This pattern was set in 1879 when a chemist called Constantin Fahlberg was working with coal tar derivatives at Johns Hopkins University in the hope of discovering a new food preservative.

这一规律最早可追溯到 1879 年，当时一位名叫康斯坦丁·法尔贝格化家在约翰·霍普金斯大研究煤焦衍生物，希望发现一种新食品防腐剂。

The word " spice" cleverly hid the industrial origins of saccharin and the fact that it was made from coal tar: a sticky dark liquid that is a byproduct of burning coal.

“香料” 这个词巧妙地隐藏了糖精工业起源和它是由煤焦事实：煤焦是一种粘稠黑色液体，是燃煤副产品。

Precursor is probably acrylic nitrill or pan which is produced by the petrochemicals industry Pitch obtained from car is sometimes used instead.

前驱体可能是丙烯腈或聚丙烯腈，这些是由石化工业生产。有时会使用从煤焦中获得沥青作为替代品。

In 1907 a chemist combined phenol— a waste product of coal tar— and formaldehyde, creating a hardy new polymer called bakelite.

1907 年， 一位化家将苯酚（一种煤焦废品）和甲醛结合在一起，创造出一种名为电木坚固新型聚合物。

But coal tar is toxic and hard to get rid of without harm the environment.

但煤焦有毒，若不破坏环境则难以清除。

He was attempting to manufacture quinine from aniline, an inexpensive and readily available coal tar waste product.

他试图用苯胺造奎宁，苯胺是一种廉价且容易获得煤焦废料。

I xk y nine from coal tar, coal tarts a thick, brown sticky substance that's produced as a byproduct when coal gas is extracted from coal.

我从煤焦中提取了九种物质，煤焦是一种在从煤中提取煤气时作为副产品产生浓稠、棕色粘性物质。

Some of its chemical components are the same as you find in coal tar.

其中一些化分与煤焦中相同。

There was lots of it around because coal gas was the primary source of light, heat and cooking fuel in most households.

当时它（煤焦）很常见，因为煤气是大多数家庭照明、取暖和烹饪主要能源。

You don't hear a lot about coal tar today, but back then you sure did.

如今，人们很少提及煤焦，但在那时，它确是热门话题。