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Other Modification Processes
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
In their work, acylation was undertaken with benzoyl chloride and carbanilation was performed with phenyl isocyanate, both at 70°C, with the product being isolated after precipitation with methanol and water (Xie et al., 2007). Shen et al. (2017) were pre-treated wood fibres with 1 butyl-3-methylimidazonium chloride at 125°C, which significantly reduced the crystallinity of the fibres and extracted some of the lignin (up to 34%), prior to the reaction with acetic anhydride in the presence of toluene and pyridine (the latter to counteract acidic by-products). An increase in wood content in the IL solution was found to reduce the effectiveness of the reductions in crystallinity and lignin levels, but the higher wood levels led to higher acetylation levels as well as a lower moisture sorptivity.
Organic Catalysis by Clay-Supported Reagents
Published in Benny K.G. Theng, Clay Mineral Catalysis of Organic Reactions, 2018
EPZ10 and other Envirocats such as EPZG (clay-supported ferric chloride) and EPIC (clay-supported polyphosphoric acid) can also catalyze the Friedel−Crafts acylation of substituted benzenes with acyl chloride or acid anhydride under microwave irradiation (Bandgar and Kasture 2000b). Similarly, Ghatpande and Mahajan (2005) used Envirocat EPZG to synthesize various benzophenones by reacting substituted benzenes with benzyl chlorides. Envirocat EPZG could also promote the conversion of aldoximes into nitriles (Bandgar et al. 1995), the selective acetalization of aldehydes and ketones (Bandgar and Gaikwad 1998), the transesterification of β-keto esters with various alcohols (Bandgar et al. 2001), and the synthesis of N-benzyl substituted amides from benzyl alcohols and substituted nitriles (Veverková and Toma 2005). This commercial catalyst is equally efficient in mediating the synthesis of imines (from aldehydes and primary amines) and enamines (from ketones and secondary amines) as well as the benzoylation of various benzene, naphthalene, and thiophene derivatives (with benzoyl chloride or benzoic anhydride) under solvent-free conditions and microwave irradiation (Varma and Dahiya 1997a; Veverková et al. 2000).
Atomic, Molecular, and Optical Physics
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Name Diethylene glycol dimethyl ether Dipropyl sulfide Diisopropyl sulfide Hexylamine Dipropylamine Diisopropylamine Triethylamine Triethanolamine 2,3,4,5,6-Pentafluorotoluene Benzoyl chloride (Trichloromethyl)benzene (Trifluoromethyl)benzene Benzonitrile Benzaldehyde Benzoic acid p-Bromotoluene o-Chlorotoluene m-Chlorotoluene p-Chlorotoluene (Chloromethyl)benzene o-Fluorotoluene m-Fluorotoluene p-Fluorotoluene Benzamide o-Nitrotoluene m-Nitrotoluene p-Nitrotoluene Toluene o-Cresol m-Cresol p-Cresol Benzyl alcohol Anisole Benzylamine o-Methylaniline m-Methylaniline p-Methylaniline N-Methylaniline 2,3-Dimethylpyridine 2,4-Dimethylpyridine 2,5-Dimethylpyridine 2,6-Dimethylpyridine 3,4-Dimethylpyridine 3,5-Dimethylpyridine Dicyclopropyl ketone 1-Heptene trans-3-Heptene Cycloheptane Methylcyclohexane cis-1,2-Dimethylcyclopentane trans-1,2-Dimethylcyclopentane 1-Heptanal 2-Heptanone 3-Heptanone 4-Heptanone 5-Methyl-2-hexanone 2,4-Dimethyl-3-pentanone 1-Methylcyclohexanol Heptane 1-Heptanol
Synthesis and phase behaviour of a class of comb-like cholesteric azobenzene liquid crystalline polymers
Published in Liquid Crystals, 2023
Zi-Yun Zhang, Jiang-Tao Sun, Chun-Yang Li, Ya-Ping Liu, Zhong-Xin Ge, Ying-Gang Jia, Mei Tian, Dan-Shu Yao
First, 62.0 g (0.35 mol) of compound B were weighed into a 250 mL flask and 80 mL of thionyl chloride and 3–4 drops of DMF were added. The solution was stirred at room temperature for 2 h and refluxed at 65°C for 6 h. The excess thionyl chloride was removed by distillation under reduced pressure to obtain a brownish-yellow liquid 4-(allyloxy)benzoyl chloride. Then, 50 mL of THF and 40 mL of pyridine were measured and mixed with 18 mL of lactic acid. Another 20 mL of THF was mixed with 19.6 g of 4-(allyloxy)benzoyl chloride. The 4-(allyloxy)benzoyl chloride was added drop by drop to the mixture of lactic acid at room temperature. After the dropwise addition, the temperature was controlled at about 60°C and refluxed for 24 h. After the reaction stopped, the coarse product was poured into cold water and then filtered and dried on glassware to obtain the final product powder (C).
