---------------------------------------------------------------------- V. F. Brameld, M. T. Clark, A. P. Seyfang (1947): "Copper acetylides". ''Journal of the Society of Chemical Industry'', volume 66, issue 10, pages 346-353. {{doi|10.1002/jctb.5000661007}} Following an introduction and a brief review of published work on copper acetylides, investigations into conditions of formation and properties of copper acetylides are described. Parts I and II deal with formation from acid and alkaline, cuprous and cupric solutions. Part III concerns the formation of acetylides on the surfaces of copper and copper alloys under varying conditions. Although acetylides cannot be formed in cupric solutions above a certain acid concentration, they can be formed on the surfaces of copper and brasses immersed in such solutions even if the acidity is greatly increased. Explosive acetylides can be formed not only on copper and high-copper alloys in ammoniacal acetylene atmospheres, but also on copper and brasses containing 50% copper or more, when these have been contaminated with acids or caustic alkalis. Methods are given for the detection of small amounts of copper acetylide. [MUST GET] ---------------------------------------------------------------------- Ata Makarem, Dr. Regina Berg, Dr. Frank Rominger, Prof. Dr. Bernd F. Straub (2015): "A fluxional copper acetylide cluster in CuAAC catalysis". ''Angewandte Chemie International Edition'', volume 54, issue 25, pages 7431-7435. {{doi|10.1002/anie.201502368}} A catalytically active octacopper(I) hexaacetylide salt was formed from a dinuclear copper complex and ethyl propiolate, thereby providing new insights into the influence of the coordination mode of the acetylide ligand on the stability and catalytic activity. [Not interesting] ---------------------------------------------------------------------- Maria A. Garcia, Michael D. Morse (2013): "Electronic spectroscopy and electronic structure of copper acetylide, CuCCH". ''Journal of Physical Chemistry A'', volume 117, issue 39, pages 9860–9870. {{doi|10.1021/jp312841q}} The optical spectrum of the linear CuCCH molecule has been investigated for the first time, using resonant two-photon ionization spectroscopy employing ArF (193 nm) or F2 (157 nm) excimer radiation for photoionization. Scans over the range 19 400–25 200 cm–1 were conducted, leading to the observation of three electronic band systems. These are identified as the [20.2] ã1 ← X̃ 1Σ+, the [23.1] à 1Σ+ ← X̃ 1Σ+, and the [24.7] B̃ 1Π ← X̃ 1Σ+ systems, although only the first two have been rotationally resolved. The ã1 state is tentatively assigned as having 3Π1 symmetry, becoming optically accessible through spin–orbit interaction with the B̃ 1Π state. Vibrational assignments have provided the frequency of the Cu—C stretching mode, ν3, in the ground and all three excited states, along with both bending modes, ν4 and ν5, in the à 1Σ+ and B̃ 1Π states, and the Cu—C≡C bending mode, ν5, in the ground state. Comparisons are made to the known electronic states of CuF, CuCl, CuBr, and CuI, and it is argued that like these molecules, the CuCCH molecule is essentially ionic in both the ground and excited states, with the ground state correlating diabatically to Cu+ (3d10, 1S) + CCH– (X̃ 1Σ+) and the excited states correlating diabatically to Cu+ (3d94s1, 1,3D) + CCH– (X̃ 1Σ+). [MUST GET] ---------------------------------------------------------------------- A. M. Sladkov, Lev Yu. Ukhin (1968): "Copper and silver acetylides in organic synthesis". ''Russian Chemical Reviews'', volume 37, issue 10, pages 748-762. {{doi|10.1070/RC1968v037n10ABEH001701}} A review of the reactions of copper, silver, and gold acetylides with halides, aryl halides, unsaturated halogen compounds, diazonium salts, halides of organic acids, and organometallic compounds. Information on the structure of copper and silver acetylides and their physical properties is given. The mechanisms of the reactions of copper acetylides with the above types of compounds and the mechanism of the oxidative condensation of acetylenes are considered. The properties of copper and silver acetylides are compared with the properties of the cyanides of these metals. Bibliography of 127 references. [MUST GET] ---------------------------------------------------------------------- Yu Yamane, Naoki Miwa, Takashi Nishikata (2017): "Copper-catalyzed functionalized tertiary-alkylative Sonogashira type couplings via copper acetylide at room temperature". ''ACS Catalysis'', volume 7, issue 10, pages 6872–6876. {{doi|10.1021/acscatal.7b02615}} There are several reports on Sonogashira couplings, but most of the reported reactions have employed aryl or alkenyl halides as coupling partners. Therefore, Sonogashira coupling is unsuitable for alkyl loadings, especially tertiary alkyl groups. In this research, we found that a copper catalyst is effective for a reaction between a terminal alkyne and an α-bromocarbonyl compound to form a quaternary carbon having alkynyl group at room temperature. Control experiments revealed that a copper acetylide is a key intermediate. [No need to get full article] ---------------------------------------------------------------------- A. Francis Adeleke , Alexander P. N. Brown , Li-Jie Cheng , Kari A. M. Mosleh , Christopher J. Cordier (2017): "Recent advances in catalytic transformations involving copper acetylides". ''Synthesis'', volume 49, issue 04, pages 790-801. {{doi|10.1055/s-0036-1588405}} This review will discuss recent advances in catalytic transformations involving copper acetylides. The content is organized according to the site of functionalization: cross-couplings and direct nucleo­philicity (C1-functionalization), formal cycloadditions (C2-functionalization), and propargylic substitutions (C3-functionalization). [Not essential] ---------------------------------------------------------------------- L. K. Ding and W. J. Irwin (1976): "''Cis''- and ''trans''-azetidin-2-ones from nitrones and copper acetylide". ''Journal of the Chemical Society, Perkin Transactions 1'', volume 1976, issue 22, pages 2382-2386. {{doi|10.1039/P19760002382}} The reaction between nitrones and copper acetylides in pyridine yields cis- and trans-azetidinones. Deuteriation and isomerisation studies indicate that the trans-compound is produced from the initially formed cis-isomer and that the amount of cis-product may be increased by using non-basic solvents. Lactams with aromatic, aliphatic, and ethoxycarbonyl substituents may be obtained from appropriately substituted acetylenes, and the use