Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Oxonium

H3O" is strictly the oxonium ion actually, in aqueous solutions of acid this and Other solvated-proton structures exist, but they are conveniently represented as... [Pg.85]

Oxonium salt formation. Shake up 0 5 ml. of ether with 1 ml. of cone. HCl and note that a clear solution is obtained owing to the formation of a water-soluble oxonium salt. Note that aromatic and aliphatic hydrocarbons do not behave in this way. In general diaryl ethers and alkyl aryl ethers are also insoluble in cone. HCl. [Pg.396]

It should be noted that the Friedel-Crafts acylation differs from the Friedel-Crafts alkylation (compare Sections IV,3-4 and discussion preceding Section IV,1) in one important respect. The alkylation requires catal3d.ic quantities of aluminium chloride, but for acylation a molecular equivalent of aluminium chloride is necessary for each carbonyl group present in the acylating agent. This is because aluminium chloride is capable of forming rather stable complexes with the carbonyl group these complexes probably possess an oxonium... [Pg.725]

It is probable that, in general, acylation also occurs by the oxonium complex ... [Pg.726]

Many oxygen-containing compounds dissolve because of the formation of oxonium salts the latter are readily decomposed (hydrolysed) by pouring the acid into ice water. [Pg.1050]

The results of aetivatioii of aeyl cations led to our study of other carboxonium ions. Carboxonium ions are highly stabilized compared to alkyl cations. As their name indicates, they have both carbocationic and oxonium ion nature. [Pg.195]

Similar to oxonium ions, our studies of sulfonium ions also showed protosolvolytic activation in superacids to give sulfur superelectrophiles. The parent sulfonium ion (HjS ), for example, gives H4S (diprotonated hydrogen sulfide) in superacids. [Pg.197]

That some modification to the position so far described might be necessary was indicated by some experiments of Nesmeyanov and his co-workers. Amongst other compounds they nitrated phenyl trimethyl ammonium and triphenyloxonium tetrafluoroborates with mixed acid the former gave 96 % of m- and 4 % of -nitro compound (88 % total yield), whilst the latter gave 80% of the tri-(p-nitrophenyl)oxonium salt. Ridd and his co-workers have made a quantitative study of the phenyl trimethyl ammonium ion. Their results, and those of other recent workers on the nitration of several cations, are collected in table 9.3. [Pg.168]

The systematic name for the conjugate acid of water (HjO" ) is oxonium ion Its com mon name is hydronium ion... [Pg.34]

We can extend the general principles of electrophilic addition to acid catalyzed hydration In the first step of the mechanism shown m Figure 6 9 proton transfer to 2 methylpropene forms tert butyl cation This is followed m step 2 by reaction of the car bocation with a molecule of water acting as a nucleophile The aUcyloxomum ion formed m this step is simply the conjugate acid of tert butyl alcohol Deprotonation of the alkyl oxonium ion m step 3 yields the alcohol and regenerates the acid catalyst... [Pg.247]

With secondary and tertiary alcohols Ihis slage is an 8 1 reaclion m which Ihe alkyl oxonium ion dissociates to a carbocalion and water... [Pg.354]

Step 1 Proton transfer to the oxygen of the epoxide to give an oxonium ion... [Pg.682]

Step 2 Nucleophilic attack by water on carbon of the oxonium ion The carbon-oxygen bond of the ring is broken in this step and the ring opens... [Pg.682]

Step 3 The oxonium ion formed m step 2 loses a proton to give the tetrahedral intermediate m its neutral form This step concludes the first stage m the mechanism... [Pg.812]

Step 3 Deprotonation of the oxonium ion to give the neutral form of the tetrahedral intermediate... [Pg.850]

Protonation of the carbonyl oxygen as emphasized earlier makes the carbonyl group more susceptible to nucleophilic attack A water molecule adds to the carbonyl group of the protonated ester m step 2 Loss of a proton from the resulting oxonium ion gives the neutral form of the tetrahedral intermediate m step 3 and completes the first stage of the mechanism... [Pg.851]

