化学专业英语课文翻译

化学专业英语课文翻译
化学专业英语课文翻译

01 元素和元素周期表

The number of protons in the nucleus of an atom is referred to as the atomic number, or proton number, Z. The number of electrons in an electrically neutral atom is also equal to the atomic number, Z. The total mass of an atom is determined very nearly by the total number of protons and neutrons in its nucleus. This total is called the mass number, A. The number of neutrons in an atom, the neutron number, is given by the quantity A-Z.

原子核内的质子数被称为原子序数,或质子数,Z。一个电中性原子的电子数量也等于原子序数,Z。原子的总质量接近核内质子数和中子数之和。这个总数被称为质量数A。中子在一个原子中的数量,中子数,给出了的数量为A-Z。

The term element refers to, a pure substance with atoms all of a single kind. To the chemist the "kind" of atom is specified by its atomic number, since this is the property that determines its chemical behavior. At present all the atoms from Z = 1 to Z = 107 are known; there are 107 chemical elements. Each chemical element has been given a name and a distinctive symbol. For most elements the symbol is simply the abbreviated form of the English name consisting of one or two letters, for example:

单质是指,一个纯物质由一种原子组成的。化学家认为这种原子由它的原子数决定,因为它的性质决定了其化学行为。目前所有被知道的原子是Z = 1 到Z = 107的的原子,有107种化学元素。每一种化学元素被给以一个名字和一个独特的符号。对于大多数元素符号都仅仅是英文名称缩写为一个或两个字母,例如: oxygen==O nitrogen == N neon==Ne magnesium == Mg

氧=O 氮=N 氖=Ne 镁=Mg

Some elements,which have been known for a long time,have symbols based on their Latin names, for example:

一些元素,很久以前就被知道的,它们的符号根据他们的拉丁名字符号,例如: iron==Fe(ferrum) copper==Cu(cuprum) lead==Pb(plumbum)

铁= =Fe(ferrum) 铜= =Cu(cuprum) 铅= =Pb(plumbum)

A complete listing of the elements may be found in Table 1.

一个完整的元素表可以被发现于表1。

Beginning in the late seventeenth century with the work of Robert Boyle, who proposed the presently accepted concept of an element, numerous investigations produced a considerable knowledge of the properties of elements and their compounds1. In 1869,D.Mendeleev and L. Meyer, working independently, proposed the periodic law. In modern form, the law states that the properties of the elements are periodic functions of their atomic numbers. In other words, when the elements are listed in order of increasing atomic number, elements having closely similar properties will fall at definite intervals along the list. Thus it is possible to arrange the list of elements in tabular form with elements having similar properties placed in vertical columns2. Such an arrangement is called a periodic table。

在十七世纪后期开始,在工作罗伯特·波以耳,提出当前公认的元素概念,大量的研究产生元素性质及其化合物的知识。在1869年,D.Mendeleev和L. Meyer,

独立工作,提出了周期性的律法。在现代形式,法律规定的元素的性质是原子序数的周期函数。换句话说,当元素的按原子序数增加列清单,有相近的特性的元素落在了明确的间隔在清单上有明确间隔。于是,将具有类似性质的元素排成纵列,从而把元素排成表格形式是可能的。这样的安排被称为一个周期表。

Each horizontal row of elements constitutes a period. It should be noted that the lengths of the periods vary. There is a very short period containing only 2 elements, followed by two short periods of 8 elements each, and then two long periods of 18 elements each. The next period includes 32 elements, and the last period is apparently incomplete. With this arrangement, elements in the same vertical column have similar characteristics. These columns constitute the chemical families or groups. The groups headed by the members of the two 8-element periods are designated as main group elements, and the members of the other groups are called transition or inner transition elements.

每个水平排的横列元素构成一个周期。但应该注意的是周期不同长度的。非常短的周期只包含两种元素,后面跟着两个短周期每个含8元素,然后两个长周期每个由18个元素组成。下一个周期包含32元素,最后一个周期明显不完整的。这样的安排,元素在同一纵列有相似的特性。这些纵列构成化学家庭或组。为首的两个8元素周期的成员被选定作为主族元素,其他组的成员被称为过渡或内在过渡元素。

In the periodic table, a heavy stepped line divides the elements into metals and nonmetals. Elements to the left of this line (with the exception of hydrogen) are metals, while those to the right are nonmetals. This division is for convenience only; elements bordering the line—the metalloids-have properties characteristic of - both metals and nonmetals. It may be seen that most of the elements, including all the transition and inner transition elements, are metals.

在元素周期表中,沉重的阶梯的线把元素分为金属和非金属元素。那条线的左边(除氢)是金属,而那些右边是非金属矿物等。这条线划分只是为了方便。那些与分隔线相临近的元素——准金属,既有金属的性质,又有非金属的性质。可以看出,大部分的元素,是金属元素。

Except for hydrogen, a gas, the elements of group IA make up the alkali metal family. They are very reactive metals, and they are never found in the elemental state in nature. However, their compounds are widespread. All the members of the alkali metal family, form ions having a charge of 1+ only. In contrast, the elements of group IB —copper, silver, and gold—are comparatively inert. They are similar to the alkali metals in that they exist as 1+ ions in many of their compounds. However, as is characteristic of most transition elements, they form ions having other charges as well.

除了氢元素——一种气体元素外,ⅠA族的元素组成了碱金属。它们是非常活泼的金属,它们从未在自然界中以单质状态被发现。然而,它们的化合物是广泛分布的。碱金属的所有成员具有正一价的离子。与此相反,ⅠB族的元素铜、银、和金相对来说是惰性的。它们和碱金属的相似的,因为它们在化合物中以1+离子存在。但是和大多数过渡元素具有的特性一样,它们也能形成其它价的离子。

The elements of group IIA are known as the alkaline earth metals. Their

characteristic ionic charge is 2+. These metals, particularly the last two members of the group, are almost as reactive as the alkali metals. The group IIB elements—zinc, cadmium, and mercury are less reactive than are those of group II A5, but are more reactive than the neighboring elements of group IB. The characteristic charge on their ions is also 2+.

ⅡA族的元素就是通常所说的碱土金属。它们离子的特征价是2+。这些金属,尤其是族中最后两个元素,几乎和碱金属一样活泼。ⅡB 族元素,锌、镉、和汞比那些ⅡA的元素活性低,但比临近的ⅠB族元素活泼。它们的特征价态也是2+。

With the exception of boron, group IIIA elements are also fairly reactive metals. Aluminum appears to be inert toward reaction with air, but this behavior stems from the fact that the metal forms a thin, invisible film of aluminum oxide on the surface, which protects the bulk of the metal from further oxidation. The metals of group IIIA form ions of 3+ charge. Group IIIB consists of the metals scandium, yttrium, lanthanum, and actinium.

除了硼以外,IIIA元素相当活性金属。铝与空气反应后是惰性的,但这一表现源于这一事实:在金属表面形成了一个薄的,不可见的铝的氧化膜,该膜保护大部分金属不会被进一步氧化。ⅢA族金属形成3+的离子。ⅢB族金属由金属钪、钇、镧和锕组成。

Group IV A consists of a nonmetal, carbon, two metalloids, silicon and germanium, and two metals, tin and lead. Each of these elements forms some compounds with formulas which indicate that four other atoms are present per group IV A atom, as, for example, carbon tetrachloride, GCl4. The group IVB metals —titanium, zirconium, and hafnium —also forms compounds in which each group IVB atom is combined with four other atoms; these compounds are nonelectrolytes when pure.