of cyclic nitrones leads to bicyclic compounds. [Does not seem to be essentia] ---------------------------------------------------------------------- Tobias Bruhm, Andrea Abram, Johannes Häusler, Oliver Thomys, Klaus Köhler(2021): "Walter Reppe Revival – Identification and genesis of copper acetylides Cu2C2 as active species in ethynylation reactions". ''Chemistry – A European Journal'', volume 27, issue 68, pages 16834-16839. {{doi|10.1002/chem.202101932}} More than six decades after proposing copper acetylide, Cu2C2, as catalytically active species in ethynylation reactions by Walter Reppe, the explosive species have been experimentally identified and investigated during catalysis in detail now. Taking into account specific safety precautions, unequivocal qualitative characterization was achieved by Raman spectroscopy and X-ray powder diffraction of supported copper catalysts Cu/Bi/SiO2 during and after activation and catalysis in comparison to bulk Cu2C2 materials. Quantification of Cu2C2 succeeded by thermal analysis and Raman spectroscopy. Its formation in aqueous suspension is studied starting from copper(II) oxide catalysts including dissolution, reduction and precipitation steps. Copper acetylide formation can be correlated with catalytic performance in the ethynylation of formaldehyde to 1,4-butynediol. [GOT IT] 2021-bruhm-copper-acetylides-Cu2C2-as-catalists.pdf * Stable only wet and in dilute solutions. * Crystalline Cu2C2 analyzed by X-ray powder diffraction. * General structure of solid Cu2C2 is a polymer where each Cu is attached to one end of a C2 and to the middle of another C2. * Hydrogen or substituted acetylide seems to be linear. True Cu2C2 is multibranched. ---------------------------------------------------------------------- G. Evano, K. Jouvin, C. Theunissen, C. Guissart, A. Laouiti, C. Tresse, J. Heimburger, Y. Bouhoute, R. Veillard, M. Lecomte, A. Nitelet, S. Schweizer, N. Blanchard, C. Alayrac and A.-C. Gaumont (2014): "Turning unreactive copper acetylides into remarkably powerful and mild alkyne transfer reagents by oxidative umpolung". ''Chemical Communications'', volume 50, issue 70, pages 10008-10018. {{doi|10.1039/C4CC03198A}} Copper acetylides R-CC-Cu, readily available polymeric rock-stable solids, have been known for more than a century to be unreactive species and piteous nucleophiles. This lack of reactivity actually makes them ideal alkyne transfer reagents that can be easily activated under mild oxidizing conditions. When treated with molecular oxygen in the presence of simple chelating nitrogen ligands such as TMEDA, phenanthroline or imidazole derivatives, they are smoothly oxidized to highly electrophilic species that formally behave like acetylenic carbocations and can therefore be used for the mild and practical alkynylation of a wide range of nitrogen, phosphorus and carbon nucleophiles. [Not essential] [GOT IT] 2014-evano-activating-copper-acetylides-by-oxidation.pdf ---------------------------------------------------------------------- Ken Judai, Shigenori Numao, Junichi Nishijo, Nobuyuki Nishi (2011): "In situ preparation and catalytic activation of copper nanoparticles from acetylide molecules". ''Journal of Molecular Catalysis A: Chemical'', volume 347, issue 1–2, pages 28-33. {{doi|10.1016/j.molcata.2011.07.006}} Because metal nanoparticles have a high surface area to volume ratio, they can be highly reactive, cost-effective catalysts. However, metallic surfaces are usually too reactive to maintain their metallic character in the presence of oxygen and/or water vapor. Metal nanoparticle catalysts must be handled carefully to avoid oxidation and inactivation. Here, we suggest a facile in situ preparation method for metal nanoparticle catalysts. Copper acetylide and copper methyl-acetylide molecules are based on ionic bonding, and are relatively stable in air. They can be used as a precursor of copper nanoparticles. Due to their instability at increased temperatures, subsequent annealing promotes a segregation reaction into elemental copper and carbon. Transmission electron microscopy and powder X-ray diffraction revealed that the average diameters of the Cu nanoparticles thus formed were 13.3 and 4.4 nm for C2Cu2 and CuCC–CH3 precursors, respectively. This suggests that the substitution of acetylide molecules can control the size of the resulting copper nanoparticles. The primary advantage of this preparation method is that the functional acetylide group can reduce copper cations. No additional reducing agent is required, so no further separation process is necessary. This presents in situ preparation process. The catalytic activity of the resulting Cu nanoparticles was confirmed for a hydrogen storage system. [GOT IT] 2011-judai-copper-nanoparticles-from-acetylide.pdf * Cu2C2 and H3C-C2-Cu. * Annealing at 200 C. * Result is copper particles encased in semipermeable amorphous carbon. * Particle diameters 13.1 nm for Cu2C2 and 4.4 nm for H3C-C2-Cu. ---------------------------------------------------------------------- Franco Cataldo, Carlo S. Casari (2007): "Synthesis, structure and thermal properties of copper and silver polyynides and acetylides". ''Journal of Inorganic and Organometallic Polymers and Materials'', volume 17, pages 641–651. {{doi|10.1007/s10904-007-9150-3}}{{pmid|96278932}} Polyynes or oligoynes having general formula H–(C≡C)n–H with n = 1,2,3,4,..., are a class of molecules that has become easily accessible in recent years due to new synthetic approaches. These molecules form copper and silver salts, which have been called, respectively, Cu-polyynides and Ag-polyynides. Here we show the synthesis of these salts and discuss their FT-IR spectra and thermal behaviour, which is studied by Differential Scanning Calorimetry (DSC). These properties are compared to the spectra and thermal behaviour of Cu2C2 and Ag2C2. It is shown that Cu2C2 can be oxidized to Cu-polyynides thereby loosing its original structure and becoming a polymeric coordinative structure. The structural changes make Cu-polyynides no more explosive than the parent Cu2C2. Similarly, Ag-polyynides, which decompose exothermally when heated, are not explosive compared to Ag2C2. The explosive decomposition of Cu2C2 occurs at 127 °C (DSC) whereas Ag2C2 decomposes explosively at 169 °C under the same conditions. Conversely, Cu-polyynides, when heated in the DSC, show a broad exothermal peak at about 243 °C. Ag-polyynides decompose near 94 °C and the release of energy is sufficiently gradual that no explosion is detected. [GOT IT] 