Acrylates results

A significant step towards commercial success came with a discovery in the late 1950s by E. Ulrich at 3M when he found that copolymerization of hydrogen bonding monomers, like acrylic acid with alkyl acrylates resulted in cohesively strong, yet tacky materials [63]. Since then, newer developments in such areas as polymer crosslinking, and the synthesis and copolymerization of new monomers, have led to a rapid penetration of acrylics throughout the PSA industry. 

Improvement to the Reformatsky reactions was achieved (53) by the use of a highly activated zinc - silver couple dispersed on the surface of graphite. T reatment of protected aldono-1,4-lactones 10b or 25b and 1,5-lactones 51a or 51b with a Reformatsky reagent prepared from a-haloesters or alkyl 2-(bromomethyl)acrylates resulted in the formation of the corresponding 3-or 4-glyculofuranos (or pyranos)onates 49a,b-50a,b, or 52a,b, respectively, under mild conditions (— 40 ° to 00) and in very good yields. Ethyl 2-deoxy-2-fluoro (and 2-bromo)-a-D-wa o-3,6-furanos-3-octulosonate derivatives were also obtained. 

Ionizing radiation on poly(alkyl acrylates) results in cross-linking efficiencies, which are sensitive to the structure of the alkyl ester group."... 

Jeio and Kalad4 have developed another, more efficient, route to 1-hydroxymethylpyrrolizidine. A two-step Michael condensation of nitromethane with ethylmethoxycrotonate and then with ethyl acrylate resulted in ethyl j8-methoxymethyI-y-nitropimelate (74). The latter yields 2-(2-carboethoxy-l-methoxymethylethyl)pyrrolid-5-one (75) on hydrogenation over Raney nickel and 2-(3-hydroxy-1-... 

Iridium-catalyzed reductive coupling of acrilates and imines has been reported to provide trans (3-lactams with high diastereoselection [142], The use of electron-deficient aryl acrylates resulted in improved product yields. The mechanism, proposed by the authors, started from an in situ generated iridium hydride reacting with the acrilate to provide an iridium enolate that, then, reacted with the imine to give a (3-amido ester. Subsequent cyclization furnished the p-lactam and an iridium alcoxide. 

During the course of the Baylis-Hillman-reaction two stereocenters are formed, one of which remains in the Baylis-Hillman-product. An obvious concept for the development of an asymmetric version of the reaction represents the use of an enantiomerically pure acrylic acid derivative. The use of enantiomerically pure menthyl acrylates resulted, but only in certain cases, to respectable diastereomeric excesses [21]. A significant improvement was reported in 1997 by Leahy and coworkers who used the Oppolzer-sultame as a chiral auxiliary in DABCO-catalyzed Baylis-Hillman-reactions (Scheme 2) [22]. In this reaction, the... 

Bulky crosslinks or side-groups in the network chains, e.g., dendritic wedges [73], may also influence molecular mobility and viscoelastic properties of polymer networks. For example, UV curing of difunctional acrylates results in the formation of zip-like network junctions, which may be regarded as extreme cases of bimodal networks [52], Results obtained with the NMR T2 relaxation method agree well with those of mechanical tests... 

Reaction of the pyridyl methylamine (45) with methyl acrylate results in Michael addition of 2 equiv of the reagent to afford the diester (46). 

The possibility that metallocenes might function as Lewis acids in Diels-Alder reactions was probed with ferrocenium hexafluorophosphate [184]. The answer is affirmative the cycloadditions studied include methacrolein, crotonaldehyde, and methyl vinyl ketone as dienophiles and butadienes and cyclopentadienes as diene components. Yields are in the range 60-80 % with reaction times of 3-36 h at 0 to 20 °C. Fair to good yields were also obtained in reactions of isoprene and cyclopentadiene with acrolein and methyl vinyl ketone in the presence of 1 % [Pd(PPh3)2(MeCN)2](BF4)2 (in CH2CI2, room temperature). Methyl acrylate resulted in low yields, and chiral modification with (5)-BINAP is reported to give the cycloadducts with modest enantioselectivity [164]. 

The peaks from the pyrogram of poly(ethylene-co-methyl acrylate) resulting from the ... 

The use of MAD in [4+2] cycloaddition of cyclopentadiene with chiral acrylate resulted not only in greater diastereoselectivity but also greater exo-selectivity, although to a small degree, than ofher ordinary Lewis acids (Scheme 6.39) [61]. 

Like the foregoing technique, this one may offer the advantage of not producing the adipic acid from benzene, but from olefins. The methyl acrylate results from the oxidation of propylene to acrylic acid, which is then esterified by methanol ... 

The photodegradation of poly(n-butyl acrylate) results In the loss of the n-butyl ester side group to yield crosslinks, carboxylic acid groups, keto and aldo groups, and volatile products including butanol and butene. 

By far the acrylates are the monomers of choice in UV curable systems. Not only do they cure at extremely rapid rates compared to other monomer systems (acrylic > methacrylic > vinyl > allylic), but they are also available in a wide range of structures which are monofimctional, difunctional, trifunctional, and tetrafunctional. Additionally, as shown in the oligomer section, acrylates can be used to derivatize oligomers or pre-polymers. Commonly in UV curable formulations it is necessary to use a number of monomers in order to achieve a balance between speed of cure and properties of the final film. It is not unheard of to use four or five monomers in a single UV curable formulation. For instance, tri- and tetra-functional acrylates result in highly crosslinked films when incorporated into UV curable resins however, they severely limit the extent and rate of the curing process. Thus, one often combines a tetrafunctional acrylate to increase crosslink density with a mono and/or difunctional acrylate to increase the cure rate. 

