alder

英 ['??ld?] 美['?ld?]

TOEFL

復數(shù):?alders;

alder 榿木

來自PIE *el, 樹名。

alder: alder: [OE] Alder is an ancient tree-name, represented in several other Indo-European languages, including German erle, Dutch els, Polish olcha, Russian ol’khá, and Latin alnus (which is the genus name of the alder in scientific classification). Alder is clearly the odd man out amongst all these forms in having a d, but it was not always so; the Old English word was alor, and the intrusive d does not begin to appear until the 14th century (it acts as a sort of connecting or glide consonant between the l and the following vowel, in much the same way as Old English thunor adopted a d to become thunder). The place-name Aldershot is based on the tree alder.
alder (n.): tree related to the birch, Old English alor "alder" (with intrusive -d- added 14c.; the historical form aller survived until 18c. in literary English and persists in dialects, such as Lancashire owler, which is partly from Norse), from Proto-Germanic *aliso (cognates: Old Norse ?lr, Danish elle, Swedish al, Dutch els, German erle), from *el-, the ancient PIE name of the tree (cognates: Russian olicha, Polish olcha, Latin alnus, Lithuanian alksnis).

1. Modification for synthetic purposes on the Diels - Alder adducts 56 and 62 has only rarely been considered.: 為了達到合成的目的,對Diels-Alder加成物(56)和(62)加以改造的問題很少有人考慮.

2. Diels — Alder reaction is one of the important research content in the fields of organic chemistry.: Diels—Alder反應是目前有機化學領域重要研究內容之一.

3. Activated olefinic bond Amine, thiol radical initiator, cationic initiator, dienes ( Diels - alder reactive ).: 活性烯鍵胺, 巰基,引發(fā)劑, 陽離子引發(fā)劑, 烯烴 ( 的Diels-Alder反應 ).

4. They were principally used to catalyze aldol, allylation, Diels - Alder, ene and Friedel - Crafts reactions.: 它們主要被用來催化Aldol, 烯丙基化, Diels-Alder, Ene和 Friedel -Crafts等反應.

5. Diels - Alder reaction of 2 - merhylene - 1 - pheny 1 - 1.3 - butanedione catalysed by zinc chloride as lewis acid with 1.3 - cylcopentadiene was reported.: 以氯化鋅為路易斯酸催化劑,探討了2 ─ 亞甲基─1 ─ 苯基 ─ 1.3 ─ 丁二酮與1.3 ─ 環(huán)戊二烯的Diels─Alder反應.