氟化

It is prepared from pentachluorobenzonitrile by using KF as fluoride to substitute chlorine in the presence of benzonitrile under high temperature. But owing to the low solubility of KF and rigor synthesis condition, and the parallel auxiliary reactions, the speed of reaction as well as the yield is very low.

五氟苯甲腈的合成开发以五氯苯甲腈为原料在较高的温度下用氟化钾做氟化剂，通过取代苯环上氯原子而得到的，由于氟化钾在溶剂中溶解度低，合成条件要求苛刻，反应速度较慢，同时存在有平行竞争副反应，因而反应收率较低，国内尚无厂家生产。

Said mineralizing agent is the fluoric alkali-earth metal salts or alkali metal salts (potassium fluoride or calcium fluoride).

其特征是在磷酸钙盐与碳酸钙盐以2∶1比混合物中，加入0.5～3wt％的含氟离子碱土金属或碱金属盐矿化剂，例如氟化钾、氟化钙等。

Teflubenzuron was synthesized from 2,4-difluoronitrobenzene and 2,6-dichlobenil as starting reagent through six-step reaction with the yield of 75.3%.3,5-Dichloro-2,4-difluoroaniline was synthesized by chlorination,reduction reaction from 2,4-difluoronitrobenzene,the yield was 84.5%;2,6-difluorobenzamide with the yield of 87.7% was synthesized by fluoridation and hydrolysis from 2,6-dichlobenil.

以2，4-二氟硝基苯和2，6-二氯苯腈为起始原料，经过6步反应合成伏虫隆，总收率为75.3%。以2，4-二氟硝基苯为原料，经过氯化、还原反应合成3，5-二氯-2，4-二氟苯胺，产率为84.5%；以2，6-二氯苯腈为原料，经过氟化和水解，制得2，6-二氟苯甲酰胺，产率为87.7%；将Ⅱ与二碳酸酯酰化，合成2，6-二氟苯甲酰异氰酸酯，产率为91.3%；Ⅲ与Ⅰ加成，得到杀虫剂伏虫隆，产率为95%。

Reaction conditions are studied, and the result shows that it is better to adopt mercuric oxide or mercuric fluoride as fluorination catalyst with reaction temperature -20~-10℃.

结果表明，采用氧化汞或氟化汞作氟化催化剂、氟化氢作溶剂较好，适宜的反应温度为－20~-10℃，较长的反应时间(48 h)和增加氟化氢和催化剂的量有利于氟化。2-氯－5-三氯甲基吡啶的转化率和选择率均可达到97%以上。

An abnormal condition caused by excessive intake of fluorine ,as from fluoridated drinking water,characterized chiefly by mottling of the teeth.

氟中毒由于过量摄入氟而导致牙齿产生色斑的不正常状况，如饮用氟化的水全氟胍可以由于的三聚氰酰胺，用5%的氟在约－16℃直接进行氟化制得。

Fluoride with sodium fluoride, potassium fluoride, stannous fluoride and sodium monofluorophosphate.

氟化物有氟化钠，氟化钾，氟化亚锡及单氟磷酸钠。

Compared to prior art, the method effectively resolves disadvantage that polymer, which is generated by tetracarbon octafluoride, on side wall of the welding pad is more and not easy to be cleaned, reduces polymer generation on side wall of the welding pad by reducing concentration of the tetracarbon octafluoride and correspondingly adding carbon tetrafluoride.

与现有技术相比，本发明有效解决了由于八氟化四碳产生的聚合物较多而造成焊垫侧壁的聚合物不易被清洗的缺点，在不影响刻蚀效果的前提下适量降低八氟化四碳的浓度，而对应加入四氟化碳，有效减少在焊垫侧壁生成的聚合物，该聚合物更容易在后续清洗制程中清洗干净。

The company produces boron trifluoride acetonitrile and family of products based on technology Zhejiang Huangyan chemical synthesis, the plant is the first production of boron trifluoride etherate, one of the manufacturers, with thirty years of history, there is a group engaged in research boron trifluoride and a group of experts with practical experience of staff.

本公司生产三氟化硼乙腈及系列产品的技术主要依托浙江黄岩合成化工厂，该厂是全国最早生产三氟化硼乙醚的厂家之一，具有三十多年的历史，有一批从事研究三氟化硼的专家和一批具有实际操作经验的工作人员。

Methyl-2,3,5,6-tetrafluoro-benzene methanol was synthesized by chlorination, acylation, fluorination, esterifica- tion, reduction, bromization, reduction from terephthalic acid. Tefluthrin was obtained from-(1RS,3RS)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cycolpropa-necarboxylate acid by reacting with 4-methyl-2,3,5,6-tetrafluoro-benzene methanol.

以对苯二甲酸为原料，经氯化、酰氯化、氟化、酯化、还原、溴化、还原七步反应合成了4-甲基-2，3，5，6-四氟苄醇，甲基苄醇与-(1RS，3RS)-3-(2-氯-3，3，3-三氟丙-1-丙烯基)-2，2-二甲基环丙甲酸一步酯化合成了七氟菊酯。

Methods A set of demineralized bovine teeth specimens we re measured for microhardness to assess the degree of remineralization,and other two sets of bovine teeth specimens were examined with polarizing microscope to assess the anti-demineralization and anti-caries effect.

利用显微硬度计测定氟化牛奶和氟水对早期人工龋的再矿化作用。利用偏光显微镜观察氟化牛奶和氟水的抗酸脱矿作用及抗龋作用。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