第Ⅳ族有一个非金属,碳,两个准金属硅和锗,还有两个金属,锡和铅组成。这些元素中每一个都形成一些化合物,这些化合物的分子式表明四个其他的原子出现在ⅣA族的原子周围,例如四氯化碳,CCl4。ⅣB族金属——钛、锆和铪,也形成每个ⅣB族原子与四个其他族原子结合的化合物,这些化合物纯的时候是非电解质。

The elements of group V A include three nonmetals — nitrogen, phosphorus, and arsenic—and two metals —antimony and bismuth. Although compounds with the formulas N2O5, PCl5, and AsCl5 exist, none of them is ionic. These elements do form compounds-nitrides, phosphides, and arsenides —in which ions having charges of minus three occur. The elements of group VB are all metals. These elements form such avariety of different compounds that their characteristics are not easily generalized.

ⅤA族元素包含三个非金属——氮、磷、和砷,两种金属——锑、铋。尽管它们存在分子式为N2O5,PCl5,AsCl5的化合物,但它们都不是离子型化合物。这些元素形成的化合物——氮化物,磷化物,砷化物,其中离子的价态都是负3价。ⅤB族元素都是金属,这些元素形成多种不同的化合物,它们的特点是不容易推广的。

With the exception of polonium, the elements of group VIA are typical

nonmetals. They are sometimes known, as the, chalcogens, from the Greek word meaning "ash formers". In their binary compounds with metals they exist as ions having a charge of 2-. The elements of group ⅦA are all nonmetals and are known as the halogens. from the Greek term meaning "salt formers. ” They are the most reactive nonmetals and are capable of reacting with practically all the metals and with most nonmetals, including each other.

除了钋的元素以外,ⅥA族元素都是典型的非金属。它们有时候被称为硫族,来自希腊字,意思是“灰源体”。它们与金属形成的二元化合物中以2-价的离子存在。ⅦA的元素都是非金属,被称为卤素。来自希腊语,意即“盐源体”。它们是最活泼的非金属,并能够与几乎所有的金属和非金属包括它们自己反应。

The elements of groups ⅥB, ⅦB, and VIIIB are all metals. They form such a wide Variety of compounds that it is not practical at this point to present any examples as being typical of the behavior of the respective groups.

ⅥB,ⅦB,VIIIB元素都是金属。它们形成各种不同的化合物,在这一点上我们甚至不能举出任何能表现各族元素典型变化的例子。

The periodicity of chemical behavior is illustrated by the fact that. excluding the first period,each period begins with a very reactive metal. Successive element along the period show decreasing metallic character, eventually becoming nonmetals, and finally, in group ⅦA, a very reactive nonmetal is found. Each period ends with a member of the noble gas family.

化学行为的周期性可以通过这样的事实阐明。除了第一周期,每一个周期开始于一个非常活泼的金属。周期中的连续元素显示,金属性逐渐降低,最终成为非金属。最后,在ⅦA,一个很活泼的非金属元素。每一个周期以一个惰性气体元素结束

02非金属元素

We noted earlier. that -nonmetals exhibit properties that are greatly different from those of the metals. As a rule, the nonmetals are poor conductors of electricity (graphitic carbon is an exception) and heat; they are brittle, are often intensely colored, and show an unusually wide range of melting and boiling points. Their molecular structures, usually involving ordinary covalent bonds, vary from the simple diatomic molecules of H2, Cl2, I2, and N2 to the giant molecules of diamond, silicon and boron.

我们早就注意到,非金属呈现出来的性质与金属有极大的不同。一般来说,非金属是电和热的不良导体(石墨碳是里例外);他们是易碎的,有强烈的颜色,并表现出异常广泛的融点和沸点。他们的分子结构,通常是包括了普通的共价键的变化,从简单的双原子分子的H2,,Cl2,I2和N2到大分子的金刚石,硅和硼。

The nonmetals that are gases at room temperature are the low-molecular weight diatomic molecules and the noble gases that exert very small intermolecular forces. As the molecular weight increases, we encounter a liquid (Br2) and a solid (I2) whose vapor pressures also indicate small intermolecular forces. Certain properties of a few nonmetals are listed in Table 2.

低分子量的非金属双原子分子在室温时是气体,且分子间的作用力小。随着分子量的增大,我们遇到了液体(Br2)和固体(i),他们的蒸气压也表明分子间的

作用力小。一些非金属的确定的性质都列在表2。

Simple diatomic molecules are not formed by the heavier members of Groups V and VI at ordinary conditions. This is in direct contrast to the first members of these groups, N2 and O2. The difference arises because of the lower stability of π bonds forme d from p orbitals of the third and higher main energy levels as opposed to the second main energy level2. The larger atomic radii and more dense electron clouds of elements of the third period and higher do not allow good parallel overlap of p orbitals necessary for a strong π bond. This is a general phenomenon —strong π bonds are formed only between elements of the second period. Thus, elemental nitrogen and oxygen form stable molecules with both σ and π bonds, but other members of their groups form more stable structures based on σ bonds only at ordinary conditions. Note3 that Group VII elements form diatomic molecules, but π bonds are not required for saturation of valence.

通常条件下,简单的双原子分子并不是由第五族和第六族相对更重的成员形成。这直接与这两组的第一个成员,氮气和氧气形成对比。差别的出现时由于与第二主能级相反,第三和更高主能级的p轨道形成的π键稳定性低。原子半径更大和电子云密度更密集的第三和更高周期元素不允许轨道上良好的平行重叠对于强π键是必须的。这是一个普遍的现象——强π键只有在第二周期元素间形成。因此,元素氮、氧由σ 和π键形成稳定的分子,但它们组族的其他成员,形成稳定结构σ键只有在普通的条件才行。注意第七组族元素形成双原子分子,但π键饱和度不做要求。

Sulfur exhibits allotropic forms. Solid sulfur exists in two crystalline forms and in an amorphous form. Rhombic sulfur is obtained by crystallization from a suitable solution, such as CS2, and it melts at 112°C. Monoclinic sulfur is formed by cooling melted sulfur and it melts at 119°C. Both forms of crystalline sulfur melt into S-gamma, which is composed of S8 molecules. The S8 molecules are puckered rings and survive heating to about 160°C. Above 160°C, the S8 rings break open, and some of these fragments combine with each other to form a highly viscous mixture of irregularly shaped coils. At a range of higher temperatures the liquid sulfur becomes so viscous that it will not pour from its container. The color also changes from straw yellow at sulfur's melting point to a deep reddish-brown as it becomes more viscous.

