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Acetylides—

Acetylides are salts of acetylene, which is, under normal conditions, a gas with a slightly acidic character (p/sTa is 25, for comparison pZa of acetic acid is 4.76). Due to their acidic nature, one or both of the hydrogen atoms can be substituted by a metal atom. Furthermore, acetylene forms so-called metallo-addition compounds usually containing the acetylene molecule and an added metal compound (CjHrMX) [1]. [Pg.303]

The acetylides of alkali metals and salts of alkaline earths are reactive compounds, which violently decompose in contact with water or even in contact with moisture in the air, releasing acetylene. These acetylides do not have the characteristics of primary explosives and are widely used in organic synthesis as a source of the acetylene (ethyn-l,2-diyl) group. [Pg.303]

Acetylides of heavy metals (silver, copper, gold, mercury) do not react with moisture and are stable in contact with air. These acetylides are very sensitive to mechanical stimuli and have the characteristics of primary explosives. Their explosive power is considered to be the same as that of azides and fulminates [2]. [Pg.303]

Under certain circumstances acetylene combines with the metals copper, silver and mercury to form acetylides. As a dry substance these acetylene compounds are explosive and ignite through impact or friction. Compared to the other acetylides, silver acetylide releases the largest amount of energy in an explosion. Acetylides can originate and precipitate from watery saline solutions of the metals mentioned above under certain conditions regarding temperature, pH value and concentration. These precipitation reactions were previously used in the wet chemical acetylene analytics. [Pg.244]

In acetylene engineering - and especially in the generation of acetylene from carbide as well as in supply engineering - the possibihty of generating acetylide is an important factor when selecting the material for the equipment. The formation of acetylides is not only possible in saline solutions in laboratory experiments but it also occurs when moist crude acetylene comes into contact with metallic silver or copper surfaces. Corrosion products encourage acetylide formation on copper surfaces. [Pg.245]

Tests have shown that there is considerable acetylide formation when pure copper or copper alloys (brass) have a Cu-content 70%. The layer thicknesses can reach a strength that allows the separation of pure acetylide as particles, similar to scale. With Cu contents of 70% and below, very thin acetylide layers are still possible but there is no danger of ignition. [Pg.245]


Metal derivatives of terminal alkynes, RC2H. Transition metals form complex acetylides (e.g. (M(C = CR) ]- ) often containing the metal in low oxidation states. [Pg.12]

Metallic Derivatives, (a) Cuprous Acetylide. CujCg. Prepare an ammoniacal solution of cuprous chloride by first adding dilute ammonia to 2-3 ml. of dilute copper sulphate solution until the initial precipitate just redissolves and a clear deep-blue solution is obtained now add an aqueous solution of hydroxylamine hydrochloride drop by drop with shaking until the solution becomes first green and then completely colourless, the cupric salt being thus reduced to the cuprous derivative. [Pg.87]

Now add this solution to ajar of acetylene as before and shake vigorously. A chocolate-red precipitate of cuprous acetylide is at once formed. [Pg.87]

Now add this solution to a jar of acetylene and shake. A yellow-white precipitate of silver acetylide at once forms. [Pg.87]

The cuprous and silver acetylides are both explosive when dry. Therefore when these tests are completed, wash out the gas-jars thoroughly with water. [Pg.87]

The only reaction which calls for comment here is the formation of red cuprous acetylide with an ammoniacal solution of cuprous chloride ... [Pg.245]

A solution of mono-sodium acetylide in liquid ammonia is formed by passing excess of acetylene gas into the suspension of sodamide ... [Pg.896]

The reaction between sodium acetylide in liquid ammonia solution and carbonyl compounds gives a-acetylenyl carbinols (compare Section 111,148), for example ... [Pg.896]

Monosodium acetylide may also be prepared by the reaction of acetylene with sodium In liquid ammonia ... [Pg.896]

Some unreaeted sodium may be left 011 the walls of the flask in this method and this may partly reduee soino produet, siieh as an alkylaeetylene, derived from the sodium acetylide. The preparation of sodamide is not attended by mueh splashing and little (if any) unreaeted sodium remains on the walls of the flask. Although more manipulation and a somewhat longer time is required for the sodamide method, the latter is generally preferred as it is more adaptable and somewhat less troublesome. [Pg.896]