Cross-metathesis of two different alkenes to give an acyclic alkene is complicated by the possible formation of not only the desired cross-metathesis product, but also self-metathesis products, each as a mixture of alkene isomers. However, some alkenes are amenable to efficient cross-metathesis to give the desired substituted alkene. This is particularly the case with alkenes that are slow to homod-imerize, such as a, -unsaturated carbonyl compounds or alkenes bearing bulky substituents. Hence, cross-metathesis of methyl acrylate with an alkene proceeds efficiently (2.116). The ruthenium catalyst reacts preferentially with the more electron-rich alkene 98, which then undergoes cross-metathesis with the acrylate or self-metathesis with another molecule of the alkene 98. The latter reaction is reversible and hence a high yield of the desired substituted acrylate results over time. The use of 1,1-disubstituted alkenes as partners in cross-metathesis provides a route to trisubstituted alkenes. This chemistry is therefore a useful alternative to conventional syntheses of alkenes, such as by the Wittig reaction. 

Conjugate addition of this anion to tert-butyl acrylate, results in the formation of an anion on the a position of the tert-butyl ester. 

A similar synthetic strategy was used to attempt the preparation of block copolymers of poly(styrene-co-t-butyl acrylate). In an endeavor to prepare a poly(t-butyl acrylate) macroinitiator (11), t-butyl acrylate was polymerized using 1-phenyl-l-(2, 2, 6 ,6-tetramethyl-l -piperidinyloxy)-ethane (4) at a temperature of 130°C (Scheme 4). However, in stark contrast to the TEMPO mediated polymerization of styrene, the polymerization of t-butyl acrylate resulted in polymers with broad polydispersities (e.g. M = 9415 PD = 2.2). As a result these poly (t-butyl acrylate) macroinitiators were too ill-defined for the preparation of well-defined block... 

A bromine-terminated monofunctional poly(rerr-butyl acrylate) resulting from ATRP of rBA catalyzed by the CuBr/At, At,At, iV, lV"-pentamethyldiethylenetriamine (PMDETA) system (initial mole concentration ratios tBA methyl bromopropionate (MBrP) CuBr PMDETA CuBr2 = 50 1 0.5 0.525 0.025, 25% acetone, 60°C conversion = 96% after 6.5 h) was used as macroinitiator for block copolymerization with styrene (St) with the initial mole concentration ratios of St P(rBA) CuBr PMDETA = 100 1 1 1 at 100°C (conversion 94%). The monofunctional bromo-terminated copolymer P(rBA)-A-P(St) formed was subsequently used as a macroinitiator for a further copolymerization with methyl acrylate (MA). The polymerization was also catalyzed by CuBr/PMDETA (initial concentration ratios MA P(rBA-i>-P(St) CuBr PMDETA = 392 1 1 1), under high dilution in toluene and reached 23% monomer conversion after 3.5 h at 70°C. The experimental molecular weight (M ) of the resulting triblock copolymer P(tBA)-fo-P(St)-fr-P(MA) was 24,800 with a PDI = 1.10. Calculate the theoretical M to compare with the experimental value. 

In contrast, the extension of this promising polymerization process to acrylates proved to be more challenging than expected. Indeed, synthesis of random copolymers of styrene and low amounts of -butyl acrylate provided high yields and narrow molecular mass distributions, but increasing the level of acrylate resulted in higher polydispersities and a lowering of conversion (Table 7). Additionally to random copolymerization, this method was applied for the synthesis of a poly(styrene- )-(styrene-cu-n-butyl methacrylate) block copolymer [265],... 

Organocobalt porphyrin complexes have also yielded useful mechanistic information. The reactions of (tetrakis(p-methoxyphenyl)porphyrinato)cobalt(II) ((TAP)Co(II)) with radicals derived from dialkylazo thermal initiators with acrylic monomers provide evidence for the intermediacy of Co(III)-H species in CCTP. Reaction of (TAP)Co (II) with tertiary alkyl radicals, for example, as derived from AIBN in the presence of monomers that form stable Co-alkyl complexes, such as methyl acrylate, results in quantitative formation of Co(III)-alkyl. Whereas with monomers leading to tertiary C-Co bonds, such as MMA, the Co (II) is very much a spectator as normal polymerization ensues. Thermodynamic and activation parameters have been measured for the dissociation of (TAP)Co(III)-C(CH3)2CN to Co(II) and organic radical in solution as a probe into CCTP mechanism by low-spin Co(II). ... 

Optical lithography can be used to transfer the patterns from the mold onto the substrate. In one example, a sequential application of polymer molds engraved with microscale and nanoscale features with a UV-curable resin of polyurethane acrylate resulted in a surface with two-tier roughness morphology. A subsequent treatment with trichloro(lH,lH,2H,2H-perfluorooctyl) silane rendered the surface superhydrophobic and displayed both the Cassie—Baxter and the Wenzel state 0eong et al., 2009). 

Analogous ring expansion via P-fragmentation of cyclobutanoxyl radicals derived from the photoadducts between a- or P-naphthyl trimethylsilyl ether and acrylonitrile or methyl acrylate resulted in the formation of a benzohomotropone after treatment with a base. 

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