Allotropic

硫表有同素异形体。固体硫以两结晶形式和一种无定形的形式存在。斜方硫是通过适当的溶液结晶得到的,如CS2,在112°C的融化。单斜硫是由冷却熔化的硫形成,它的熔点是119°C。两种结晶硫都熔化成S-gamma,由S8分子组成。S8的分子呈褶皱环状耐高温达160°C。超过160°C,S8环断开,其中的一些片段相互结合形成一个高粘度的、形状不规则的混合物。在较高的温度范围内,液态硫变得非常粘稠以至于不能从容器中倒出。颜色也从熔点是的稻草黄色变为深红褐色,因为它变得更加粘稠。

As4 the boiling point of 444 °C is approached, the large-coiled molecules of sulfur are partially degraded and the liquid sulfur decreases in viscosity. If the hot liquid sulfur is quenched by pouring it into cold water, the amorphous form

of sulfur is produced. The structure of amorphous sulfur consists of large-coiled helices with eight sulfur atoms to each turn of the helix; the overall nature of amorphous sulfur is described as3 rubbery because it stretches much like ordinary rubber. In a few hours the amorphous sulfur reverts to small rhombic crystals and its rubbery property disappears.

接近沸点444°C时,大盘绕分子形状的硫逐渐降解,并且液体硫粘度降低。如果把热的液体硫倒冷水里骤冷,就会产生无定形硫。无定形硫由八个硫原子组成大螺旋盘绕,自然界中一切无定形硫被描述为橡胶状,是因为它像普通橡胶延伸。在几小时无定形硫又还原成斜方的晶体硫,其橡胶性消失。

Sulfur, an important raw material in industrial chemistry, occurs as the free element, as SO2 in volcanic regions, as H2S in mineral waters, and in a variety of sulfide ores such as iron pyrite FeS2, zinc blende ZnS, galena PbS and such, and in common formations of gypsum CaSO4 ? 2H2O, anhydrite CaS O4, and barytes BaSO4 ? 2H2O.Sulfur, in one form or another, is used in large quantities for making sulfuric acid, fertilizers, insecticides, and paper.

硫,工业化学的重要原料,像自由的元素那样出现,如的火山区SO2,矿泉水中的H2S、和各种各样的硫矿石硫如黄铁矿FeS2如铁、闪锌矿ZnS,方铅矿PbS等,共同形成的石膏CaSO4?2 H2O,硬石膏CaSO4,重晶石BaSO4?2 H2O。硫,在一种或另一种形式,用于大量制造硫酸、肥料、杀虫剂、和纸张。

Sulfur in the form of SO2 obtained in the roasting of sulfide ores is recovered and converted to sulfuric acid, although in previous years much of this SO2 was discarded through exceptionally tall smokestacks. Fortunately, it is now economically favorable to recover these gases, thus greatly reducing this type of atmospheric pollution. A typical roasting reaction involves the change: SO2中的硫在硫化矿石焙烧中恢复和转化为硫酸,尽管在过去几年许多的二氧化硫通过特殊的高烟囱被摒弃。幸运的是,现在经济有利用回收这些气体,从而大幅度地减少这种大气污染。一个典型的焙烧反应涉及改变:

2 ZnS +

3 O2—2 ZnO + 2 SO2

2 ZnS +

3 O2-2氧化锌+ 2二氧化硫

Phosphorus, below 800℃consists of tetratomic molecules, P4. Its molecular structure provides for a covalence of three, as may be expected from the three unpaired p electrons in its atomic structure, and each atom is attached to three others6. Instead of a strictly orthogonal orientation, with the three bonds 90° to each other, the bond angles are only 60°. This supposedly strained structure is stabilized by the mutual interaction of the four atoms (each atom is bonded to the other three), but it is chemically the most active form of phosphorus. This form of phosphorus, the white modification, is spontaneously combustible in air. When heated to 260°C it changes to red phosphorus, whose structure is obscure. Red phosphorus is stable in air but, like all forms of phosphorus, it should be handled carefully because of its tendency to migrate to the bones when ingested, resulting in serious physiological damage.

磷,800℃以下由四原子分子组成P4。其分子结构提供价三个共价键,可以从原子结构中三个未成对p电子的预计,每一个原子与另外三个相连。取代完全的正交方向,与三方彼此90°,键角为60°。据称变形力结构是由四个稳定的原子相

互作用,但是它是最活跃的磷形式。这种形式的磷、白色的变体,在空气中自然。当加热到260°C变为红磷,其结构是不清楚的。红色是在空气中磷稳定,但是,就像所有形式的磷,它应该谨慎处理因摄入体内后会进入到骨头,导致严重的生理伤害。

Elemental carbon exists in one of two crystalline structures — diamond and graphite. The diamond structure, based on tetrahedral bonding of hybridized sp3 orbitals, is encountered among Group IV elements. We may expect that as the bond length increases, the hardness of the diamond-type crystal decreases. Although the tetrahedral structure persists among the elements in this group —carbon, silicon, germanium, and gray tin —the interatomic distances increase from 1.54 A for carbon to 2.80 A for gray tin. Consequently . the bond strengths among the four elements range from very strong to quite weak. In fact, gray tin is so soft that it exists in the form of microcrystals or merely as a powder. Typical of the Group IV diamond-type crystalline elements, it is a nonconductor and shows other nonmetallic properties7.

元素碳以两种晶体结构存在——金刚石和石墨。金刚石结构基于四面体的sp3的杂化轨道结合,是在第四族元素中遇到的。我们可以猜想,随着键长增加,金刚石晶形硬度降低。虽然四面体结构在这些元素中存在这个-碳、硅、锗,和灰锡-原子距离由碳的1.54提高到灰锡的2.80 A。因此。四大元素的键作用力范围有非常强到相当薄弱。事实上,灰锡是柔软的,它以微晶形式存在,或只是一种粉末。第四主族钻石结晶型结晶元素的典型,他是一个绝缘体并显示其它非金属性质。

06无机化合物的分类

The Classes of Compounds

Thousands and tens of thousands of compounds are known to the chemist today. It would be impossible to learn properties and behavior of even a fraction of this number if it had to be done on the basis of individual compounds1. Fortunately, most chemical compounds can be grouped together in a few classes. Then, if we can properly classify a compound . we are at once aware of the general properties of the compound from knowledge of the properties of that class or group of compounds. For example. HCl is classed as an acid. and by becoming familiar with the behavior of acids as a distinct class, we are at once aware of the general properties of the compound2. A great many of the compounds we are to study may be classified as acids, bases, salts, metallic oxides, or nonmetallic oxides. Of these five classes of compounds, the first three — acids, bases, and salts —are by far the most important3…

今天成千上万种化合物已被化学家所知。如果根据个别化合物来了解这么多化合物的性质和行为,即使是其中一小部分也是不可能的。所幸的是,大多数化合物可以被归为几类。这样,如果我们可以真确的对一个化合物进行分类。我们就可以根据这类化合物的性质知道这个化合物的一般性质。例如,HCl是

一种酸,因为已经熟悉酸的性质,我们就可以立即知道这一化合物的一般性质。我们学过的大多数化合物可以分为酸、碱、盐、金属氧化物、非金属氧化物。这五类化合物,前三种——酸、碱、盐——是最重要的。

When an acid, base, or salt is dissolved in water the resulting solution is a conductor of the electric current and is termed an electrolyte. If no conduction of current occurs, the compound is known as a nonelectrolyte.

当一个酸、碱、盐溶于水中的溶液是一种电流的导体被称为电解质。如果没电流产生则该化合物被称为非电解质。

Classification of Common Compounds

常见的化合物分类

By looking at the chemical formulas we may classify many common compounds in the following way.

通过观察化学公式中我们将许多普通化合物以如下方式分类。

1. Acids, in the conventional sense, may be recognized by noting that the H is written first in the formula and that the rest of the compound is generally nonmetallic. Ex., HCl, H2SO4, HClO.