Ccasionally the reaction mixture does not become completely black nor free from suspended solid here the acetylide is in an insoluble (or sparingly soluble) form, but it gives satisfactory results in the preparation of hex-l-yne. The saturated solution of the soluble form of mono-sodium acetylide in liquid ammonia at — 34° is about i- M. [Pg.900]

The proton of terminal acetylenes is acidic (pKa= 25), thus they can be deprotonated to give acetylide anions which can undergo substitution reactions with alkyl halides, carbonyls, epoxides, etc. to give other acetylenes. [Pg.115]

Addition ofGrignard reagents to 1,1-difluoroethylene yields an acetylide anion which can be subsequently trapped with electrophiles. [Pg.117]

Synthesis The vinyl anion synthon can either be the vinyl Grignard reagent or the acetylide arrion, in which case the synthesis becomes ... [Pg.70]

The vinyl anion synthon is best represented by an acetylide ion (frame 33). Synthesis ... [Pg.106]

The stability of most acetylides, M-Ce8R, in organic solvents, even at room temperature or in liquid ammonia, allows a great variety of synthetic operations to be performed under different conditions (see inter alia refs. 1-5). Lithium... [Pg.8]

The stability of the various cumulenic anions depends to a large extent upon the nature of the groups linked to the cumulenic system. Whereas solutions of lithiated allenic ethers and sulfides in diethyl ether or THF can be kept for a limited period at about O C, the lithiated hydrocarbons LiCH=C=CH-R are transformed into the isomeric lithium acetylides at temperatures above about -20 C, probably via HC C-C(Li )R R Lithiated 1,2,4-trienes, LiCH=C=C-C=C-, are... [Pg.9]

A mixture of 0.40 mol of propargyl chloride and 150ml of dry diethyl ether was cooled at -90°C (liquid nitrogen bath) and a solution of 0.40 mol of ethyl-lithium (note 1) in about 350 ml of diethyl ether (see Exp. 1) was added with vigorous stirring and occasional cooling (note 2). The temperature of the reaction mixture was kept between -70 and -90°C. The formation of the lithium derivative proceeded almost instantaneously, so that the solution obtained could be used directly after the addition of the ethyl 1ithium, which was carried out in 15-20 min. This lithium acetylide solution is very unstable and must be kept below -60°C. [Pg.24]

Cumulenic anions, C=C=C and C=C=C=C, without strongly electron-withdrawing substituents are much stronger bases than acetylides, "CsC- and are therefore also stronger nucleophiles. In view of the poor stability of the cumulenic anions at normal temperatures this is a fortunate circumstance the usual functionalization reactions such as alkylation, trimethylsilylation and carboxylation in most cases proceed at a sufficient rate at low temperatures, provided that the... [Pg.27]

Note 2. In the absence of LiBr the coupling was much slower and yields of the carbinols were poor and moderate, respectively. With ketones such as acetone and soluble acetylides the yields were also excellent when no salt was added. [Pg.76]

Epichlorohydrin (1 mol) was added dropwise over a period of 1.5 h to a solution of 2.2 mol of sodium acetylide in 1.5 1 of liquid ammonia. During, as well as for a period of 1.5 h after, the addition the temperature of the mixture was kept at about -45°C. The cooling bath was removed after this period and the mixture was agitated vigorously for another 3 h. The thermometer and vent were removed, and 75 g of powdered ammonium chloride v/ere added in 2-g portions with vigorous stirring. The atimonia was allowed to evaporate. [Pg.78]

The last isomerization is remarkable in that the triple bond can shift through a long carbon chain to the terminus, where it is fixed as the (kinetically) stable acetylide. The reagent is a solution of potassium diami no-propyl amide in 1,3-di-aminopropane. In some cases alkali metal amides in liquid ammonia car also bring about "contra-thermodynamic" isomerizations the reactions are successful only if the triple bond is in the 2-position. [Pg.88]

The enyne system in the amines 828=88-8 8-882 can be reversed by potassium amide in liquid ammonia. Addition of the enyne amines to an equivalent amount of this reagent gives the potassium acetylides, K-8e8-88=88-8R2, from which the ynene" amines can be obtained in excellent yields by addition of solid ammonium chloride. [Pg.88]