2007-cataldo-synth-struct-props-copper-stlver-polyynides-acetylides.pdf * Pure Cu2C2 is formed from H2C2 and CuCl when the solution is reducing, e.g. because or H2NOH or H2N-NH2. * Pure Ag2C2 is formed even without the reducing agents. * Oxidation by ageing in air, H2O2, or Cu++ creates polyyinides Cu-(C≡C)n-Cu or Ag-(C≡C)n-Ag. * These polyyinides are decomposed by HCl generating H-(C≡C)n-H that are soluble in hexanes. * The polyynides can be reformed by stirring the hexane soln of H-(C≡C)n-H with AgNO3 in aq ammonia. * Cu2C2 does not show IR absorption from C≡C stretching but that is normal. * Cu-(C≡C)n-Cu shows that band increasingly as n increases. * There are signs of cumulene resonance. * There is stillno X-ray structure for Cu2C2, but there is some for Ph-C≡C-Cu * The copper atoms are bound to the end of the polyyine chain but also sideways to C≡C of adjacent chains. ---------------------------------------------------------------------- Mårten Ahlquist, Valery V. Fokin (2007): "Enhanced reactivity of dinuclear copper(I) acetylides in dipolar cycloadditions". ''Organometallics'', volume 26, issue 18, pages 4389–4391. {{doi|10.1021/om700669v}} Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate itself. These findings support the experimentally determined rate law and shed light on the origin of high reactivity of the insitu generated copper acetylides. [Not so important] * A "dinuclear complex" has two copper atonms, one terminal on the C2, the other binding to the side of the C2. ---------------------------------------------------------------------- Ulrich Cremer, Winfried Kockelmann, Marko Bertmer, Uwe Ruschewitz (2002): "Alkali metal copper acetylides ACuC2 (A=Na–Cs): Synthesis, crystal structures and spectroscopic properties". ''Solid State Sciences'', volume 4, issue 2, pages 247-253. {{doi|10.1016/S1293-2558(01)01234-1}} By reaction of CuI and A2C2 (A = K, Rb, Cs) suspended in liquid ammonia and subsequent heating of the remaining residue in vacuum ternary alkali metal copper acetylides ACuC2 were accessible. NaCuC2 could be obtained by decomposing NaCu5C6, which was synthesized from NaC2H and CuI in liquid ammonia. The crystal structures were determined by both X-ray and neutron powder diffraction. In all compounds, [CuC≡C(2-)]n chains are the characteristic structural motif. In NaCuC2 and β-RbCuC2 these chains are orientated parallel to the c axis of a tetragonal unit cell (KAgC2 type, P4/mmm, Z=1), whereas in KCuC2, α-RbCuC2 and CsCuC2 these chains are arranged in layers perpendicular to the c axis of a tetragonal unit cell (CsAgC2 type, P42/mmc, Z=2). These layers are staggered along the c axis by rotating them by 90° to each other. The alkali metal ions separate the copper carbon chains. Raman spectroscopic investigations indicate the existence of C≡C ≡s, as the frequencies of the C≡C stretching vibration are comparable to those found for acetylene and ternary silver and gold acetylides. In the 13C MAS NMR spectra of KCuC2, RbCuC2 and CsCuC2 the isotropic signals are complicatedly split due to the coupling to the nearby quadrupolar copper nuclei, but the chemical shifts are in the range found for other acetylides with C≡C ≡s. [GOT IT] 2002-cremer-mixed-copper-Na-K-Rb-Cs-acetylides-synth-struct.pdf ---------------------------------------------------------------------- John S. Kiely, Philip Boudjouk, Lawrence L. Nelson (1977): "A synthesis of terminal arylacetylenes - An in situ generated copper(I) acetylide". ''Journal of Organic Chemistry'', volume 42, issue 15, pages 2626–2629. {{doi|10.1021/jo00435a020}} [GOT IT] 1977-kiely-synth-monocopper-phenylacetylide.pdf *Generates copper(1) 3,3-diethoxy-1-propynide by dissolving 1,1-diethoxy-2-propyne in dry tetrahydrofuran, deprotonates with n-butyllithim, then adds CuI that dissolves forming the desired product, which is soluble. ---------------------------------------------------------------------- Charles E. Castro, R. Havlin, V. K. Honwad, A. M. Malte, Steve W. Moje (1969): "Copper(I) substitutions. Scope and mechanism of cuprous acetylide substitutions". ''Journal of the American Chemical Society'', volume 91, issue 23, pages 6464–6470. {{doi|10.1021/ja01051a049}} [Not very relevant] ---------------------------------------------------------------------- Franco Cataldo (1999): "From dicopper acetylide to carbyne". '''', volume 48, issue 1, pages 15-22. {{doi|10.1002/(SICI)1097-0126(199901)48:1<15::AID-PI85>3.0.CO;2-%23}} Freshly prepared dicopper acetylide, air-aged and Cu 2+ oxidized samples have been studied by FTIR and electronic spectroscopy. There is some evidence about the polymeric and semiconductive nature of dicopper acetylide, and it is proposed to represent this compound by the general formula (Cu2 C2 · nH2O)x in which n=0.5–1 and x is unknown but large. It has been found that upon oxidation, the acetylide ion C22+ in copper acetylide undergoes a coupling reaction with formation of a diacetylene derivative and/or its higher homologues. No definitive evidence about the presence of cumulenic isomers has been found. After hydrolysis of dicopper acetylide in HCl, acetylene (the main product) together with a mixture of polyynes having the general formula H-(C≡C)n-H with n=1, 2, 3, 4, 5, 6 has been identified by electronic spectroscopy. The carbonaceous insoluble matter, obtained from aged/oxidized dicopper acetylide, hydrolyzed in HCl is carbyne as indicated by the FTIR band at 2200 cm−1. It has been shown that carbyne is also formed by oxidizing dicopper acetylide with H2O2 in aqueous ammonia suspension (FTIR bands at 2203 and 2139 cm−1), and is recovered as insoluble carbonaceous matter. Carbyne is also formed by thermal decomposition of dicopper acetylide in vacuo. Under these conditions, carbyne is a fluffy, very fine carbon powder having a high tint strength, whose FTIR spectrum shows bands at 2220 and 2200 cm−1 due to ≡ stretching vibrations. Volatile compounds are sublimable from carbyne and have been studied by electronic spectroscopy. [GOT IT] 1999-cataldo-from-dicopper-acetylide-to-carbyne.pdf * Freshly prepared Cu2C2 is a hydrate with n between 0.5 and 1.0. * Decomp with HCl generates acetylene but also higher polyalkynes. * Aging/oxidation produces carbyne. * Thermal decomp in vacuum also produces carbyne as a very fine fluffy powder, with volatile components. * No sign of cumulenes (isomers of csrbynes). ---------------------------------------------------------------------- Robert Matyáš, Jiří Pachman (2012): "Acetylides". Chapter of ''Primary Explosives'', pages 303–324. {{doi|10.1007/978-3-642-28436-6_12}} {{isbn|978-3-642-28435-9}} Acetylides