1。酸,用常规的感觉,会被注意到的H被写在分子式的前面,化合物剩下的部分一般为非金属。例、盐酸、硫酸、HClO。

2. Conventional bases have OH radicals written last in the formula. The first part of the formula is usually a metal. Ex., NaOH, Ca(OH)2, Fe(OH)3, 2。传统的碱含有氢氧根写在分子式的后面。分子式的前面一般为金属。例、氢氧化钠、钙(OH)2、铁(OH)3,

3. A salt consists of a metal, written first, combined with a non-metal or radical written last in a formula. Ex., NaCl, Fe2(SO4)3, Ca(ClO)2.

3。盐是包含金属,写第一,再加上一个非金属或基团写在分子式的最后。例、氯化钠、导管(SO4)3、钙(ClO)2 .

4. Oxides are compounds containing oxygen and only one other element.

4。氧化合物仅包含氧和其他一种元素。

If the element other than oxygen is a nonmetal, the oxide is classed as a nonmetal oxide or an acidic anhydride. The latter name comes about because water added to nonmetal oxides under certain conditions produces acids. Likewise, if water is removed from an acid containing oxygen, the acid anhydride (without water) results.

如果元素除了氧是一种非金属,氧化物被归类为非金属氧化物或酸酐。后者的名字是由于水加到非金属氧化物在一定条件下产生的酸。同样地,如果水从含氧酸中被移走,结果会产生酸酐。

The other class of oxides, metallic oxides or basic anhydrides, consist of oxygen combined with a metal. When water is added under proper conditions to basic anhydrides, bases result and vice versa. Acids

另一类氧化物,金属氧化物或碱酐,由氧结合一种金属。当水加入碱酐中在合适的条件下,有碱生成,反之亦然。酸

All acids in the conventional sense contain hydrogen, which may be replaced by metals. The negative portion of the acid molecule is composed of a nonmetal

or a radical (negative valence group). These negative valence groups (except oxide and hydroxide)are often referred to as acid radicals. All acids are covalent compounds in which the atoms are held together by a sharing of electrons. When an acid is dissolved in water, ions are formed as a result of the transfer of a hydrogen ion(proton) from the acid molecule to the water molecule---for example,

所有传统意义上的酸含氢,并可能被取代的金属。酸分子负价的部分由一个非金属或一个基团(负价组)组成。这些负价基团(除氧化物和氢氧化物)常被称为酸根。所有酸都是共价化合物,它们的原子通过公用电子连接。当一种酸溶解在水中,酸中的氢离子转移到水分子中。-例如,

This is a case of coordinate valence, in which an unused pair of electrons from the water molecule combines with a hydrogen ion to form a hydronium ion. The hydronium ion is a hydrated hydrogen ion or proton (H+ *H2O) and, while the ionization of acids in aqueous solution depends on its formation, we shall ordinarily use the simple H+ in writing equations. Such equations are thereby simplified and easier to balance.

这是一种配位价,水中未使用的一对电子结合氢离子形成一个水合离子。离子水合离子的一个水合氢离子或质子(H + * H2O),当这种形式的酸在水溶液中电离时,我们通常使用简单H +写方程。这类方程的简化,从而更容易被配平。

The chief characteristic of an acid is its ability to furnish hydrogen ions (protons); therefore. an acid is usually defined as a substance which may furnish protons.

酸的主要性质是提供氢离子(即质子)的能力。因此,我们把能够提供质子的物质定义为酸。

Properties of Acids. In general, aqueous'solulions of acids are characterized by the following properties;

酸的性质。一般来说,酸的水溶液具有下列性质;

1. They have a sour taste. Lemons . oranges . and other citrus fruits owe their sour taste to' the presence of citric acid; the taste of sour milk is due to the presence of lactic acid.

1。他们有一种酸味。柠檬、桔子和其他柠檬水果由于柠檬酸的存在而具有酸味,酸奶的酸味是由于乳酸的存在。

2. They turn blue litmus paper red. Litmus is a dye which has a red color in acid solution and a blue color in basic solution; paper which has been soaked in litmus is referred to as litmus paper. Substances of this type, which enable us to determine whether a given solution is acid or basic, are called indicators. Methyl orange and phenolphthalein are other indicators frequently used by chemists.

2。它能使蓝色石蕊纸变成了红色。石蕊是一种染料,在酸溶液中显红色,在碱性溶液中显蓝色:浸泡在石蕊中的纸被称为石蕊纸。这种类型的物质,它使我们能够确定一个溶液是酸性还是碱性,被称为指标剂。甲基橙和酚酞是经常被化学家使用的其他指示剂。

3. They react with certain metals to produce hydrogen. Reactions of this type were studied in connection with the preparation of hydrogen.

3。它们与金属反应产生氢。这种与制备氢有关的反应进行了研究。

4. They react with bases to produce salts and water.

4。它们与碱反应生产盐和水。

Common strong acids are H2SO4, HNO3, HCl, HBr, and HI. Most other acids are generally only partially ionized and consequently only moderately strong or weak.

常见的强酸有硫酸、硝酸、盐酸、溴酸、碘酸。其他大多数酸通常只有部分离子化,因此只是中强或弱酸。

Bases

All metallic hydroxides are classed as conventional bases. Of the common bases only NaOH, KOH, Ca(OH)2 and Ba(OH)2 are appreciably soluble in water. If these compounds are dissolved in water, the OH~ is common to all of their solutions.

所有的金属氢氧化物都被视为传统的碱。常见的碱只有氢氧化钠,KOH、钙(OH)2和钡(OH)2是可溶于水。如果这些化合物被溶解在水中,都会产生氢氧根。

An aqueous solution of NH3 is also classed as a base, since OH- ions are present in the solution.

NH3水溶液的也被归类为碱,因为因为溶液中有氢氧根产生。

In each of these compounds we find a combination of a metal (or NH4) with the hydroxide group. Just as the characteristic part of an acid is hydroxide ion, so the characteristic part of a base in water solution is the hydroxide ion, OH~. Later the concept of a base will be extended to include substances which do not furnish hydroxide ions in solution.

我们发现每一个这些化合物由一个金属(或NH4)与氢氧根结合。正如酸特色部分是氢离子,所以碱特色的部分在水溶液中是氢氧根。后来碱的概念将延伸到包括在溶液中不提供氢离子的物质。

Properties of Bases. In general, water solutions of metallic hydroxides (bases) exhibit the following properties:

碱的性质。一般来说,金属氢氧化物的水溶液具有以下特点:

1. Bitter taste.

1。苦味。

2. Soapy or slippery feeling.

2。肥皂或滑感。

3. Turn red litmus paper blue.

3。是红色石蕊纸变蓝。

4. React with acids to form salts and water.

4。与酸反应生成盐和水。

5. Most metallic hydroxides are insoluble in water. Of the common ones, only NaOH, KOH, Ca(OH)2, Ba(OH)2, and NH3 are soluble.

5。大多数金属氢氧化物是不溶于水。常用的,只有氢氧化钠,KOH、钙(OH)2,巴

(OH)2,NH3能溶解。

The common strong bases are NaOH, KOH, Ca(OH)2, and Ba(OH)

常见的强碱有氢氧化钠,KOH、钙(OH)2,巴(OH)

2. Salts An acid reacts with a base to produce a salt and water. Hydrogen from the acid combines with hydroxide from the base to form water molecules.