Once formed the tetrahedral intermediate can revert to starting materials by merely reversing the reactions that formed it or it can continue onward to products In the sec ond stage of ester hydrolysis the tetrahedral intermediate dissociates to an alcohol and a carboxylic acid In step 4 of Figure 20 4 protonation of the tetrahedral intermediate at Its alkoxy oxygen gives a new oxonium ion which loses a molecule of alcohol m step 5 Along with the alcohol the protonated form of the carboxylic acid arises by dissocia tion of the tetrahedral intermediate Its deprotonation m step 6 completes the process... [Pg.851]

Step 3 Deprotonation of oxonium ion to give neutral form of tetrahedral intermediate OH OH... [Pg.1238]

Oxonium ion (Section 1 13) The species H30" (also called hydronium ion)... [Pg.1290]

Polyatomic Cations. Polyatomic cations derived by addition of more protons than required to give a neutral unit to polyatomic anions are named by adding the ending -onium to the root of the name of the anion element for example, PH4, phosphonium ion HjU, iodonium ion H3O+, oxonium ion CH3OHJ, methyl oxonium ion. [Pg.218]

The main contributing resonance forms include the oxonium (7), carbonium (8), and ammonium stmctures (9) ... [Pg.399]

Trifluoromethanesulfonic acid is miscible in all proportions with water and is soluble in many polar organic solvents such as dimethylformamide, dimethyl sulfoxide, and acetonitrile. In addition, it is soluble in alcohols, ketones, ethers, and esters, but these generally are not suitably inert solvents. The acid reacts with ethyl ether to give a colorless, Hquid oxonium complex, which on further heating gives the ethyl ester and ethylene. Reaction with ethanol gives the ester, but in addition dehydration and ether formation occurs. [Pg.315]

Cocatalysts of two types occur (/) proton-donor substances, such as hydroxy compounds and proton acids, and (2) cation-forming substances (other than proton), including alkyl and acyl haUdes which form carbocations and other donor substances leading to oxonium, sulfonium, halonium, etc, complexes. [Pg.564]


See other pages where Oxonium is mentioned: [Pg.160]    [Pg.287]    [Pg.293]    [Pg.293]    [Pg.349]    [Pg.379]    [Pg.726]    [Pg.1048]    [Pg.1050]    [Pg.103]    [Pg.195]    [Pg.176]    [Pg.154]    [Pg.160]    [Pg.354]    [Pg.18]    [Pg.65]   
See also in sourсe #XX -- [ Pg.262 ]

See also in sourсe #XX -- [ Pg.588 ]

See also in sourсe #XX -- [ Pg.177 , Pg.182 ]

See also in sourсe #XX -- [ Pg.626 ]

See also in sourсe #XX -- [ Pg.306 ]

See also in sourсe #XX -- [ Pg.177 , Pg.182 ]

See also in sourсe #XX -- [ Pg.5 ]

See also in sourсe #XX -- [ Pg.273 ]

See also in sourсe #XX -- [ Pg.71 , Pg.105 , Pg.309 ]

See also in sourсe #XX -- [ Pg.23 ]

See also in sourсe #XX -- [ Pg.232 ]

See also in sourсe #XX -- [ Pg.23 ]




SEARCH



1- methyl]oxonium salts

1.3- Carbenium-oxonium dications

A4-Oxocene, 2,8-disubstituted via cyclization of oxonium ions

Active centre oxonium

Active oxonium

Alcohols oxonium ion formation

Alkyl halides, oxonium salts and related compounds

Alkyl-aluminumsilyl oxonium ions

Alkyl-aluminumsilyl oxonium ions formation

Alkyl-aluminumsilyl oxonium ions theoretical calculations

Alkyl-aluminumsilyl oxonium ions zeolite

Alkylation, by oxonium salts

Allyl oxonium intermediate

Allylic oxonium ylides

Anhydrous materials oxonium perchlorate, acid phosphates, arsenates, sulphates and selenates