are salts of acetylene, which is, under normal conditions, a gas with a slightly acidic character (pK a is 25, for comparison pK a 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 (C2H2·MX) [GOT IT] * pKa of acetylene. * Addition compounds H2C2 + MX. ---------------------------------------------------------------------- Jimmie C. Oxley, James L. Smith, F. Lucus Steinkamp, Jayant Gorawara, Vlado Kanazirev (2017): "Study on exposing supported copper compounds to acetylene". ''Journal of Chemical Health & Safety'', volume 24, issue 2, pages 26–33. {{doi|10.1016/j.jchas.2016.06.001}} Copper acetylide is used to describe copper and acetylene containing compounds. Depending on the valence of copper involved in reaction with acetylene, cuprous acetylide is formed from cuprous ion (Cu+) while cupric acetylide is formed from cupric ion (Cu2+). This study addresses the use of copper materials for removal of mercury and the potential for accidental accumulation of copper acetylides in the process. Alumina supports with copper oxide, copper carbonate or copper sulfide were exposed to acetylene and a variety of analytical techniques used to evaluate their potential for accumulation of copper acetylides. Copper oxide and copper carbonate exposed to acetylene did not demonstrate accumulation of either cuprous or cupric acetylides. However, resulting accumulated materials were energetic as they decomposed with release of heat during Differential Scanning Calorimeter analysis. The exothermic event was not excessive and it was speculated that the reaction involved copper oxide and carbon at elevated temperature. There was no apparent reaction between copper sulfide and acetylene. The condition for exposure of acetylene to the copper materials in this study was extreme. It concludes that when the copper materials are used for mercury recovery there is no apparent accumulation of copper acetylides. [MODERATELY RELEVANT] * Cu2C2 forms when CuO or CuCO3 is exposed to acetylene. * They did not accumulate but decomposed with "not excessive" release of heat. ---------------------------------------------------------------------- S. Díez-González (2016): "Copper(I) acetylides: Access, structure, and relevance in catalysis". Chapter 3 of ''Advances in Organometallic Chemistry'', volume 66, pages 93-141. {{doi|10.1016/bs.adomc.2016.08.001}} Ethyne-1,2-diylcopper(I) [Cu2C2] was the first organocopper(I) compound ever reported.1 Prepared by bubbling acetylene through a solution of CuCl in aqueous ammonia, this energetic reagent is stable while wet, but explosive when dry. The explosive decomposition of [Cu2C2] can be initiated by either heating above 120°C, impact, or electric spark. On the other hand, alkynide copper(I) derivatives were only reported a century later, but they have become increasingly popular due to their straightforward synthesis, commercial availability, and remarkable thermal and shock stability. Actually, in spite of the Cu–C bond, some of these yellow-orange compounds are among the most stable copper(I) derivatives and might be stored for prolonged periods of time, which is directly linked to their polymeric structures. Homoleptic [CuC≡CR] complexes remain rare in the literature and only recently have the solid structures for R = t-Bu, n-Pr, and Ph been elucidated. tert-Butylethynylcopper(I) displayed a C20 cluster structure with an interlocking of a distorted Cu8 ring with two hexagonal C6 rings. Each of the rings was supported by μ,η1,1-C≡C–Cu2 and μ,η1,2-C≡C–Cu2 bonding, while μ3,η1,1,2-C≡C–Cu3 and μ4,η1,1,1,1,2-C≡C–Cu4 bridging modes were found to bring the Cu atoms of different rings together (Fig. 1). On the other hand, phenylethynylcopper(I) has a polymeric ladderane structure with short copper(I)–copper(I) distances, ranging from 2.49 to 2.83 Å and μ,η1,2-C≡C bridging ligands. Hence, both steric and electronic properties of the alkynyl ligands have a strong influence on the actual structures. The use of additional ligands does improve the solubility of the obtained complexes, but still lead to highly aggregated species with a range of σ- and π-interactions solid structures. [GOT IT] 2016-gonzalez-copper-I-acetylides-access-struct-catal.pdf * Decomposes when shocked or heated at 120 C. ---------------------------------------------------------------------- F. Cataldo (1998): "Structural relationships between dicopper diacetylide (Cu-C≡C-C≡C-Cu) and dicopper acetylide (Cu-C≡C-Cu)". ''European Journal of Solid State and Inorganic Chemistry'', volume 35, issue 3, pages 281-291. {{doi|10.1016/S0992-4361(98)80009-X}} Dicopper diacetylide Cu-C≡C-C≡C-Cu, prepared from butadiyne has been studied by FT-IR spectroscopy in comparison to dicopper acetylide Cu-C≡C-Cu. Upon ageing by exposure to air at room temperature, Cu-C≡C-Cu has been transformed into Cu-C≡C-C≡C-Cu as demonstrated by FT-IR spectroscopy and this compound is further transformed on standing in air. A special kind of solid state oxidative coupling reaction occurs so that polyynes chains are formed in these aged solids. It is shown that the FT-IR spectrum of copper acetylide prepared from ammonia solutions of Cu+ and Cu2+ ions is comparable to that of air oxidized Cu-C≡C-Cu (and Cu-C≡C-C≡C-Cu) prepared exclusively from Cu+ ions in presence of a reducing agent demonstrating that Cu2+ ions display the same oxidizing effect as oxygen causing coupling reactions in solution and producing Cu-C≡C-C≡C-Cu. Cu-C≡C-Cu oxidized at 60–70°C with CuCl2 produces a product which could be formulated as {{chem2|Cu(C≡C)20Cu}}; FT-IR absorption at 1950 cm−1 could suggest the presence of cumulenic carbon chain although acetylenic carbon chains cannot be excluded completely. [GOT IT] 1998-cataldo-dicopper-acetylide-diacetylide.pdf * Cu(2+) or O2 oxidizes C2C2 to Cu2C4 * Higher polyynides can be obtained by hot oxidation. * Cumulenes more likely than polyynes. ---------------------------------------------------------------------- D. A. Katskov, I. L. Grinshtein (1982): "Formation of copper, silver, and calcium acetylides in graphite furnaces for atomic absorpion analysis". ''Zhurnal Prikladnoi Spektroskopii'', volume 36, issue 2, pages 181-185. {{doi|}} [GOT IT] 1982-katskov-copper-calcium-silver-acetylides-from-graphite-in-furnace.pdf * Acetylides of Cu, Ag, Ca are formed asthin film on graphite by reaction of oxide of metal and graphite in argon atmosphere. * Nitrate of metal is decomposed at 700-800 K on an electrically heated porous graphite rod. Argon saturated with H2O vapor is blown over rod heated at 2000 to 2600 K. Acetilyde