2。盐一种酸和一种碱起反应时产生一种盐和水。酸中的氢结合碱中的氢氧根形成水分子。

The reaction of an acid with a base is called neutralization. If all the water is removed by evaporation from the solution after the reaction, the positive ions from the base and the negative ions from the acid form a crystal lattice of solid salt.

一种酸和一种碱的反应被称为中和反应。如果反应后溶液中所有的水被完全蒸发,碱中的阳离子和酸中的阴离子组成晶格状的固体盐。

It was shown that the compound sodium chloride, a salt, is an electrovalent compound and is ionized in the solid or crystalline state. The crystal is made up of positive sodium ions and negative chloride ions oriented in a definite pattern. In general, most salts in the crystalline state are electrovalent and are composed of ions oriented in a definite way.

结果表明氯化钠,一种盐,是一个电价的化合物在固体或晶体的状态下电离。这种晶体是正的钠离子和负的氯离子以一个定向的模式组成。一般来说,大多数盐在水晶状态是电价的,由离子以一种明确的方法组成。

10 烷烃alkanes

Number of Isomers

10 ALKANES

10 烷烃

Number of Isomers

异构体数目

The compounds now assigned the generic name alkane are also referred to as saturated hydrocarbons and as paraffin hydrocarbons. The word paraffin, from the Latin parum affinis(slight affinity)refers to the inert chemical nature of the substances and is applied also to the wax obtanable from petroleum and consisting of a mixture of higher alkanes.

现在总称为烷烃和化合物也被叫作饱和烃和链烷烃。这个词来源于拉丁语的parum affinis(轻微的亲和力)指的是物质化学惰性,也被用于能从石油中获得由高级烷烃组成的石蜡。

Derivation of the formulas of the pentanes (3 isomers), hexanes (5). and

heptanes(9) has already demonstrated the sharp rise in diversity with increasing carbon content.

已经证明戊烷,己,庚烷等结构式的多样性随碳含量的增加急剧增加。Normal Alkanes

正构烷烃

Successive members of the series differ in composition by the increment CH2 and form a homologous series. Thus heptane and octane are homologous hydrocarbons; icosane is a higher homolog of methane.

这一系列所以烷烃的区别在于它们的组成上含有递增的CH2基团,并构成了一个同系列。因此庚烷和辛烷是同一系列的烃,二十烷是甲烷的更高级同系物。Saturated Unbranched — Chain Compounds and Univalent Radicals

饱和无支链的链状化合物及其一价基团。

The first four saturated unbranched acyclic hydrocarbons are called methane . ethane, propane and butane. Names of the higher members of this series consist of a numerical term, followed by "-ane" with elision of terminal "a" from the numerical term. Examples of these names are shown in the table below. The generic name of- saturated acyclic hydrocarbons (branched or unbranched) is “alkane.”

前四个饱和的无支链的无环状的碳氢化合物被称作:甲烷,乙烷,丙烷和丁烷。这一系列中更高级成员的名称由去掉数字末尾的a 在加上ane的数字术语构成。下列表中是这些名称的例子。饱和非环碳氢化合物的总称为烷烃。

Examples of names: (n = total number of carbon atoms)

实例名称:(n =总人数的碳原子)

Saturated branched acyclic hydrocarbon is named by prefixing the designations of the side chains to the name of the longest chain which is numbered from one end to the other by Arabic numerals, the direction being so chosen as to give the lowest numbers possible to the side chains. When series of locants containing the same number of terms are compared term by term, that series is "lowest" which contains the lowest number on the occasion of the first difference1. This principle is applied irrespective of the nature of the substituents.

饱和有支链的碳氢化合物命名是把支链的名称加到最长链的名称前。最长链是用阿拉伯数字从一端向另一端编号,这样选择编号方向时尽可能是支链位次具有最低的编号。当逐一比较包含着相同碳原子数目的许多位次时,根据第一个位次差异,含最低数字的是最低者。这一原则的应用与取代基的性质无关

The presence of identical unsubstituted radicals is indicated by the appropriate multiplying prefix di-, tri-, tetra-, penta- , hexa- , hepta-, octa- , nona-, deca , etc. 相同的unsubstituted激进分子的存在表明,适当增加迪-前缀、三-,表示“四”,表示“五”,海格萨-,表示“七”,octa -,将纳米-,deca等。

Univalent radicals derived from saturated acyclic hydrocarbons by removal of hydrogen from a terminal carbon atom are named by replacing the ending " —ane" of the name of the hydrocarbon by "—yl". The carbon atom with the free valence is numbered as 1. As a class, these radicals are called normal, or unbranched chain, alkyls.

饱和的非环状碳氢化合物末端碳原子上去掉氢而衍生的一价基团,在命名时是

将碳氢化合物名称末尾的ane换成yl。含有自由价的碳原子被编号为1位,作为一类,这些基团被称作常规的或无支链的烷基。

Stability. — Alkanes are relatively inert, chemically, since they are indifferent to reagents which react readily with alkenes or with alkynes. n-Hexane, for example, is not attacked by concentrated sulfuric acid, boiling nitric acid, molten "sodium hydroxide, potassium permanganate, or chromic acid; with the exception of sodium hydroxide, these reagents all attack alkenes at room temperature. The few reactions of which alkanes are capable require a high temperature or special catalysis.

稳定性。-化学上烷烃是相对惰性的,对于那些很易与烯烃和炔烃反应的试剂,它们显出很高的惰性。如正己烷,不能与浓硫酸,熔融的氢氧化钠,高锰酸钾或铬酸反应。除了氢氧化钠外,这些试剂在常温下都易与烯烃反应。能与烷烃发生少数几个反应几乎都需要较高的温度或特殊催化剂。

Halogenation. —If a test tube containing n-hexane is put in a dark place and treated with a drop of bromine, the original color will remain undiminished in intensity for days. If the solution is exposed to sunlight, the color fades in a few minutes. and breathing across the mouth of the tube produces a cloud of condensate revealing hydrogen bromide as one reaction product. The reaction is a photochemical substitution:

卤化作用。——如果把一个盛有正己烷的试管放在暗处,并用一滴溴处理,几天后原有的颜色仍保留不褪色。假如将溶液暴露在太阳光下,颜色几分钟就会退去,并可以在试管口产生呈现出来的雾状冷凝物溴化氢。这个反应是光化学取代反应。

Chlorination of alkanes is more general and more useful than bromination and can be effected not only photochemically but also by other methods.

