Crotonaldehyde, stability

Copper amine azide Copper tetramine nitrate Crotonaldehyde, stabilized Cyanogen bromide Cyanuric triazide... 

SYNS 2-BUTENAL CROTONALDEHYDE, stabilized (DOT) CROTONIC ALDEHYDE KROTON-ALDEHYD (CZECH) (3-METHYLACROLEIN RCRA WASTE NUMBER U053... 

CHEMICAL PROPERTIES highly reactive polymerizes and copolymerizes readily dimerizes to 4-vinylcyclohexene reacts vigorously with phenol, chlorine dioxide, copper and crotonaldehyde stabilization with o-dihydroxybenzene FP (-76°C, -105°F) LFL/UFL (2.0%, 11.5%) AT (420°C, 788°F). 

Synonyms 2-Butenal 2-Butenaldehyde Crotonal Crotonaldehyde stabilized Crotonic acid aldehyde... 

Crotonaldehyde stabilized. See Crotonaldehyde Croton bark oil Croton cascarilla Croton cascarilla oil Croton eluteria Croton eluteria oil Croton extract. See Cascarilla oil Crotonic acid... 

Crossed reactions of the two aldehydes under phase-transfer catalytic conditions with the intermediate thioacetates, which can be isolated under controlled reaction conditions [14], leads to the formation of three products [13], as result of retro-Michael reactions (Scheme 4.18). In the case of the reactions involving crotonaldehyde, the major product results from the reaction of the aldehyde with the released thiolacetic acid, with lesser amounts of the expected crossed reaction products (Table 4.23). In contrast, the reaction of acrolein with the thioacetate derived from crotonaldehyde produces, as the major product, the crossed cycloadduct. These observations reflect the relative stabilities of the thioacetates and the relative susceptibilities of acrolein and crotonaldehyde to the Michael reaction. 

The results presented here correspond to a series of tin-modified platinum catalysts prepared by SOMC/M techniques, which have the characteristics shown in entries 1, 6, 7 and 13 in Table 6.4. Figure 6.10 shows the variation of crotonaldehyde conversion as a function of time for two successive reaction cycles. A characteristic of these catalytic systems is their stability-only a slight flattening is observed for the Pt/Si02 catalyst. The presence of tin seems to improve this stability. Completely reproducible behavior is observed for both cycles, which is an important result mainly for the PtSn-OM system, which contains butyl groups anchored to the surface. 

Trans-2-Butenal (trans-Crotonaldehyde). Pitts and coworkers (2,58) investigated the photolysis of trans-crotonalde-hyde in the gas phase to correlate the structural effects on photodecomposition and reactivity of a, (5-unsaturated aldehydes. As in the case of acrolein, this molecule showed an unusual stability, except polymerization being the only significant reaction at 265-254 nm and 25°C (2). Some reactions giving... 

Lewis acid complexes of -substituted a, 3-unsaturated ketones and aldehydes are unreactive toward alkenes. Crotonaldehyde and 3-penten-2-one cannot be induced to undergo ene reactions like acrolein and methyl vinyl ketone. The presence of a substituent on the -carbon stabilizes the enal- or enone-Lewis acid complex and stericdly retards the approach of an alkene to the -carbon. However, Snider et al. have found that a complex of these ketones and aldehydes with 2 equiv. of EtAlCk reacts reversibly with alkenes to give a zwitterion (22). This zwitterion, which is formed in the absence of a nucleophile, reacts reversibly to give a cyclobutane (23) or undergoes two 1,2-hydride or alkyl shifts to generate irreversibly a p, -disubstituted-a,P-unsaturated carbon compound (24). 

Several solid-liquid two-phase systems have been described powdered KOH in THF or DMF, Ba(OH)2 in moist dioxane, K2CO3 in water or D2O or anhydrous solvents, Na2CO3 in moist THF and NaHCO3 in water. The system using aqueous 6-9 M K2CO3 solution appears as the most promising. This new technique provides routinely good yields of functional olefins from aldehydes (Scheme 6.48). It allows the use of functional aldehydes without protection or aqueous stabilized solutions of unstable pure aldehydes without previous isolation (formaldehyde, crotonaldehyde). 

Activity and selectivity of monometallic Ag catalysts can be controlled by the preparation conditions leading to micro- and meso- to macroporous catalysts which are active and selective in the hydrogenation of crotonaldehyde. In Ag catalysts modified by a second metal, bimetallic sites exhibiting surface polarity and Ag particles in close contact with a partially reduced early transition metal or a rare earth element, or Ag species stabilized and incorporated in these oxides were concluded to be the active species in the working state of these catalysts. Simultaneous introduction of both metals during the sol-gel process under optimized hydrolyzing conditions could further increase the metal-promoter interaction and lead to well-tailored new hydrogenation catalysts. 

Substantial stabilization is brought about by the alternating arrangement of the C=C and C—O groups in crotonaldehyde. 

BUTADIENO (Spanish) (106-99-0) Flammable gas (flash point — 105°F/—76°C). Self-reactive. In absence of an inhibitor, forms heat-, shock-, and impact-sensitive peroxides with air. Stabilize with fert-butyl catechol or other inhibitor and maintain levels at all times. Fires, explosions, or hazardous polymerization may result from contact with strong oxidizers, copper, high copper alloys, chlorine dioxide, crotonaldehyde, strong acids, nitrogen dioxide, ozone, phenol, sodium nitrite, or polymerization initiators such as azobisisobutylonitrile. 

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