When bromine was used to bromization reaction with 4-acetyl-guaiacol,the product bromide incompletely or super bromide partial,and the selectivity was poor.

使用單質(zhì)溴與4-乙酰基愈創(chuàng)木酚進(jìn)行溴化反應(yīng)時(shí)熟妇精品视频，產(chǎn)物溴化不完全8X视频导航，或者局部過量的溴化狼友官网首页二，且選擇性較差又粗又长又硬又爽的少妇毛片。

In China, We are also the biggest manufacture of Acetyl bromide , Propionyl bromide, Bromoacetyl bromide, 2-bromopropionyl bromide,-1,4-dibromobut-2-ene and Phosphorus tribromide etc.

擁有一支以海歸博士欧美性爱教学视频、碩士為主的研發(fā)隊(duì)伍和專業(yè)外貿(mào)營銷人才。公司首批通過ISO14001國際環(huán)境管理體系認(rèn)證黄色网站免费激情啪啪啪，并通過IS09001質(zhì)量管理體系認(rèn)證欧美一级免费网址。

It is found that when the molar ratio of sulphoxide,pyridine and acetyl bromide is 1∶0.6∶0.4,the catalytic effect on the ring-enlargment is the best,and the yield and purity of the final product can reach 76% and 97% respectively at a pH of 1.8 in toluene under refluxing for about 3.5h.

通過正交實(shí)驗(yàn)可得出以下結(jié)論：當(dāng)N，N′-雙脲-亞砜為2.5∶1黄色在线91AV，乙酰溴-亞砜為0.4∶1天天狠天天添日日拍，吡啶-乙酰溴為1.5∶1，回流時(shí)間為3.5h国产暖暖在线播放，酸化pH值為1.8時(shí)中文字幕毛片网址，擴(kuò)環(huán)反應(yīng)結(jié)果最好，總收率可達(dá)76%怡红院成永久免费人视频新的，純度97%以上久热精品视频。

For example, pulverized wood samples can be treated with acetyl bromide in acetic acid, and the absorbance of the resulting solution at 280 nm can be compared with the absorbance obtained from known lignin standards.

例如，將木屑樣品在乙酸環(huán)境下與乙酰溴進(jìn)行反應(yīng)www.色综合,com，再將280納摩爾所得溶液的吸收率與已知的木質(zhì)素標(biāo)準(zhǔn)吸收率進(jìn)行比較。

Penicillin G sulphoxide is esterified by N,N′-bistrimethylsilyl urea under the temperature 55℃ with a molar ratio 2.5∶1 between BSU and sulphoxide,and the ester obtained is ring-enlarged in the toluene under refluxing with the exist of catalyst-pyridine acetyl bromide.

摘 要 本文在制得青霉素G亞砜的基礎(chǔ)上成人影院蜜桃传媒在线播放，完成了重排酸的擴(kuò)環(huán)反應(yīng)中国老熟女BBWXXXX，重點(diǎn)探討了擴(kuò)環(huán)反應(yīng)的最優(yōu)化條件。青霉素G亞砜與N69视频在线，N′-雙脲在55℃下反應(yīng)日本AAAAA级婬片A片AAAAAA，得到亞砜的酯化物。