formed in situ is decomposed by the H2O and the acetylene is detected by bubbligh though indicator solution. * Acetylide is not formed at 1150 K, or with glassy pyrographite,or with Al, Cr which form other carbides. * Previous refs say that min tempereature is 1400 K to form Cu2C2, 1450 K to form Ag2C2 at 1450 K, and 2000 K to form CaC2. * Au, Sr, Ba form acetylides? * EuC2 and GdC2 are known. ---------------------------------------------------------------------- Y. N. Zhitnev, E. A. Tveritinova, V. V. Lunin (2008): "Catalytic properties of a copper-carbon system formed by explosive decomposition of copper acetylide". ''Russian Journal of Physical Chemistry A'', volume 82, issue 1, pages 140–143. {{doi|10.1134/S003602440801024X}} The catalytic properties of a copper-carbon system formed by the explosive decomposition of copper acetylide in the propanol-2 dehydrogenation and dehydration reaction were studied by the pulse microcatalytic method over the temperature range 60–350°C. The extent of conversion was as high as 85%. It was established that the ratio between the catalytic conversion channels of propanol-2 depended on the method of acetylide decomposition (explosion in air or in vacuum). [GOT IT] 2008-zhitnev-copper-carbon-catal-from-explosive-decomp-copper-acetylide.pdf * Catalytic activity continues after explosion? * Does not explode in vacuum? ---------------------------------------------------------------------- J. Bond (1987): "[https://www.icheme.org/media/25204/hazards-from-pressure-icheme-symposium-series-102-1987-5-bond.pdf Case studies on unstable substances]". ''Proc. IChemE Symposium on Hazards from Pressure: Exothermic Reactions, Unstable Substances, Pressure Relief and Accidental Discharge'', volume 102, pages 37-44. Expolsion with green flame happened on a copper heat exchanger used with some methanol product, containing intermittently 300 ppm of acetylene. Exchanger had been steamed out and exposed to atmosphere for three days. Black residue left on exchanger after explosion contained 9% Cu2C2, plus Cu2O, Cu, C. Sparkled when dropped on a hot plate. [GOT IT] 1987-bond-hazards-from-pressure.pdf * Claims that Cu2C2 forms when acetylene is exposed to metals with more than 50% copper. * Claims (with no direct evidence) that the explosion was due to the acetylide. * No information on HOW MUCH acetylide may have been present, or how much residue was left. ---------------------------------------------------------------------- Wan-Ho Chung, Yeon-Taek Hwang, Seung-Hyun Lee, Hak-Sung Kim (2016): "Electrical wire explosion process of copper/silver hybrid nano-particle ink and its sintering via flash white light to achieve high electrical conductivity". ''Nanotechnology'', volume 27, article 205704. {{doi|10.1088/0957-4484/27/20/205704}} In this work, combined silver/copper nanoparticles were fabricated by the electrical explosion of a metal wire. In this method, a high electrical current passes through the metal wire with a high voltage. Consequently, the metal wire evaporates and metal nanoparticles are formed. The diameters of the silver and copper nanoparticles were controlled by changing the voltage conditions. The fabricated silver and copper nano-inks were printed on a flexible polyimide (PI) substrate and sintered at room temperature via a flash light process, using a xenon lamp and varying the light energy. The microstructures of the sintered silver and copper films were observed using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). To investigate the crystal phases of the flash-light-sintered silver and copper films, x-ray diffraction (XRD) was performed. The absorption wavelengths of the silver and copper nanoinks were measured using ultraviolet–visible spectroscopy (UV–vis). Furthermore, the resistivity of the sintered silver and copper films was measured using the four-point probe method and an alpha step. As a result, the fabricated Cu/Ag film shows a high electrical conductivity (4.06 μΩcm), which is comparable to the resistivity of bulk copper (1.68 μΩcm). In addition, the fabricated Cu/Ag nanoparticle film shows superior oxidation stability compared to the Cu nanoparticle film. [Not much relevance to acetylide] ---------------------------------------------------------------------- S. Hemmersbach, B. Zibrowius, U. Ruschewitz (1999): "Na2C2 und K2C2: Synthese, Kristallstruktur und spektroskopische Eigenschaften". ''Zeitschrift für anorganische und allgemeine Chemie'', volume 625, issue 9, pages 1440-1446. {{doi|10.1002/(SICI)1521-3749(199909)625:9<1440::AID-ZAAC1440>3.0.CO;2-R}} [Na2C2 and K2C2: Synthesis, Crystal Structure, and Spectroscopic Properties] By the reaction of sodium or potassium solved in liquid ammonia with acetylene and subsequent heating in high vacuum Na2C2 and K2C2 could be synthesised as single phase products. The crystal structures described by Föppl could be confirmed by X-ray and neutron diffraction experiments (K2C2) on powdered samples. Both compounds crystallise in a tetragonal structure (I41/acd, no. 142, Z = 8) which can be described as a distorted variant of the antifluorite-structure type. At temperatures above room temperature (Na2C2: 580 K, K2C2: 420 K) a reversible phase transition (1st order transition) to a cubic modification (Fm 3 m, no. 225, Z = 4) has been observed, analogous to the alkaline earth metal acetylides. This high temperature modification represents an undistorted antifluorite structure with disordered C22– dumbbells. The results of raman- and 13C-MAS-NMR-spectroscopic investigations are in agreement with acetylide dumbbells in the title compounds and allow a comparison to the respective monoalkalimetal and alkaline earth metal acetylides. [GOT IT] 1999-hemmersbach-sodium-potassium-acetylides.pdf ---------------------------------------------------------------------- J. M. Calhoun (1937): "A study of cuprene formation". ''Canadian Journal of Research'', volume 15b, issue 5, pages 208-223. {{doi|10.1139/cjr37b-022}} The copper oxide catalyzed polymerization of acetylene to cuprene has been studied between 230° and 330 °C. by the flow method. The reaction shows an initial induction period at the lower temperatures followed by a rapid rise to a maximum rate and a more gradual decrease. With increase in temperature the induction period becomes shorter, and the maximum rate attained becomes greater. If commenced at 330 °C. the reaction is explosive. Analysis of the exit gas shows considerable ethylene and some free hydrogen, the amounts increasing with the temperature of the reaction. This indicates