Hove 1. The procedure described in Ref. 1 was modified. To a solution of 2.0 mol of lithium acetylide in 1.2 1 of liquid ammonia in a 4-1 round-bottomed, three-necked flask (see Fig. 2) was added 1.5 mol of freshly distilled benzaldehyde with cooling at about -45°C. After an additional 30 min finely powdered ammonium chloride (2 mol) was introduced in 15 min. The ammonia was allowed to evaporate, then water (1.1 1) was added and the product was extracted with diethyl ether. After drying over magnesium sulfate the extract was concentrated in a water-pump vacuum. High-vacuum distillation,... [Pg.178]

Alkynyl anions are more stable = 22) than the more saturated alkyl or alkenyl anions (p/Tj = 40-45). They may be obtained directly from terminal acetylenes by treatment with strong base, e.g. sodium amide (pA, of NH 35). Frequently magnesium acetylides are made in proton-metal exchange reactions with more reactive Grignard reagents. Copper and mercury acetylides are formed directly from the corresponding metal acetates and acetylenes under neutral conditions (G.E. Coates, 1977 R.P. Houghton, 1979). [Pg.5]

The only common synthons for alkynes are acetylide anions, which react as good nucleophiles with alkyl bromides (D.E. Ames, 1968) or carbonyl compounds (p. 52, 62f.). [Pg.36]

The addition of acetylides to oxiranes yields 3-alkyn-l-ols (F. Sondheimer, 1950 M.A. Adams, 1979 R.M. Carlson, 1974, 1975 K. Mori, 1976). The acetylene dianion and two a -synthons can also be used. 1,4-Diols with a carbon triple bond in between are formed from two carbonyl compounds (V. Jager, 1977, see p. 52). The triple bond can be either converted to a CIS- or frans-configurated double bond (M.A. Adams, 1979) or be hydrated to give a ketone (see pp. 52, 57, 131). [Pg.64]

Terminal alkynes are only reduced in the presence of proton donors, e.g. ammonium sulfate, because the acetylide anion does not take up further electrons. If, however, an internal C—C triple bond is to be hydrogenated without any reduction of terminal, it is advisable to add sodium amide to the alkyne solution Hrst. On catalytic hydrogenation the less hindered triple bonds are reduced first (N.A. Dobson, 1955, 1961). [Pg.100]


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Acetylene acetylide anion formation from

Acetylene and its salts (acetylides)

Acetylide

Acetylide

Acetylide (Ethynylsodium)