Liquid crystal elastomers containing azobenzene homologues as crosslinkers—synthesis and characterization
Published in Liquid Crystals, 2023
Zi-yun Zhang, Zhong-Xin Ge, Yi-Min Wang, Jiang-Tao Sun, Ying-Gang Jia, Mei Tian, Dan-Shu Yao
First, 100.0 g of p-hydroxybenzoic acid was weighed in a 500 mL three-necked flask and 200 mL of ethanol was added to completely dissolve it. One hundred millilitres of the aqueous solution containing potassium hydroxide (44.0 g) and potassium iodide (1.5 g) were added and stirred until clarified. 87.6 mL bromopropene was then added and refluxed for 10 h to give white crystals of 4-(allyloxy)benzoic acid. Fifty-gram 4-(allyloxy)benzoic acid was added in a 500 mL flask. Seventy millilitres of thionyl chloride was added rapidly, stirred at room temperature for 1 h, and raised the temperature to reflux for 3 h. The product was a pale yellow liquid, 4-(allyloxy)benzoyl chloride. Then 75.0 g of hydroquinone was weighed in a flask and 150 mL THF and 27 mL pyridine were added to completely dissolve it. Stirring at room temperature, 61.6 g of 4-(allyloxy)benzoyl chloride was slowly added dropwise. The reaction was carried out at room temperature for 2 h and refluxed for 8 h. After the reaction, the reaction solution was completely poured into water and soaked for 24 h. A white precipitate was formed. The precipitate was filtered out, washed with hot water for many times, and recrystallised in ethanol to obtain a white solid A.
The cholesteric and TGB phases under the applied electric field
Published in Liquid Crystals, 2021
Vladimíra Novotná, Sergey Stulov, Věra Hamplová, Martin Cigl, Damian Pociecha
Target materials were synthesised as shown in Scheme 1. Starting methyl 4-hydroxy-3-methylbenzoate (1) was synthesised as described previously [29]. For our purposes, it was alkylated by the n-alkylbromides of appropriate lengths. Methylester group was hydrolysed under basic conditions and the liberated alkoxybenzoic acids were then converted into their acyl chlorides 2a and 2b by the reaction with oxalyl chloride. The chiral part of the molecule was synthesised from benzoyl chloride 3, prepared as described in Ref [30]., which was reacted with (S)-dodecyl lactate (4) in the presence of pyridine and the methoxycarbonyl protective group was cleaved by aqueous ammonia giving the hydroxy-ester 5. To introduce the second benzene ring, the chiral hydroxy-ester 5 was reacted with benzoyl chloride 3 again and the protected hydroxy group liberated analogously, giving rise to hydroxy-ester 6. In the last step of the synthesis, the chiral hydroxy-ester 6 was reacted with alkoxybenzoyl chlorides 2a or 2b in the presence of 4-(N,N-dimethylamino)pyridine yielding the target materials 8KDDL(S), 10KDDL(S) and 12KDDL(S). Racemic material 12KDDL(rac) was synthesised by the same synthetic protocol, using racemic dodecyl lactate. All synthetic details and chemical analyses are provided in Supplemental file. For example, chromatograms of HPLC enantiomer separation are shown in Figure S1.