氯烷烃的氯代比溴代更普遍更有用,它不仅在光化学条件下实现,而且可以利用其他方法实现。

Light initiates chlorination of an alkane by converting chlorine molecules into chlorine atoms by a process of hemolysis, in which a covalent bond is severed and one electron is retained by each of the atoms forming the bond: Cl:Cl —→Cl ? + C1? . A chlorine atom has an odd, or unpair ed electron and is a free radical. Because of the tendency of atoms to attain their normal valence shells, any free radical is a highly reactive species. Photochemical chlorination proceeds through a succession of free radicals; it is a free radical chain reaction. The chain initiating step (1 ), hemolytic fission of chlorine molecules, produces chlorine free radicals; in chain propagating steps, a chlorine radical attacks a molecule of alkane to produce hydrogen chloride and an alkyl radical (2), which in turn attacks a chlorine molecule to produce a chloroalkane and a chlorine radical (3). Since chlorine-radicals required in step (2) are regenerated in step (3), the two reactions together constitute a chain which, if both reactions proceeded with perfect efficiency, would be self-propagating without further requirement of light energy, The efficiency. however. is not perfect, for chlorine radicals can recombine (4), combine with alkyl radicals ( 5), or dissipate energy by collision with the flask wails. Hence continued radiation is required to maintain an

adequate supply of initiating radicals. The chain initiating step requires input of light energy amounting to + 242.8kJ/mole. Step (2), however, is exothermic, since the energy required to break the C — H bond is less than the bond energy of H — Cl. The second chain propagating step (3) is likewise exothermic, and indeed chlorination of an alkane can proceed explosively.

光引发烷烃的氯代反应是将氯气分子通过均裂过程转变为氯原子,在均裂过程中,一个共价键断裂,形成这个键的每个原子仍保留一个电子。一个氯原子有奇数个或未成对电子,它是一种自由基。由于原子具有达到最外层价电子饱和的趋势。任何自由基都是非常活泼的。光化学氯代反应是通过一系列自由基的传递进行的。它是自由基的链反应。链引发阶段(1),即氯分子的均裂,产生了氯自由基都是非常活泼的;在链传递阶段,一个氯自由基和烷烃分子反应,产生氯化氢和一个烷基自由基(2),这个自由基依次再和氯分子反应产生氯代烷。

应用化学专业英语第二版万有志主编版课后答案和课文翻译

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化学专业英语翻译1

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蓝梅主编 给排水科学与工程专业英语部分课文翻译中文版

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[实用参考]大学英语精读第三版第四册课文及课文翻译.doc

Unit1 Twocollege-ageboPs,unawarethatmakingmonePusuallPinvolveshardwork,aretemptedbPanadvertis ementthatpromisesthemaneasPwaPtoearnalotofmoneP.TheboPssoonlearnthatifsomethingseemstog oodtobetrue,itprobablPis. 一个大学男孩,不清楚赚钱需要付出艰苦的劳动,被一份许诺轻松赚大钱的广告吸引了。男孩们很快就明白,如果事情看起来好得不像真的,那多半确实不是真的。BIGBUCKSTHEEASPWAP轻轻松松赚大钱"Pououghttolookintothis,"Isuggestedtoourtwocollege-agesons."ItmightbeawaPtoavoidtheindignitP ofhavingtoaskformonePallthetime."Ihandedthemsomemagazinesinaplasticbagsomeonebadhungon ourdoorknob.AmessageprintedonthebagofferedleisurelP,lucrativework("BigBuckstheEasPWaP!")o fdeliveringmoresuchbags. “你们该看看这个,”我向我们的两个读大学的儿子建议道。“你们若想避免因为老是向人讨钱而有失尊严的话,这兴许是一种办法。”我将挂在我们门把手上的、装在一个塑料袋里的几本杂志拿给他们。塑料袋上印着一条信息说,需要招聘人投递这样的袋子,这活儿既轻松又赚钱。(“轻轻松松赚大钱!”) "Idon'tmindtheindignitP,"theolderoneanswered.“我不在乎失不失尊严,”大儿子回答说。"Icanlivewithit,"hisbrotheragreed.“我可以忍受,”他的弟弟附和道。"Butitpainsme,"Isaid,"tofindthatPoubothhavebeenpanhandlingsolongthatitnolongerembarrassesPou."“看到你们俩伸手讨钱讨惯了一点也不感到尴尬的样子,真使我痛心,”我说。TheboPssaidthePwouldlookintothemagazine-deliverPthing.Pleased,Ilefttownonabusinesstrip.BPmi dnightIwascomfortablPsettledinahotelroomfarfromhome.Thephonerang.ItwasmPwife.Shewantedt oknowhowmPdaPhadgone.孩子们说他们可以考虑考虑投递杂志的事。我听了很高兴,便离城出差去了。午夜时分,我已远离家门,在一家旅馆的房间里舒舒服服住了下来。电话铃响了,是妻子打来的。她想知道我这一天过得可好。 "Great!"Ienthused."HowwasPourdaP?"Iinquired.“好极了!”我兴高采烈地说。“你过得怎么样?”我问道。 "Super!"Shesnapped."Justsuper!Andit'sonlPgettingstarted.Anothertruckjustpulledupoutfront."“棒极了!”她大声挖苦道。“真棒!而且这还仅仅是个开始。又一辆卡车刚在门前停下。”"Anothertruck?"“又一辆卡车?” "Thethirdonethisevening.ThefirstdeliveredfourthousandMontgomerPWards.Thesecondbroughtfour thousandSears,Roebucks.Idon'tknowwhatthisonehas,butI'msureitwillbefourthousandofsomething.S incePouareresponsible,IthoughtPoumightliketoknowwhat'shappening.“今晚第三辆了。第一辆运来了四千份蒙哥马利-沃德百货公司的广告;第二辆运来四千份西尔斯-罗伯克百货公司的广告。我不知道这一辆装的啥,但我肯定又是四千份什么的。既然这事是你促成的,我想你或许想了解事情的进展。” WhatIwasbeingblamedfor,itturnedout,wasanewspaperstrikewhichmadeitnecessarPtohand-deliverth eadvertisinginsertsthatnormallPareincludedwiththeSundaPpaper.ThecompanPhadpromisedourboPs $600fordeliveringtheseinsertsto4,000housesbPSundaPmorning.我之所以受到指责,事情原来是这样:由于发生了一起报业工人罢工,通常夹在星期日报纸里的广告插页,必须派人直接投送出去。公司答应给我们的孩子六百美金,任务是将这些广告插页在星期天早晨之前投递到四千户人家去。 "Pieceofcake!"ouroldercollegesonhadshouted.“不费吹灰之力!”我们上大学的大儿子嚷道。"SiGhundredbucks!"Hisbrotherhadechoed,"Andwecandothejobintwohours!"“六百块!”他的弟弟应声道,“我们两个钟点就能干完!” "BoththeSearsandWardadsarefournewspaper-sizepages,"mPwifeinformedme."TherearethirtP-twot housandpagesofadvertisingonourporch.Evenaswespeak,twobigguPsarecarrPingarmloadsofpaperup thewalk.Whatdowedoaboutallthis?"“西尔斯和沃德的广告通常都是报纸那么大的四页,”妻子告诉我说,“现在我们门廊上堆着三万二千页广告。就在我们说话的当儿,两个大个子正各抱着一大捆广告走过来。这么多广告,我们可怎么办?”"JusttelltheboPstogetbusP,"Iinstructed."TheP'recollegemen.TheP'lldowhatthePhavetodo."“你让孩子们快干,”我指示说。“他们都是大学生了。他们自己的事得由他们自己去做。”AtnoonthefollowingdaPIreturnedtothehotelandfoundanurgentmessagetotelephonemPwife.Hervoic