Acetylide Alkylation and Addition

Acetylide Complexes of Silver Salts

Acetylide Ligands

Acetylide addition

Acetylide alkylation

Acetylide anion

Acetylide anion alkylation

Acetylide anion alkynyl

Acetylide anion electrostatic potential map

Acetylide anion formation

Acetylide anion stability

Acetylide anions reactions with alkyl halides

Acetylide anions reactions with epoxides

Acetylide attack

Acetylide cluster

Acetylide complexes

Acetylide complexes cluster chemistry

Acetylide complexes, applications

Acetylide dianion

Acetylide dianions

Acetylide formation, Castro-Stephens reaction

Acetylide ion

Acetylide ions acylation

Acetylide ions alkylation

Acetylide ions carbonyl compound reactions

Acetylide ions formation

Acetylide ions halogenation

Acetylide ions ketones

Acetylide ions reaction

Acetylide ions synthesis using

Acetylide ions with aldehydes

Acetylide ions, -shifts

Acetylide ligands, geometry

Acetylide nucleophiles

Acetylide osmium complexes

Acetylide, structure

Acetylide-metal complexes, third-order

Acetylide/vinylidene pairs

Acetylides alkali metal

Acetylides aluminium

Acetylides and Fulminates

Acetylides bridging

Acetylides calcium acetylide

Acetylides coupling reactions, 1-haloalkynes

Acetylides cupric acetylide

Acetylides cuprous acetylide

Acetylides decomposition

Acetylides double bonds from

Acetylides formation

Acetylides from acetylenes

Acetylides group

Acetylides labelled acetylenes

Acetylides ligands

Acetylides mercury acetylide

Acetylides organometallic

Acetylides oxidative coupling

Acetylides oxidative coupling reactions

Acetylides reactions with

Acetylides reactions with carbonyl compounds

Acetylides silver acetylide

Acetylides synthesis

Acetylides, cross-coupling with terminal

Acetylides, cross-coupling with terminal alkynes

Acetylides, donor-acceptor complexes

Acetylides, hazards

Action of Carbon Dioxide on Sodium Acetylides in Dry Ether

Acylation Lithium acetylides

Agents sodium acetylide

Alcohols with acetylides

Aldehydes acetylides

Aldehydes reaction with acetylides

Alkenes copper acetylides

Alkyl halides reaction with acetylides

Alkyl halides with acetylide anions

Alkyl sulfates with acetylides

Alkyl sulfonates with acetylides

Alkyl with acetylide anions

Alkylation of Acetylide Anions

Alkyne Acidity Formation of Acetylide Anions

Alkyne acetylide anions from

Alkyne anions acetylides

Alkynes acetylides from

Alkynes acetylides, derived

Alkynes from acetylides, mechanism

Alkynes synthesis in acetylide anion

Alkynes transition metal acetylides

Alkynes using acetylide ions

Alkynyl ligand exchange, metal-acetylide

Alkynylation, copper acetylides

Aluminum Acetylide

Ammonium acetylid

Ammonium acetylide

Analytical Procedures for Acetylides

Aryl acetylides

Arylation copper acetylides

Aurous acetylide

Barium Acetylide

Beryllium Acetylide

Beryllium Acetylide Azide

Beryllium Carbide. .See under Acetylides

Beryllium Carbide. .See under Acetylides and Carbides

Beryllium acetylide crystal structure

Beryllium acetylide structure

Bipyridyl acetylides

Boranes with acetylides

COMPLEX ACETYLIDES

Cadmium Acetylide

Calcium Acetylide

Calcium Hydrogen Acetylide

Carbanions acetylide

Carbanions acetylide anion

Carbon as a nucleophile nitriles, Grignard reagents, acetylides

Carbon nucleophiles metal acetylide

Carbonyl compounds with acetylide ions

Castro-Stephens reaction copper acetylide preparation

Cerium acetylides

Cesium Acetylide-Acetylene

Cesium Hydrogen Acetylide

Cesium acetylide

Chiral metal-acetylide

Chlorates Copper Acetylides

Cobaltous Acetylide

Copper Acetylides, Analytical Procedures

Copper I) acetylides

Copper acetylide

Copper acetylide Cadiot-Chodkiewicz reaction

Copper acetylide Castro-Stephens reaction

Copper acetylide catalysis

Copper acetylide complexes

Copper acetylide/alkynyl

Copper acetylides

Copper acetylides, cross-coupling with

Copper acetylides, cross-coupling with halides

Copper® acetylides Cadiot-Chodkiewicz coupling

Copper® acetylides synthesis

Cr-acetylide complex

Cu-acetylide

Cupric acetylide

Cuprous Acetylide-Chloride

Cuprous Hydrogen Acetylide

Cuprous acetylide

Cycloheptatrienyl-acetylide

Cyclohexanone with sodium acetylide

Dilithium acetylide

Dimeric copper acetylide

Dimeric copper acetylide complexes

Disodium acetylide

Electron-rich acetylides

Electrophilic reactions lithium acetylides

Enantioselective acetylide addition

Epoxides with acetylide anions

Epoxides with acetylides

Explosives copper acetylide

Explosives silver acetylide

Ferrous Acetylide

Formation of a Silver Acetylide and Its Decomposition

Gold Acetylide

Gold acetylides

Gold acetylides luminescent

Gold acetylides synthesis

Gold complexes acetylide

Group 8 Metal Acetylide Complexes