Blue oxonium ions

Boron trifluoride oxonium salts preparation

Carbenium-oxonium dication

Carbenium-oxonium ion equilibria

Carbocations on surfaces aluminumsilyl oxonium ion

Carbocations oxonium ions

Carotenoid oxonium ions

Complex oxonium

Crown ethers oxonium ion binding

Cyclic oxonium

Cyclic oxonium intermediate

Ethers reaction with oxonium salts

Fragmentation of Cyclic Oxonium Intermediates

Functionalization oxonium

Hydride transfer to cyclic oxonium ion

Intermediates oxonium

J Alkylation of 2-Hydrophosphinic Acids and Esters with Oxonium Salts

Metals Oxonium ions

Oxonium 2,3]-shift

Oxonium Rydberg radical

Oxonium allyl ether rearrangements

Oxonium and ammonium ion-exchange

Oxonium cation

Oxonium cation, Silyl

Oxonium centres

Oxonium compounds

Oxonium compounds, triethyloxo

Oxonium compounds, trimethyloxo

Oxonium concerted mechanism

Oxonium cyclic ether

Oxonium cyclopropanation

Oxonium dication

Oxonium dimerization

Oxonium exchange reaction

Oxonium fluoroborates

Oxonium fluoroborates Pyrylium salts

Oxonium fluoroborates Trialkyloxonium

Oxonium fluoroborates Trialkyloxonium salts

Oxonium fluoroborates s. Trialkyloxonium

Oxonium from cyclic acetals

Oxonium hexachloroantimonate, O-acetyldiethylFriedel-Crafts reaction

Oxonium hydroxide

Oxonium intramolecular

Oxonium ion

Oxonium ion crown ether complexes

Oxonium ion equilibria

Oxonium ion intermediate

Oxonium ion pair

Oxonium ion salts

Oxonium ions acidity

Oxonium ions arenes

Oxonium ions bicyclo

Oxonium ions chiral

Oxonium ions cleavage

Oxonium ions formation

Oxonium ions halides

Oxonium ions initiators

Oxonium ions long-lived

Oxonium ions phenols

Oxonium ions polyene cyclization

Oxonium ions primary

Oxonium ions reaction

Oxonium ions reaction with enol silanes

Oxonium ions reduction

Oxonium ions secondary

Oxonium ions silicon-stabilized

Oxonium ions superelectrophiles

Oxonium ions superelectrophilic

Oxonium ions tertiary

Oxonium ions trifluoromethyl

Oxonium ions, mass spectra

Oxonium ions, nucleophilic attack

Oxonium ions, ring opening

Oxonium ions, secondary equilibria

Oxonium ions, secondary preparation

Oxonium ions, secondary stability

Oxonium ions, secondary structure

Oxonium ions, secondary tertiary

Oxonium ions, stereoselective

Oxonium ions, stereoselective glycosylations with

Oxonium nitrates

Oxonium perchlorates

Oxonium polymerization

Oxonium rearrangement

Oxonium salt leaving groups

Oxonium salts

Oxonium salts, acyl-, preparation

Oxonium salts, alkylation

Oxonium salts, cleavage

Oxonium salts, cyclic

Oxonium special

Oxonium species

Oxonium stereoselectivity

Oxonium structure

Oxonium systems

Oxonium tetrafluoroborates

Oxonium ylide

Oxonium ylide -rearrangement

Oxonium ylide -rearrangements transition states

Oxonium ylide -shifts

Oxonium ylide 1,2]-Stevens rearrangement

Oxonium ylide approach

Oxonium ylide formation

Oxonium ylide mechanism

Oxonium ylides

Oxonium ylides Stevens -shift

Oxonium ylides cyclic

Oxonium ylides, formation

Oxonium ylides, rearrangement

Oxonium, triethyl-, tetrafluoroborate

Oxonium, trimethyl-, tetrafluoroborate

Pyridine-1-oxonium chloride, reaction

Reaction of ethers and oxonium salts with nitrogen compounds

Reaction with preformed trialkyl oxonium salts

Rearrangement, of: (cont oxonium ylides

Sulfoxide, Ammonium, and Oxonium Ylide Rearrangements

Transition state oxonium ion dissociation

Triethyl oxonium borontrifluoride

Ylide oxonium from carbenes

© 2024 chempedia.info