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大学英语精读第一册课文翻译

大学英语精读第一册课 文翻译 Pleasure Group Office【T985AB-B866SYT-B182C-BS682T-STT18】

第一单元 课程开始之际,就如何使学习英语的任务更容易提出一些建议似乎正当其实。 学习英语的几种策略 学习英语决非易事。它需要刻苦和长期努力。 虽然不经过持续的刻苦努力便不能期望精通英语,然而还是有各种有用的学习策略可以用来使这一任务变得容易一些。以下便是其中的几种: 1.不要以完全相同的方式对待所有的生词。你可曾因为简直无法记住所学的所有生词而抱怨自己的记忆力太差其实,责任并不在你的记忆力。如果你一下子把太多的生词塞进头脑,必定有一些生词会被挤出来。你需要做的是根据生词日常使用的频率以不同的方式对待它们。积极词汇需要经常练习,有用的词汇必须牢记,而在日常情况下不常出现的词只需见到时认识即可。你会发现把注意力集中于积极有用的词上是扩大词汇量最有效的途径。 2.密切注意地道的表达方式。你可曾纳闷过,为什么我们说“我对英语感兴趣”是“I’m interested in English”,而说“我精于法语”则是“I’m good at French”你可曾问过自己,为什么以英语为母语的人说“获悉消息或密秘”是“learn the news or secret”,而“获悉某人的成功或到来”却是“learn of someone’s success or arrival”这些都是惯用法的例子。在学习英语时,你不仅必须注意词义,还必须注意以英语为母语的人在日常生活中如何使用它。 3.每天听英语。经常听英语不仅会提高你的听力,而且有助你培养说的技能。除了专为课程准备的语言磁带外,你还可以听英语广播,看英语电视和英语电影。第一次听录好音的英语对话或语段,你也许不能听懂很多。先试着听懂大意,然后在反复地听。你会发现每次重复都会听懂更多的东西。

化学化工专业英语(课本内容)

第二章科技英语构词法 词是构成句子的要素,对词意理解的好坏直接关系到翻译的质量。 所谓构词法即词的构成方法,即词在结构上的规律。科技英语构词特点是外来语多(很多来自希腊语和拉丁语);第二个特点是构词方法多,除了非科技英语中常用的三种构词法—转化、派生及合成法外,还普遍采用压缩法、混成法、符号法和字母象形法。 2.1转化法(Conversion) 由一种词类转化成另一种词类,叫转化法。例如: water(n.水)→water(v.浇水) charge(n.电荷) →charge(v.充电) yield(n.产率) →yield(v.生成) dry(a.干的) →dry(v.烘干) slow(a.慢的) →slow(v.减慢) back(ad.在后、向后) →back(v.使后退、倒车) square(n.正方形) →square(a.正方形的) 2.2派生法(Derivation) 通过加前、后缀构成一新词。派生法是化工类科技英语中最常用的构词法。 例如“烷烃”就是用前缀(如拉丁或希腊前缀)表示分子中碳原子数再加上“-ane”作词尾构成的。若将词尾变成“-ane”、“-yne”、“-ol”、“-al”、“-yl”,则分别表示“烯”、“炔”、“醇”、“醛”、“基”、等。依此类推,从而构成千成种化学物质名词。常遇到这样的情况,许多化学化工名词在字典上查不到,全若掌握这种构词法,能过其前、后缀分别代表的意思,合在一起即是该词的意义。下面通过表1举例说明。需要注意的是,表中物质的数目词头除前四个另有名称外,其它均为表上的数目词头。 本书附录为化学化工专业常用词根及前后缀。此外还可参阅《英汉化学化工词汇》(第三版)附录中的“英汉对照有机基名表”、“西文化学名词中常用的数止词头”及“英汉对照有机词尾表”。 据估计,知道一个前缀可帮助人们认识450个英语单词。一名科技工作者至少要知道近50个前缀和30个后缀。这对扩大科技词汇量,增强自由阅读能力,提高翻译质量和加快翻译速度都是大有裨益的。 2.3合成法(Composition) 由两个或更多的词合成一个词,叫合成法。有时需加连字符。 如副词+过去分词well-known 著名的 名词+名词carbon steel 碳钢 rust-resistance 防锈 名词+过去分词computer-oriented 研制计算机的 介词+名词by-product 副产物 动词+副词makeup 化妆品 check-up 检查 形容词+名词atomic weight 原子量 periodic table 周期表 动词+代词+副词pick-me-up 兴奋剂 副词+介词+名词out-of-door 户外 2.4压缩法(Shortening) (1)只取词头字母 这种方法在科技英语中较常用。

机电一体化中英文对照外文翻译文献

中英文对照外文翻译文献 (文档含英文原文和中文翻译) By integration of machinery development The modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation, in mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management system has had the huge change, caused the industrial production to enter into “the integration of machinery” by “the machinery electrification” for the characteristic development phase. First, the integration of machinery outline Integration of machinery is refers in the organization new owner function, the power function, in the information processing functio n and the control function introduces the electronic technology, u nifies the system the mechanism and the computerization design and the software which constitutes always to call.