Halides, aryl reaction with copper acetylides

Heavy metal acetylides

Hydrolysis with acetylides

I) (2-iodophenyl)acetylide

INDEX Acetylide

Intramolecular acetylide-aldehyde addition

Iron Acetylide

Isoxazoles acetylides

Ketones reaction with acetylides

Lead Acetylide

Lithioum/magnesium acetylide Subject

Lithioum/magnesium acetylide crystal structure

Lithium acetylide

Lithium acetylide ethylenediamine complex

Lithium acetylide reaction with epoxides

Lithium acetylide reagent

Lithium acetylide, addition

Lithium acetylide-Ethylenediamine

Lithium acetylide-ethylene diamine complex

Lithium acetylides

Lithium acetylides ethylenediamine complex

Lithium acetylides, oxygenation

Lithium compounds, organolithium acetylide

Lithium/magnesium acetylide

METAL ACETYLIDES

Magnesium Acetylide

Magnesium acetylides

Magnesium acetylides, structure

Manganese Acetylide

Manganese complexes acetylides

Mechanism acetylide alkylation

Mercuric acetylide

Mercurous acetylide

Mercury Acetylides

Mercury acetylide

Metal acetylide coupling

Metal acetylides calcium acetylide

Metal acetylides copper acetylide

Metal acetylides cupric acetylide

Metal acetylides cuprous acetylide

Metal acetylides mercury acetylide

Metal acetylides silver acetylide

Metal acetylides, structure

Metal-acetylide complexes

Metal-acetylide polymers

Migration acetylide groups

Molybdenum acetylide complexes

Monorubidium acetylide

Monosodium acetylide

New Reactions of Copper Acetylides Catalytic Dipolar Cycloadditions and Beyond

Nickel acetylide

Nucleophiles acetylide anions

Nucleophiles acetylides

Nucleophilic addition acetylide ions

Nucleophilic addition of acetylide

Nucleophilic metal acetylides

Optical acetylide metal complex

Organometallic acetylide polymers

Organometallic reagents acetylide anions

Organometallics Grignard reagents and acetylides

Organotin acetylides

Other Mixed Metal Acetylide Complexes

Oxidative Acetylide Coupling

Oxidative coupling organometallic acetylides

Phenyl copper acetylide

Phosphine metal acetylide derivatives

Platinum Acetylide Containing Conjugated Polymers

Platinum acetylide complexes

Platinum acetylide dendrons

Platinum acetylide polymers

Platinum acetylides

Platinum complexes acetylides

Polyynes metal acetylide

Potassium Hydrogen Acetylide

Potassium acetylide

Preparation of Acetylide Complexes

Pt bis-acetylide

Pure metal acetylides and alkynyls

Pyridine 1-oxide reaction with sodium acetylide

Reaction Mechanism for the Lithium Acetylide Addition to pMB Protected Amino Ketone

Reaction Mechanism for the Zinc Acetylide Addition to Amino Ketone

Reaction of Acetylide Anions

Reaction with acetylide ions

Reaction with lithium acetylides

Reactions of Copper Acetylides with Other Dipoles

Reagents metal acetylide

Rearrangement acetylide ions

Rigid-rod transition metal-acetylide polymers

Ring acetylide-aldehyde

Rubidium Acetylide

Rubidium Hydrogen Acetylide

Ruthenium Acetylide, Vinylidene, and Carbene Complexes

Ruthenium complex acetylide

SUBSTITUTION OF ARYL HALIDES WITH COPPER ACETYLIDES

Safety acetylides

Secondary alkyl halides acetylide anion reactions with

Silver Acetylide, Analytical

Silver Acetylide, Analytical and Destruction

Silver Acetylide, Destruction

Silver acetylide

Silver acetylide nitrate

Silver acetylide, decomposition

Silver acetylide-hexanitrate

Silver acetylides

Silver acetylides dioxide

Silver acetylides reactivity

Silver acetylides synthesis

Silver’Acetylide Complexes

Sodium Hydrogen Acetylide

Sodium acetylide

Sodium acetylide alkyl halides

Sodium acetylide compounds

Sodium acetylide cyclohexanone

Sodium acetylide formation

Sodium acetylide generation

Sodium acetylide preparation

Sodium acetylide reaction with

Sodium acetylide reaction with, alkyl halides

Sodium acetylide reactions

Sodium acetylide reduction

Sodium acetylide, from deprotonation

Sodium acetylide, solution in liquid

Sodium acetylide, solution in liquid ammonia

Sodium, acetylide benzyl

Sodium, acetylide hydrocarbons

Sodium, acetylide phenyl

Sonogashira coupling metal acetylides

Stephens-Castro coupling copper acetylide intermediates

Stereoselectivity acetylides

Stereospecificity acetylides

Strontium acetylide

Synthesis of Alkynes from Acetylides

Terminal alkyne acetylide

The Generation of Sodium Acetylide in Tetrahydrofuran

The Generation of Sodium Acetylide via Dimsylsodium

Tin acetylide

Tin acetylides

Titanium acetylides

Transition metal acetylides

Transition metal acetylides and alkynyls

Using acetylenic reactivity nucleophilic substitution with metal acetylides and related reactions

Vanadium acetylides

Vinylidene complexes from metal acetylides

Zinc Acetylide

Zinc acetylides

Zirconium acetylides

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