that the hydrogen split off in cuprene formation does not bear a constant ratio to the amount of cuprene formed. The yield of cuprene based on acetylene reacting is about 85% of theory, which is 4 to 10% lower than values based on a volume contraction of acetylene alone.An exponential equation has been derived which expresses the rate of absorption of acetylene at 290 °C. over a period of 72 hr. under the conditions of the experiment. The equation is integrated to give the quantity of acetylene absorbed at any time. This makes a prediction of yields possible. The heat of polymerization was calculated from the determined heat of combustion of cuprene. Various theories regarding the mechanism of formation and structure of cuprene are discussed, and the photochemical evidence of a chain reaction is supported. ---------------------------------------------------------------------- R. T. Plimpton, M. W. Travers. (1894): "XXVIII - Metallic derivatives of acetylene. I. Mercuric acetylide". ''Journal of the Chemical Society, Transactions'', volume 65, pages 264-269. {{doi|10.1039/CT8946500264}} [Relevant to acetylide but not copper acetylide] ---------------------------------------------------------------------- Franco Cataldo, Vlado Kanazirev (2013): "Synthesis and thermal stability of mercury diacetylide Hg(C≡CH)2". ''Polyhedron'', volume 62, issue , pages 42-50. {{doi|10.1016/j.poly.2013.06.005}} Mercury diacetylide was synthesized and studied by FT-IR spectroscopy, both in the mid and far infrared, and electronic absorption spectroscopy. The spectral data are consistent with the structure H–C≡C–Hg–C≡C–H. Mercury diacetylide is insoluble in common solvents but shows a minimal solubility in ethanol and tetradecane. The thermal stability of mercury diacetylide was studied by thermogravimetry (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). In an open crucible under nitrogen, mercury diacetylide undergoes an exothermal and explosive decomposition releasing 725.6 J/g with an onset temperature of about 250 °C and a peak temperature of 287 °C. The decomposition occurs at a higher temperature in a sealed crucible (onset 326 °C and peak 337 °C). Using the TGA–FT-IR analytical technique it has been found that the deflagration of mercury diacetylide produces elemental carbon, elemental mercury and acetylene. The enthalpy of formation of mercury diacetylide has been determined for the first time. The explosive parameters of mercury diacetylide have been compared with those of other common explosives showing that it is a dangerous and powerful explosive. [GOT IT] 2013-cataldo-synth-therm-stab-mercury-diacetylide.pdf [Relevant to acetylide but not copper acetylide] * Mentions that mercurous acetylide (from acetylene and a water susp of HgAc) is white and too unstable. * Mercuric diacetylide from acetylene and water solns of K2HgI4 or K2Hg(CN)4 in a weakly alkaline conds. * White-yellow powder, insoluble. * Mercuric acetylide is an example of hydrogen-acetylide with terminal bond to metal. * Detonation occurs at 250-290 C with open crucible under N2. * Decomposes in closed crucible at 326-337 C. (Why does open/closed matter?) * Detonation produces acetylene and Hg vapor. * Detonation releases 725.6 J/g ---------------------------------------------------------------------- Kahitibhusan Bhaduri (1912): "[https://ia800708.us.archive.org/view_archive.php?archive=/28/items/crossref-pre-1923-scholarly-works/10.1002%252Fzaac.19100690112.zip&file=10.1002%252Fzaac.19120760119.pdf Cupro-natriumthiosulfat mit Acetylen-Cuproacetylid]" = "Sodium copper thiosulphate with acetylene cupro-acetylide". ''Zeitschrift für anorganische und allgemeine Chemie'', volume 76, pages 419-421. {{doi|}} A solution of sodium thiosulfate was added to a solution of cuproacetate until the liquid became pale green; then acetylene was passed in, and a red precipitate gradually separated, which was filtered off. On washing with water it was found to dissolve easily in it. As no such water-soluble substance had been prepared up to now, attempts were made to prepare and analyze it in the pure state. The substance was found to be insoluble in alcohol, and as both sodium thiosulfate and copper acetate are soluble in this medium, it could be washed out with it. Washing was done first by decantation and then on the filter until the washing alcohol left no residue on evaporation. An amorphous substance of brick-red color was thus obtained. The same substance was obtained by using copper sulfate instead of copper acetate; however, as the sulfate is insoluble in alcohol, this product could not be purified. Although this substance is very soluble in water, it can easily be salted out by any salt. The behavior of saline solution is striking, as it behaves like ordinary water. [??] The precipitation of the substance itself is probably due to this salting out. When heated in air, the substance burns like gunpowder, with the entire mass catching fire at the same time. When heated in a capillary tube to determine the decomposition temperature, it began to decompose at 140°, as indicated by the color change. Heating on a water bath for about 10 hours was sufficient for complete decomposition, while at room temperature (33 C) this took 14 days. The cold aqueous solution was stable for about 1 day. When heated, it decomposed with the evolution of acetylene. The blood-red color of the solution could be made to disappear by adding a little dilute acid, and if this was immediately neutralized with an alkali, avoiding an excess, the original color reappeared; but if some time was allowed to elapse before the alkali was added, this no longer occurred. Potassium iodide gave no precipitate. Ammonium thiocyanate solution produced a white precipitate after a very long time. Alkalis had a peculiar effect: potassium and sodium hydroxide produced a brown precipitate, while ammonia had no effect. After precipitation, the solution had a faint blue color. The precipitate was washed with water and analyzed, and it was found that it contained copper, thiosulfuric acid and acetylene, but no sodium. It exploded more violently than the original substance. [...] 0.2535 g gave 13.6 cc of acetylene at 33°C using the wet method. 0.1273 g of substance gave 3.8 cc of mixed gases when exploded under normal pressure and 0.3162 g gave 11.7 cc of gases when exploded in vacuum at 29.5°C. Taking into account the inaccuracies in the reading and similar circumstances, it can be seen that the gas volumes produced are the same for equal amounts of the substance. It was also noticed that a large amount of water separated on the walls of the tube. [...] The formula that fits the elemental analysis is 5 Na2S2O3 . 