Kinetic Model of the Process of Polycondensation of Concentrated Phenols of Coal Tar with Formaldehyde
نویسندگان
چکیده
Phenolformaldehyde resins were obtained by polycondensation of concentrated phenols with formaldehyde in the presence hydrochloric acid. Concentration is carried out treating phenolic fraction coal tar an aqueous solution sodium hydroxide followed neutralization water-soluble phenolates The kinetic dependences resin yield and softening temperature on duration process at 333, 353, 373 K obtained. order reaction was determined effective activation energy this a graphical method. In interval 333-373 for reactions, equation dependence
منابع مشابه
the effect of using model essays on the develpment of writing proficiency of iranina pre-intermediate efl learners
abstract the present study was conducted to investigate the effect of using model essays on the development of writing proficiency of iranian pre-intermediate efl learners. to fulfill the purpose of the study, 55 pre- intermediate learners of parsa language institute were chosen by means of administering proficiency test. based on the results of the pretest, two matched groups, one as the expe...
the use of appropriate madm model for ranking the vendors of mci equipments using fuzzy approach
abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...
15 صفحه اولinvestigating the feasibility of a proposed model for geometric design of deployable arch structures
deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...
analysis of reading comprehension needs of the students of paramedical studies: the case of the students of health information management (him)
چکیده ندارد.
15 صفحه اولthe evaluation of language related engagment and task related engagment with the purpose of investigating the effect of metatalk and task typology
abstract while task-based instruction is considered as the most effective way to learn a language in the related literature, it is oversimplified on various grounds. different variables may affect how students are engaged with not only the language but also with the task itself. the present study was conducted to investigate language and task related engagement on the basis of the task typolog...
15 صفحه اولذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Chemistry and Chemical Technology
سال: 2023
ISSN: ['1996-4196']
DOI: https://doi.org/10.23939/chcht17.02.339