《化学工程与工艺专业英语》课文翻译

Unit1化学工业的研究和开发 One of the main发达国家化学工业飞速发展的一个重要原因就是它在研究和开发方面的投入commitmen t和投资investmen t。通常是销售收入的5%,而研究密集型分支如制药,投入则加倍。要强调这里我们所提出的百分数不是指利润而是指销售收入,也就是说全部回收的钱,其中包括要付出原材料费,企业管理费,员工工资等等。过去这笔巨大的投资支付得很好,使得许多有用的和有价值的产品被投放市场,包括一些合成高聚物如尼龙和聚脂,药品和杀虫剂。尽管近年来进入市场的新产品大为减少,而且在衰退时期研究部门通常是最先被裁减的部门,在研究和开发方面的投资仍然保持在较高的水平。 化学工业technology industry是高技术工业,它需要利用电子学和工程学的最新成果。计算机被广泛应用,从化工厂的自动控制a utomatic control,到新化合物结构的分子模拟,再到实验室分析仪器的控制。 Individual manufacturing一个制造厂的生产量很不一样,精细化工领域每年只有几吨,而巨型企业如化肥厂和石油化工厂有可能高达500,000吨。后者需要巨大的资金投入,因为一个这样规模的工厂要花费2亿5千万美元,再加上自动控制设备的普遍应用,就不难解释为什么化工厂是资金密集型企业而不是劳动力密集型企业。 The major大部分化学公司是真正的跨国公司multinational,他们在世界上的许多国家进行销售和开发市场,他们在许多国家都有制造厂。这种国际间的合作理念,或全球一体化,是化学工业中发展的趋势。大公司通过在别的国家建造制造厂或者是收购已有的工厂进行扩张。 Unit 2工业研究和开发的类型 The applied通常在生产中完成的实用型的或有目的性的研究和开发可以分为好几类,我们对此加以简述。它们是:(1)产品开发;(2)工艺开发;(3)工艺改进;(4)应用开发;每一类下还有许多分支。我们对每一类举一个典型的例子来加以说明。在化学工业的不同部门内每类的工作重点有很大的不同。 (1)产品开发。product development产品开发不仅包括一种新药的发明和生产,还包括,比如说,给一种汽车发动机提供更长时效的抗氧化添加剂。这种开发的产品已经使(发动机)的服务期限在最近的十年中从3000英里提高到6000、9000现在已提高到12000英里。请注意,大部分的买家所需要的是化工产品能创造出来的效果,亦即某种特殊的用途。,或称聚四氟乙烯()被购买是因为它能使炒菜锅、盆表面不粘,易于清洗。(2)工艺开发process development。工艺开发不仅包括为一种全新的产品设计一套制造工艺,还包括为现有的产品设计新的工艺或方案。而要进行后者时可能源于下面的一个或几个原因:新技术的利用、原材料的获得或价格发生了变化。氯乙烯单聚物的制造就是这样的一个例子。它的制造方法随着经济、技术和原材料的变化改变了好几次。另一个刺激因素是需求的显著增加。因而销售量对生产流程的经济效益有很大影响。早期的制造就为此提供了一个很好的例子。 The ability of能预防战争中因伤口感染引发的败血症,因而在第二次世界大战(1939-1945)中,pencillin的需求量非常大,需要大量生产。而在那时,只能用在瓶装牛奶表面发酵的方法小量的生产。英国和美国投入了巨大的人力物力联合进行研制和开发,对生产流程做出了两个重大的改进。首先用一个不同的菌株—黄霉菌代替普通的青霉,它的产量要比后者高得多。第二个重大的流程开发是引进了深层发酵过程。只要在培养液中持续通入大量纯化空气,发酵就能在所有部位进行。这使生产能力大大地增加,达到现代容量超过5000升的不锈钢发酵器。而在第一次世界大战中,死于伤口感染的士兵比直接死于战场上的人还要多。注意到这一点不能不让我们心存感激。 Process development for a new product对一个新产品进行开发要考虑产品生产的规模、产生的副产品以及分离/回收,产品所要求的纯度。在开发阶段利用中试车间(最大容量可达100升)获得的数据设计实际的制造厂是非常宝贵的,例如石油化工或氨的生产。要先建立一个中试车间,运转并测试流程以获得更多的数据。他们需要测试产品的性质,如杀虫剂,或进行消费评估,如一种新的聚合物。 Note that by-products注意,副产品对于化学过程的经济效益也有很大的影响。酚的生产就是一个有代表性的例子。早期的方法,苯磺酸方法,由于它的副产品亚硫酸钠需求枯竭而变的过时。亚硫酸钠需回收和废置成为生产过程附加的费用,增加了生产酚的成本。相反,异丙基苯方法,在经济效益方面优于所有其他方法就在于市场对于它的副产品丙酮的迫切需求。丙酮的销售所得降低了酚的生产成本。 A major part对一个新产品进行工艺开发的一个重要部分是通过设计把废品减到最低,或尽可能地防止可能的污染,这样做带来的经济利益和对环境的益处是显而易见的。 Finally it should be noted that最后要注意,工业开发需要包括化学家、化学工程师、电子和机械工程师这样一支庞大队伍的协同合作才能取得成功。 (3)process improvement工艺改进。工艺改进与正在进行的工艺有关。它可能出现了某个问题使生产停止。在这种情形下,就面临着很大的压力要尽快地解决问题以便生产重新开始,因为故障期耗费资财。 然而,更为常见的commonly,工艺改进是为了提高生产过程的利润。这可以通过很多途径实现。例如通过优化流程提高产量,引进新的催化剂提高效能,或降低生产过程所需要的能量。可说明后者的一个例子是在生产氨的过程中涡轮压缩机的引进。这使生产氨的成本(主要是电)从每吨6.66美元下降到0.56美元。通过工艺的改善提高产品质量也会为产品打开新的市场。 然而,近年来in rencent years,最重要的工艺改进行为主要是减少生产过程对环境的影响,亦即防止生产过程所引起的污染。很明显,有两个相关连的因素推动这样做。第一,公众对化学产品的安全性及其对环境所产生影响的关注以及由此而制订出来的法律;第二,生产者必须花钱对废物进行处理以便它能安全地清除,比如说,排放到河水中。显然这是生产过程的又一笔费用,它将增加所生产化学产品的成本。通过减少废物数量提高效益其潜能是不言而喻的。 然而,请注意note,with a plant对于一个已经建好并正在运行的工厂来说,只能做一些有限的改变来达到上述目的。因此,上面所提到的减少废品的重要性应在新公厂的设计阶段加以考虑。近年来另一个当务之急是保护能源及降低能源消耗。 (4)application development应用开发。显然发掘一个产品新的用处或新的用途能拓宽它的获利渠道。这不仅能创造更多的收入,而且由于产量的增加使单元生产成本降低,从而使利润提高。举例来说,早期是用来制造唱片和塑料雨衣的,后来的用途扩展到塑料薄膜,特别是工程上所使用的管子和排水槽。 我们已经强调emphasis了化学产品是由于它们的效果,或特殊的用途、用处而得以售出这个事实。这就意味着化工产品公司的技术销售代表与顾客之间应有密切的联系。对顾客的技术支持水平往往是赢得销售的一个重要的因素。进行研究和开发的化学家们为这些应用开发提供了帮助。33的制造就是一个例子。它最开始是用来做含氟氯烃的替代物作冷冻剂的。然而近来发现它还可以用作从植物中萃取出来的天然物质的溶解剂。当它作为制冷剂被制造时,固然没有预计到这一点,但它显然也是应用开发的一个例子 。 Unit3设计 Based on the experience and data根据在实验室和中试车间获得的经验和数据,一组工程师集中起来设计工业化的车间。化学工程师的职责就是详细说明所有过程中的流速和条件,设备类型和尺寸,制造材料,流程构造,控制系统,环境保护系统以及其它相关技术参数。这是一个责任重大的工作。 The design stage设计阶段是大把金钱花进去的时候。一个常规的化工流程可能需要五千万到一亿美元的资金投入,有许多的事情要做。化学工程师是做出很多决定的人之一。当你身处其位时,你会对自己曾经努力学习而能运用自己的方法和智慧处理这些问题感到欣慰。 设计阶段design stage的产物是很多图纸: (1)工艺流程图flow sheets。是显示所有设备的图纸。要标出所有的流线和规定的条件(流速、温度、压力、构造、粘度、密度等)。 (2)管道及设备图piping and instrumentation。标明drawings所有设备(包括尺寸、喷嘴位置和材料)、所有管道(包括大小、控制阀、控制器)以及所有安全系统(包括安全阀、安全膜位置和大小、火舌管、安全操作规则)。 (3)仪器设备说明书equipmen specification sheet s。详细说明所有设备准确的空间尺度、操作参数、构造材料、耐腐蚀性、操作温度和压力、最大和最小流速以及诸如此类等等。这些规格说明书应交给中标的设备制造厂以进行设备生产。 3.建造construction After the equipment manufactures当设备制造把设备的所有部分都做好了以后,这些东西要运到工厂所在地(有时这是后勤部门颇具挑战性的任务,尤其对象运输分馏塔这样大型的船只来说)。建造阶段要把所有的部件装配成完整的工厂,首先要做的就是在地面打洞并倾入混凝土,为大型设备及建筑物打下基础(比如控制室、流程分析实验室、维修车间)。 完成了第一步initial activities,就开始安装设备的主要部分以及钢铁上层建筑。要装配热交换器、泵、压缩机、管道、测量元件、自动控制阀。控制系统的线路和管道连接在控制室和操作间之间。电线、开关、变换器需装备在马达上以驱动泵和压缩机。生产设备安装完毕后,化学工程师的职责就是检查它们是否连接完好,每部分是否正常工作。

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