5CuSO4 . 5 Cu2C2 . C2H2 . 10 H2O [...] [GOT IT] 1912-bhaduri-water-soluble-sodium-thiosulfate-copper-acetylide-complex.pdf ß ---------------------------------------------------------------------- Ken Judai, Naoyuki Iguchi, Yoshikiyo Hatakeyama (2016): "Low-temperature production of genuinely amorphous carbon from highly reactive nanoacetylide precursors". ''Journal of Chemistry'', volume 2016, article 7840687, pages 1-6. {{doi|10.1155/2016/7840687}} Copper acetylide is a well-known explosive compound. However, when the size of it crystals is reduced to the nanoscale, its explosive nature is lost, owing to a much lower thermal conductance that inhibits explosive chain reactions. This less explosive character can be exploited for the production of new carbon materials. Generally, amorphous carbon is prepared by carbonization of organic compounds exposed to high temperature, which can induce partial crystallization in graphite. In this work, we present a new method in which the carbonization reaction can proceed at a lower annealing temperature (under 150 C) owing to the highly reactive nature of copper acetylide, thus avoiding crystallization processes and enabling the production of genuinely amorphous carbon material. [GOT IT] 2016-judai-low-temp-production-amorphous-carbon-from-acetylides.pdf * Obtains self-assembled copper acetylide nanowires * Result is bulk (not just thin film) amorphous carbon but meso- and micro-porous. * Syntesis with acetylene bubbled though soln of 1 g CuCl in 100 ml 5% ammonia solution for 3 h. * Very slow flow rate (0.05 mL/min) essential to generate nanowires. * Reaction 2CuCl + H2C2 + NH3 --> Cu2C2 + 2 NH4Cl * Raised temp slowly (1 C/min) to 150 C and kept at 150 C for 24 h. * Copper acetylide decomposed by heating at 140 C. * Sulfuric acid used to remove copper. * X-ray diffraction has no peaks indicating negligible crystallinity. * Raman spectrum of result shows broader G and D bands than those of usual activated carbon. * Raman spectrum of result shows no sign of triple bonding. ---------------------------------------------------------------------- V. S. Myl'nikov (1974): "Absorption spectra and structures of copper acetylides". ''Journal of Structural Chemistry'', volume 15, pages 224–228. {{doi|10.1007/BF00746562}}. V. S. Myl'nikov (1974): ''Zhurnal Strukturnoi Khimii'', volume 15, issue 2, pages 244–249. Apparently unavailable online. [GOT IT] 1974-mylnikov-spectra-struct-copper-acetylides.pdf ---------------------------------------------------------------------- Maryne Duval (2021): ''Ligands bidentes pour la synthèse de complexes de cuivre et d'or : étude de leur réactivité''. Doctoral thesis, Univertity of Tolouse, FR. 261 pages. {{HAL|tel-03279808}} [...] Le premier organocuprate synthétisé date de 1859.[29] Il s’agit de l’acétylure de cuivre(I) Cu2C2 préparé par le chimiste allemand Rudolf Christian Böttger en injectant de l’acétylène gazeux dans une solution de CuCl. Il faudra néanmoins attendre près d’un siècle (1952) pour qu’Henry Gilman synthétise et isole les premières espèces d’organocuivreux(I) RCuI ainsi que les lithiens d’alkylcuivre(I) (R2CuLi).[30] [GOT IT] 2021-duval-bidentate-ligand-for-gold-copper-complexes-thesis.pdf ---------------------------------------------------------------------- Rudolf Christian Böttger (1859): "[https://ia800708.us.archive.org/view_archive.php?archive=/22/items/crossref-pre-1909-scholarly-works/10.1002%252Fjlac.18581060204.zip&file=10.1002%252Fjlac.18591090318.pdf Ueber die Einwirkung des Leuchtgases auf verschiedene Salzsolutionen, insbesondere auf eine ammoniakalische Kupferchlorürlösung]" (= "On the effect of illuminating gas on various salt solutions, especially on an ammoniacal copper chloride solution"). ''Justus Liebigs Annalen der Chemie'', volume 109, issue , pages 351–362. [GOT IT] 1859-boettner-acetylene-on ammoniacal-copper-chloride-soln.pdf * Discovery. ---------------------------------------------------------------------- (): "". '''', volume , issue , pages . {{doi|}} Revue universelle des mines, de la métallurgie, de la mécanique des travaux publics, des sciences et des arts appliqués à l'industrie: organe de l'Association des Ingénieurs Sortis de l'Université de Liège, A.I.Lg. : revue trimestrielle. Jg. 15. 1871, 2, Volume 30 [https://books.google.com.br/books?id=3JhPAAAAcAAJ&ots=I6AysJ4wbm&dq=%22acetylure%20de%20cuivre%22&lr&pg=PA148 ] EXPLOSION PRODUITE PAR L'ACETYLURE DE CUIVRE DANS UN TUYAU A GAZ Le 21 avril dernier l'appareilleur Rotti ayant, au moyen d'une lime triangulaire, scié, jusqu'à moitié de son diamètre, un tuyau en cuivre rouge de 0,010 m de diamètre intérieur, servant à la distribution du gaz à la station de Liége, venait de retirer l'outil lorsqu il se produisit une explosion comparée un coup de fusil par l'ouvrier qui fut brûlé au visage. Un fait semblable s'était produit la veille, avec moins d'intensité toutefois. L'ouvrier, qui n'avait pas été atteint, n'en fit pas rapport. Quelques uns des tuyaux voisins ayant été démontés, on les a trouvés tapissés d'enduits noirâtres abondants; ils présentaient d'ailleurs des traces évidentes de corrosion par des condensations fortement ammoniacales. M. le professeur Chandelon, qui a bien voulu, à la demande de M. l'ingénieur en chef Cambrelin, examiner la matière noirâtre, a consigné le résultat de ses recherches dans la lettre reproduite ci après : /A Monsieur Cambrelin, ingénieur en chef à l'administration des chemins de fer, postes et télégraphes./ Liége, le 21 mai 1870. J ai examiné la matière détonnante que M l'ingénieur Docteur a recueillie dans un tuyau à gaz en cuivre rouge et à laquelle on attribue l'explosion qui s'est produite à la station des Guillemins, le 21 avril dernier et a brûlé au visage l'aide appareilleur Rotti qui, en ce moment, limait et réparait ce tuyau. Cette substance se présente sous la forme d'une poudre noire parsemée de petites écailles d un brun foncé et répandant une odeur de gaz éclairant très prononcée. Placée sur une enclume et frappée avee un marteau, elle ne détonne point; projetée sur une plaque métallique chauffée à environ 180 degrés, ou bien touchée avec un fer rouge, elle brûle en lançant des étincelles. L'eau n'a pas d'action sur elle, mais l'acide chlorhydrique la décompose immédiatement en donnant lieu à une effervescence due au dégagement d'un gaz odorant et combustible. Ce gaz forme, dans la solution ammoniacale de protochlorure de cuivre, un précipité