive alkylation synthesis

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