Publication number: 20240109835
Abstract: A method for preparing-3,3?-diaminobenzidine, the method comprising the following steps: subjecting 4,4?-biphenol and N,N-dimethylsulfamoyl chloride to an esterification reaction in a specified solvent at 40-70° C. to obtain 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a first intermediate; subjecting the 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to a chlorination reaction with a chlorinating reagent under acidic conditions to obtain 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a second intermediate; subjecting the second intermediate 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to an ammonolysis reaction with anammoniation reagent in the presence of a combined catalyst to obtain a crude product of 3,3?,4,4?-tetraaminobiphenyl, wherein the combined catalyst is a mixture of proline, a cuprous salt and a phase transfer catalyst; and subjecting the crude product of 3,3?,4,4?-tetraaminobiphenyl to a post-treatment to obtain a purified 3,3?,4,4?-tetraaminobiphenyl product.
Type:
Application
Filed:
January 12, 2022
Publication date:
April 4, 2024
Applicants:
HUBEI HUIDA HIGH-TECH CO., LTD., BORUN HIGH-TECH CO., LTD.
Inventors:
Yun LING, Yongfang LI, Kun WANG, Lizhu CHEN, Wei YIN, Jinying ZHANG
Patent number: 11313192
Abstract: The present invention discloses a method for lowering an oil pipe in a gas well without well-killing, a soluble bridge plug and a material preparation method thereof, wherein, the method comprises the steps of: lowering a bridge plug in a wellbore such that the bridge plug blocks the wellbore at a predetermined location in the wellbore; injecting water in the wellbore after the pressure in the wellbore has been relieved so as to replace gases in the wellbore; and lowering an oil pipe in the wellbore to the location of the bridge plug. The method for lowering an oil pipe in a gas well without well-killing, the soluble bridge plug and the material preparation method thereof provided in the present invention successfully solve the problem of high cost for lowering an oil pipe under pressure after a fracturing fluid has been injected into the casing.
Type:
Grant
Filed:
April 4, 2018
Date of Patent:
April 26, 2022
Inventors:
Xianwen Li, Qiaorong Han, Yanming Zhang, Xu Ma, Zhanguo Ma, Yangming Hu, Changjing Zhou, Yuanxiang Xiao, Huaqiang Shi, Baochun Chen, Yonghong Gu, Xiaoyong Wen, Xuan'ang Lai, Yong Ding, Liang Ye, Qianyun Zhao, Xinxing Ma, Yajuan Wang, Man Bi, Hua Shi, Mingfang He, Xiaorui Liu, Wei Gao, Hongying Li, Yun Ling, Ruifen Hao, Lei Shen, Guohui Su, Shaowei Zhou, Shusheng Li, Zhe Li