rouge marron, réaction qui constitue le caractère distinctif de l'acétylène C2 H2. La solution chlorhydrique d'où l acétylène s'est dégagé a donné toutes les réactions du cuivre, de sorte que la matière déposée dans le tuyau est l'acétylure de cuivre (HC2-Cu)2O, composé qui fait explosion par choc et qui, chauffé, détonne entre 95 et 120 degrés, en produisant de l'eau, du cuivre, du carbone, de l'acide carbonique, et des traces d'oxyde de carbone. L acétylène existe dans le gaz de houille, et lorsqu on fait passer un courant d'acétylène à travers une solution d oxyde de cuivre dans l'ammoniaque, il est absorbé, en grande partie brûlé, et il se dépose sur les parois du vase une matière charbonneuse, mélangée d'une petite quantité d acétylure de cuivre. Feu M. Boetger, en 1859, a signalé la formation de composés explosibles par l'action du gaz de l'éclairage sur certaines solutions salines, et, notamment sur une solution ammoniacale de protoxyde de cuivre. Le professeur Gorrey a observé à New York une combinaison analogue qui avait tué un ouvrier occupé à enlever dans une maison des tuyaux de conduite de gaz de l'éclairage. Cet ouvrier s'étant avisé de placer dans sa bouche l'extrémité d'un des tuyaux de cuivre et d'y souffler avec beaucoup de force, il y eut à l'instant même une forte détonation par laquelle la bouche et les organes voisins furent tellement déchirés que les blessures causèrent la mort au bout de quelques heures. Ce qui précède explique parfaitement l'accident survenu aux Guillemins, et, comme moi, M. l'ingénieur en chef, vous serez, je pense, d'avis qu'on devrait défendre l'emploi du cuivre pour la confection des tuyaux d'appareillage. Agréez, M. l'ingénieur en chef, l'assurance des mes sentiments les plus distingués. J. Chandelon. (Extrait des /Annales des travaux de Belgique/.) ---------------------------------------------------------------------- Georges Pellissier (1897): ''[https://books.google.com.br/books?id=KywIAAAAIAAJ&pg=PA30 L'éclairage à l'acétylène: historique, fabrication, appareils, applications, dangers''. 237 pages. Cette réaction est très sensible ; elle permet de déceler la présence de 1/200e de milligramme d acétylène mélangé à l'hydrogène et 1/100e de milligramme en présence de l'air. [...] M Lewes a reconnu que le gaz sec et pur est sans action sur les métaux, mais qu'étant humide, il attaque vivement le cuivre et plus lentement les alliages de cuivre. M. Bullier a fait remarquer que la formation de l'acétylure ou acétylénure de cuivre n'est pas aussi simple qu'on semble le supposer ; pour que ce corps puisse prendre naissance, il faut que l'acétylène se trouve en présence d'un sel de cuivre au minimum d'oxydation, c'est à dire d'un sous-sel de cuivre, et de plus, en présence d un excès d'ammoniaque. Nous avons vu plus haut que Davy avait obtenu du carbure de potassium et Wöhler du carbure de calcium En 1866 Berthelot obtint du carbure de sodium ou acétylure de sodium par le procédé suivant il faisait chauffer légèrement dans une atmosphère d acétylène du sodium métallique ce corps se gonfle en absorbant l acétylène et forme le composé C H Na Lorsque la température est portée au rouge sombre le sodium détruit l acétylène et il se forme une masse noire d apparence charbonneuse qui est du carbure de sodium C2Na2 mis en présence de l eau ce corps se décompose et il se dégage de l acétylène * Sensitivity of the acetylene detection. * Claim that acetylene pure and dry does not attack metals. Must include water vapor and ammonia, and the copper must be partly oxidized. * Wöhler discovery of sodium carbide. ---------------------------------------------------------------------- David Walt, Harry Kroto (2010): "[https://www.chemistryworld.com/opinion/comment/3005172.article Harry Kroto gets hot under the collar on the subject of so-called carbyne]". ''RSC Chemistry World'', Comment, 28 October 2010. [No DOI?] [GOT IT] * Refutes the existence of solid carbyne because it would explosively rearrange into other forms of carbon. ---------------------------------------------------------------------- Anna Ghiretti-Magaldi, A. Giuditta, F. Ghiretti (1957): "A study of the cytochromes of Octopus vulgaris lam". ''???'', volume 66, issue ??, pages 303-307. {{doi|???}} [Not related to copped acetylide] * Blood pigment of octopus is copper-based haemocyanin, not iron-based haemoglobin. * Yet the paper finds active iron-based cytochrome a, a3, b, and c in octopus muscle. [GOT IT] 1957-magaldi-cytochromes-found-in-octopus-muscle.pdf ---------------------------------------------------------------------- Richard Sidney-Curtiss, Earle K. Stracham (1911): "Condensation in the mesoxalic ester series". ''???'', volume ???, issue ???, pages 396-400. {{doi|???}} [GOT IT] 1911-curtiss-mesoxalic-ester-diethyl-oxomalonate.pdf [Relevant for mesoxalic acid] * Prepared from diethyl dihydroxymalonate by dehydration with P2O5. * MP below -30 C. * BP 122 C at 40 torr, 117 C at 31 torr. * Diethyl oxomalonate is a green oil, slightly more yellow than the dimethyl ester. * Density 1.119 at 20 C. * Reacts even at low temperature with HCl and C=O is replaced by CCl(OH), plus some HCl is absorbed. * The product is a colorless syrup, MP between -29 C and -10 C, losing HCl, decomposed by water. * Ditto with HBr; product melts between -21 C and -15 C. ---------------------------------------------------------------------- Beatriz Gil-Hernández and Joaquín Sanchiz (2021): "Synthesis, structure and magnetic properties of a cobalt(II) mesoxalate 1D coordination polymer". ''Zeitschrift für anorganische und allgemeine Chemie'' (= ''Journal of Inorganic and General Chemistry'', volume 647, pages 485 – 489. {{doi|10.1002/zaac.202000431}} [GOT IT] 2021-hernandez-cobalt-mesoxalate-polymer.pdf * Gives CO(OH)2 instead of C=O for the middle carbon. ---------------------------------------------------------------------- Rosaria Ciriminna, Mario Pagliaro (2003): "One-Pot Homogeneous and Heterogeneous Oxidation of Glycerol to Ketomalonic Acid Mediated by TEMPO". ''Advances in Synthesis and Catalysis'', volume 345, issue 3, pages 383-388. {{doi|???}} [GOT IT] 2003-ciriminna-ketomalonic-acid-from-glycerol.pdf * Gives formula with C=O not C(OH)2. ---------------------------------------------------------------------- (): "". '''', volume , issue , pages . {{doi|}} ---------------------------------------------------------------------- (): "". '''', volume , issue , pages . {{doi|}} ---------------------------------------------------------------------- (): "". 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